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diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/10-Design_of_FIR_filters.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/10-Design_of_FIR_filters.ipynb
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+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 10: Design of FIR filters"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.10: Maximally_Flat_FIR_filter_Desig.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Maximally flat FIR filter design\n",
+"Fp=0.2;\n",
+"Fs=0.4;\n",
+"Fc=0.3;\n",
+"Ft=0.2;\n",
+"N0=1+0.5/Ft^2;\n",
+"N0=ceil(N0);\n",
+"alpha=(cos(%pi*Fc))^2;\n",
+"k=5;Mmin=14;\n",
+"L=Mmin-k;\n",
+"N=2*Mmin-1;\n",
+"disp(N,'Hence with this length we can get maximally flat FIR filter with no ripples in passband');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.2: Truncation_and_Windowing.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Truncation and Windowing\n",
+"//(a)N=9,Barlett Window.\n",
+"z=%z;\n",
+"Fc=0.25;\n",
+"n=-4:4;\n",
+"hn=2*Fc*(sinc(0.5*n'*%pi))\n",
+"Wn=1-(2*abs(n'))/8//Barlett window\n",
+"hwn=hn.*Wn\n",
+"Hcz=0;\n",
+"for i=1:length(hwn)\n",
+"     Hcz=Hcz+hwn(i)*(z^((2-i)));\n",
+"end\n",
+"Hcz//indicates delay of 0.15ms\n",
+"//(b)N=6,vonhann Window\n",
+"n1=-2.5:2.5;\n",
+"hn1=2*Fc*(sinc(0.5*n1'*%pi))\n",
+"Wn1=0.5+0.5*(cos(0.4*%pi*n1'))//Vonhann window\n",
+"hwn1=hn1.*Wn1\n",
+"Hcz1=0;\n",
+"for i=1:length(hwn1)\n",
+"     Hcz1=Hcz1+hwn1(i)*(z^((2-i)));\n",
+"end\n",
+"Hcz1//1st sample of hwn is 0 hence delay is 1.5ms"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.3ab: FIR_lowpass_Filter_desig.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//FIR filter design using windows\n",
+"//(a)Design of FIR filter to meet following specifications\n",
+"fp=2;fs=4;Ap=2;As=40;S=20;\n",
+"Fp=fp/S;Fs=fs/S;\n",
+"Fc=0.15;\n",
+"z=%z;\n",
+"N1=3.21/(Fs-Fp);\n",
+"N1=ceil(N1)\n",
+"N2=5.71/(Fs-Fp);\n",
+"N2=ceil(N2)\n",
+"n1=-16:16;\n",
+"n2=-28.5:1:28.5;\n",
+"hn1=2*Fc*(sinc(2*Fc*n1'));\n",
+"hn2=2*Fc*(sinc(2*Fc*n2'));\n",
+"Wn1=0.5+0.5*(cos(2*%pi*n1'/(N1-1)));//Vonhann window\n",
+"Wn2=0.42+0.5*(cos(2*%pi*n2'/(N2-1)))+0.08*(cos(4*%pi*n2'/(N2-1)));//Blackman window\n",
+"hwn1=abs(hn1.*Wn1);\n",
+"hwn2=abs(hn2.*Wn2);\n",
+"[hwn1F,fr1]=frmag(hwn1,256);\n",
+"[hwn2F,fr2]=frmag(hwn2,256);\n",
+"hwn1F1=20*log10(hwn1F);\n",
+"hwn2F1=20*log10(hwn2F);\n",
+"plot2d(fr1,hwn1F1);\n",
+"plot2d(fr2(1:length(fr2)-2),hwn2F1(1:length(fr2)-2));\n",
+"xlabel('Digital frequency');\n",
+"ylabel('Magnitude [dB]');\n",
+"title('Low pass filter using vonhann and Blackmann windows Fc=0.15,vonhann N=33,Blackman N=58');\n",
+"//(b)Minimum length design\n",
+"Fcv=0.1313;\n",
+"Fcb=0.1278;\n",
+"Nv=23;Nb=29;\n",
+"nv=-11:11;\n",
+"nb=-14:14;\n",
+"hnv=2*Fcv*(sinc(2*Fcv*nv'));\n",
+"hnb=2*Fcb*(sinc(2*Fcb*nb'));\n",
+"Wnv=0.5+0.5*(cos(2*%pi*nv'/(Nv-1)));//Vonhann window\n",
+"Wnb=0.42+0.5*(cos(2*%pi*nb'/(Nb-1)))+0.08*(cos(4*%pi*nb'/(Nb-1)));//Blackman window\n",
+"hwnv=abs(hnv.*Wnv);\n",
+"hwnb=abs(hnb.*Wnb);\n",
+"[hwnvF,frv]=frmag(hwnv,256);\n",
+"[hwnbF,frb]=frmag(hwnb,256);\n",
+"hwnvF=20*log10(hwnvF);\n",
+"hwnbF=20*log10(hwnbF);\n",
+"b=gca();\n",
+"xset('window',2);\n",
+"plot(frv,hwnvF);\n",
+"plot(frb,hwnbF);\n",
+"xlabel('Digital frequency');\n",
+"ylabel('Magnitude [dB]');\n",
+"title('Vonhann Fc=0.1313,Minimum N=23,Blackmann Fc=0.1278,Minimum N=29');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.3cd: FIR_filter_Desig.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Design of high pass FIR filter with specifications\n",
+"//fp=4kHZ;fs=2kHZ;Ap=2dB;As=40dB\n",
+"fp=2;fs=4;Ap=2;As=40;S=20;\n",
+"Fp=fp/S;Fs=fs/S;\n",
+"Ft=0.1;\n",
+"Fc=0.15\n",
+"N1=3.47/(Fs-Fp);//hamming\n",
+"N1=int(N1)+1\n",
+"N2=5.71/(Fs-Fp);//blackman\n",
+"N2=int(N2)+1\n",
+"[hn1]=eqfir(N1,[0 0.1;0.2 0.5],[0 1],[1 1]);\n",
+"[HF1,fr1]=frmag(hn1,512);\n",
+"Hf1=20*log10(HF1);\n",
+"[hn2]=eqfir(58,[0 0.1;0.2 0.43],[0 1],[1 1]);\n",
+"[HF2,fr2]=frmag(hn2,512);\n",
+"Hf2=20*log10(HF2);\n",
+"a=gca();\n",
+"plot2d(fr1,Hf1,rect=[0 -120 0.5 4]);\n",
+"plot2d(fr2(1:length(fr2)-5),Hf2(1:length(fr2)-5),rect=[0 -120 0.5 4]);\n",
+"xlabel('Digital Frequency F');\n",
+"ylabel('Magnitude [dB]');\n",
+"xtitle('High pass filter using Hamming and Blackmann windows LPP Fc=0.35');\n",
+"//Minimum Length Design\n",
+"[hn3]=eqfir(22,[0 0.1;0.2 0.43],[0 1],[1 1]);\n",
+"[HF3,fr3]=frmag(hn3,512);\n",
+"Hf3=20*log10(HF3);\n",
+"[hn4]=eqfir(29,[0 0.1;0.2 0.5],[0 1],[1 1]);\n",
+"[HF4,fr4]=frmag(hn4,512);\n",
+"Hf4=20*log10(HF4);\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d(fr3(1:length(fr3)-5),Hf3(1:length(fr3)-5),rect=[0 -120 0.5 4]);\n",
+"plot2d(fr4,Hf4,rect=[0 -120 0.5 4]);\n",
+"xlabel('Digital Frequency F');\n",
+"ylabel('Magnitude [dB]');\n",
+"xtitle('Hamming LPP Fc=0.3293 N=22;Blackmann LPP Fc=0.3277 N=29');\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.4a: Half_Band_lowpass_FIR_filter_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Half band FIR Filter Design\n",
+"//(a)lowpass Half band Filter\n",
+"s=%s;z=%z;\n",
+"fp=8;fs=16;Ap=1;As=50;\n",
+"S=2*(fs+fp);\n",
+"Fp=fp/S;Fs=fs/S;Fc=0.25;\n",
+"delp=(10^(Ap/20)-1)/(10^(Ap/20)+1);\n",
+"dels=10^(-As/20);\n",
+"del=min(delp,dels);\n",
+"As0=-20*log10(del)\n",
+"N1=(As0-7.95)/(14.36*(Fs-Fp))+1;\n",
+"N1=int(N1)+1;\n",
+"B=0.0351*(As0-8.7)\n",
+"[hn1]=eqfir(19,[0 1/6;1/3 0.5],[1 0],[1 1]);\n",
+"[HLPF1,fr1]=frmag(hn1,512);\n",
+"HLPf1=20*log10(HLPF1);\n",
+"a=gca();\n",
+"plot2d(fr1,HLPf1);\n",
+"xlabel('Digital Frequency');\n",
+"ylabel('Magnitude in dB');\n",
+"xtitle('Kaiser half band LPF:B=1.44;Fc=0.25');\n",
+"[hn2]=eqfir(21,[0 1/6;1/3 0.5],[1 0],[1 1]);\n",
+"[HLPF2,fr2]=frmag(hn2,512);\n",
+"HLPf2=20*log10(HLPF2);\n",
+"xset('window',1);\n",
+"plot2d(fr2,HLPf2);\n",
+"xlabel('Digital Frequency');\n",
+"ylabel('Magnitude in dB');\n",
+"xtitle('Hamming half-band LPF:N=21;Fc=0.25');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.4b: Half_Band_bandstop_FIR_filter_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Half band FIR Filter Design\n",
+"//(a)band-stop Half band Filter\n",
+"s=%s;z=%z;\n",
+"fp1=1;fs1=2;fp2=4;fs2=3;Ap=1;As=50;\n",
+"S=2*(fs1+fs2);\n",
+"Fp=0.5*(fs2/S-fs1/S);Fs=0.5*(fp2/S-fp1/S);\n",
+"Fc=0.5*(Fp+Fs);Fo=0.25;\n",
+"delp=(10^(Ap/20)-1)/(10^(Ap/20)+1);\n",
+"dels=10^(-As/20);\n",
+"del=min(delp,dels);\n",
+"As0=-20*log10(del)\n",
+"N1=(As0-7.95)/(14.36*(Fs-Fp))+1;\n",
+"N1=ceil(N1);\n",
+"B=0.0351*(As0-8.7)\n",
+"[hn1]=eqfir(31,[0 0.1;0.2 0.3;0.4 0.5],[1 0 1],[1 1 1]);\n",
+"[HBSF1,fr1]=frmag(hn1,400);\n",
+"HBSf1=20*log10(HBSF1);\n",
+"a=gca();\n",
+"plot2d(fr1,HBSf1);\n",
+"xlabel('Digital Frequency');\n",
+"ylabel('Magnitude in dB');\n",
+"xtitle('Kaiser half band LPF:B=1.44;Fc=0.25');\n",
+"[hn2]=eqfir(35,[0 0.1;0.2 0.3;0.4 0.5],[1 0 1],[1 1 1]);\n",
+"[HF2,fr2]=frmag(hn2,200);\n",
+"HBSf2=20*log10(HF2);\n",
+"xset('window',1);\n",
+"plot2d(fr2,HBSf2);\n",
+"xlabel('Digital Frequency');\n",
+"ylabel('Magnitude in dB');\n",
+"xtitle('Hamming half-band LPF:N=21;Fc=0.25');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.5a: Design_by_Frequency_Sampling.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Fir low pass filter design by frequency sampling\n",
+"z=%z;\n",
+"N=10;\n",
+"magHk=[1 1 1 0 0 0 0 0 1 1];\n",
+"k=[0:7 -1 -2];\n",
+"fik=-%pi*k'*(N-1)/N;\n",
+"for i=1:length(fik)\n",
+"    H1k(i)=magHk(i)*exp(%i*fik(i));\n",
+"end\n",
+"H1n=(dft(H1k,1));\n",
+"H2k=H1k;\n",
+"H2k(3)=0.5*%e^(-%i*1.8*%pi);\n",
+"H2k(9)=0.5*%e^(%i*1.8*%pi);\n",
+"H2n=(dft(H2k,1));\n",
+"H1Z=0;H2Z=0;\n",
+"for i=1:length(H1n)\n",
+"    H1Z=H1Z+H1n(i)*z^(-i); \n",
+"end\n",
+"for i=1:length(H2n)\n",
+"    H2Z=H2Z+H2n(i)*z^(-i); \n",
+"end\n",
+"F=0:0.01:1;\n",
+"F1=0:0.1:0.9;\n",
+"H1F=abs(horner(H1Z,exp(%i*2*%pi*F')));\n",
+"H2F=abs(horner(H2Z,exp(%i*2*%pi*F')));\n",
+"a=gca();\n",
+"plot2d(F1,magHk);\n",
+"plot2d(F,H2F);\n",
+"plot2d(F,H1F);\n",
+"xlabel('Digital Frequency F');\n",
+"ylabel('magnitude');\n",
+"xtitle('Low pass filter using frequency sampling');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.5b: Design_by_Frequency_Sampling.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Fir high pass filter design by frequency sampling\n",
+"z=%z;\n",
+"N=10;\n",
+"magHk=[0 0 0 1 1 1 1 1 0 0];\n",
+"k=[0:5 -4:-1:-1];\n",
+"fik=(-%pi*k'*(N-1)/N)+(0.5*%pi);\n",
+"for i=1:length(fik)\n",
+"    H1k(i)=magHk(i)*exp(%i*fik(i));\n",
+"end\n",
+"H1n=(dft(H1k,1));\n",
+"H2k=H1k;\n",
+"H2k(3)=0.5*%e^(-%i*1.3*%pi);\n",
+"H2k(9)=0.5*%e^(%i*1.3*%pi);\n",
+"H2n=(dft(H2k,1));\n",
+"H1Z=0;H2Z=0;\n",
+"for i=1:length(H1n)\n",
+"    H1Z=H1Z+H1n(i)*z^(-i); \n",
+"end\n",
+"for i=1:length(H2n)\n",
+"    H2Z=H2Z+H2n(i)*z^(-i); \n",
+"end\n",
+"F=0:0.01:1;\n",
+"F1=0:0.1:0.9;\n",
+"H1F=abs(horner(H1Z,exp(%i*2*%pi*F')));\n",
+"H2F=abs(horner(H2Z,exp(%i*2*%pi*F')));\n",
+"a=gca();\n",
+"plot2d(F1,magHk);\n",
+"plot2d(F,H2F);\n",
+"plot2d(F,H1F);\n",
+"xlabel('Digital Frequency F');\n",
+"ylabel('magnitude');\n",
+"xtitle('Low pass filter using frequency sampling');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.6a: Optimal_FIR_Bandstop_Filter_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//optimal Fir band stop filter design\n",
+"fp1=1;fp2=4;fs1=2;fs2=3;\n",
+"Ap=1;As=50;S=10;\n",
+"Fp1=fp1/S;Fp2=fp2/S;Fs1=fs1/S;Fs2=fs2/S;\n",
+"FT=0.1;FC=0.25\n",
+"//calculation of filter length\n",
+"delp=(10^(Ap/20)-1)/(10^(Ap/20)+1);\n",
+"dels=10^(-As/20);\n",
+"N=1+((-10*log10(delp*dels)-13)/(14.6*FT))\n",
+"N1=21;\n",
+"[hn]=eqfir(N1,[0 0.1;0.2 0.3;0.4 0.5],[1 0 1],[1 1 1]);\n",
+"[HF,fr]=frmag(hn,512);\n",
+"Hf=20*log10(HF);\n",
+"a=gca();\n",
+"plot(fr,Hf);\n",
+"xlabel('Digital frequency F');\n",
+"ylabel('Magnitude in dB');\n",
+"xtitle('optimal BSF:N=21;Ap=0.2225;As=56.79dB');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.6b: Optimal_Half_Band_Filter_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//optimal Fir band pass filter design\n",
+"fp=8;fs=16;\n",
+"Ap=1;As=50;S=48;\n",
+"Fp=fp/S;Fs=fs/S;\n",
+"FT=0.1;FC=0.25\n",
+"//calculation of filter length\n",
+"delp=(10^(Ap/20)-1)/(10^(Ap/20)+1);\n",
+"dels=10^(-As/20);\n",
+"del=min(delp,dels);\n",
+"N=1+((-10*log10(del*del)-13)/(14.6*FT));\n",
+"N1=19;\n",
+"[hn]=eqfir(N1,[0 1/6;1/3 0.5],[1 0],[1 1]);\n",
+"[HF,fr]=frmag(hn,200);\n",
+"Hf=20*log10(HF);\n",
+"a=gca();\n",
+"plot(fr,Hf);\n",
+"xlabel('Digital frequency F');\n",
+"ylabel('Magnitude in dB');\n",
+"xtitle('optimal Half band LPF N=17');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.7: Multistage_Interpolation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//The concept of multistage Interpolation\n",
+"//(a)Single stage interpolator\n",
+"Sin=4;Sout=48;\n",
+"fp=1.8;\n",
+"fs=Sin-fp;\n",
+"FT=(fs-fp)/Sout;\n",
+"disp('By using single stage the total filter length is:')  \n",
+"L=4/FT\n",
+"//(b)Two-stage interpolator\n",
+"Sin=[4 12];\n",
+"I=[3 4];//interpolating factors\n",
+"Sout=[12 48];\n",
+"fp=[1.8 1.8];\n",
+"fs=Sin-fp;\n",
+"L1=4*Sout./(fs-fp);\n",
+"L=0;\n",
+"for i=1:length(L1)\n",
+"    L=L+L1(i);\n",
+"end\n",
+"disp('By using 2 stage interpolator filter length is:')\n",
+"ceil(L)\n",
+"//(c)3 stage interpolator with I1=2;I2=3;I3=2\n",
+"Sin=[4 8 24];\n",
+"I=[2 3 2];\n",
+"Sout=[8 24 48];\n",
+"fp=[1.8 1.8 1.8];\n",
+"fs=Sin-fp;\n",
+"L2=4*Sout./(fs-fp);L=0;\n",
+"for i=1:length(L2)\n",
+"    L=L+L2(i);\n",
+"end\n",
+"disp('By using 3 stage interpolator filter length is:')\n",
+"ceil(L)\n",
+"//(d)3 stage interpolator with I1=2;I2=3;I3=2\n",
+"Sin=[4 12 24];\n",
+"I=[3 2 2];\n",
+"Sout=[12 24 48];\n",
+"fp=[1.8 1.8 1.8];\n",
+"fs=Sin-fp;\n",
+"L3=4*Sout./(fs-fp);L=0;\n",
+"for i=1:length(L3)\n",
+"    L=L+L3(i);\n",
+"end\n",
+"disp('By using 2 stage interpolator filter length is:')\n",
+"ceil(L)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.8: Design_of_Interpolating_Filters.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Design of interpolating filters\n",
+"//(a)Design using a single stage interpolator\n",
+"fp=1.8;Sout=48;Sin=4;\n",
+"Ap=0.6;As=50;\n",
+"fs=Sin-fp;\n",
+"//finding ripple parameters\n",
+"delp=(10^(Ap/20)-1)/(10^(Ap/20)+1);\n",
+"dels=10^(-As/20);\n",
+"N=Sout*(-10*log10(delp*dels)-13)/(14.6*(fs-fp))+1;\n",
+"disp('By using single stage interpolator the filter design is:');\n",
+"ceil(N)\n",
+"//Design using 3-stage interpolator with I1=2;I2=3;I3=2\n",
+"Ap=0.2;\n",
+"Sin=[4 8 24];\n",
+"Sout=[8 24 48];\n",
+"fp=[1.8 1.8 1.8];\n",
+"fs=Sin-fp;\n",
+"delp=(10^(Ap/20)-1)/(10^(Ap/20)+1);\n",
+"dels=10^(-As/20);\n",
+"p=14.6*(fs-fp);\n",
+"N1=((-10*log10(delp*dels)-13)./p);\n",
+"N1=(Sout.*N1)+1;N=0;\n",
+"for i=1:length(N1)\n",
+"    N=N+N1(i);\n",
+"end\n",
+"disp('By using single stage interpolator the filter design is:');\n",
+"ceil(N)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 10.9: Multistage_Decimatio.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//The concept of multistage Decimation\n",
+"//(a)Single stage decimator\n",
+"Sin=48;Sout=4;\n",
+"fp=1.8;\n",
+"fs=Sout-fp;\n",
+"FT=(fs-fp)/Sin;\n",
+"disp('By using single stage the total filter length is:')  \n",
+"L=4/FT\n",
+"//(b)Two-stage decimator\n",
+"Sin=[48 12];\n",
+"D=[4 3];//decimating factors\n",
+"Sout=[12 4];\n",
+"fp=[1.8 1.8];\n",
+"fs=Sout-fp;\n",
+"L1=4*Sin./(fs-fp);\n",
+"L=0;\n",
+"for i=1:length(L1)\n",
+"    L=L+L1(i);\n",
+"end\n",
+"disp('By using 2 stage decimator filter length is:')\n",
+"ceil(L)\n",
+"//3 stage decimator with D1=2;D2=3;D3=2\n",
+"Sin=[48 24 8];\n",
+"D=[2 3 2];\n",
+"Sout=[24 8 4];\n",
+"fp=[1.8 1.8 1.8];\n",
+"fs=Sout-fp;\n",
+"L2=4*Sin./(fs-fp);L=0;\n",
+"for i=1:length(L2)\n",
+"    L=L+L2(i);\n",
+"end\n",
+"disp('By using 3 stage decimator filter length is:')\n",
+"ceil(L)\n",
+"//3 stage decimator with I1=2;I2=3;I3=2\n",
+"Sin=[48 24 12];\n",
+"D=[2 2 3];\n",
+"Sout=[24 12 4];\n",
+"fp=[1.8 1.8 1.8];\n",
+"fs=Sout-fp;\n",
+"L3=4*Sin./(fs-fp);L=0;\n",
+"for i=1:length(L3)\n",
+"    L=L+L3(i);\n",
+"end\n",
+"disp('By using 3 stage decimator filter length is:')\n",
+"ceil(L)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/2-Discrete_Signals.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/2-Discrete_Signals.ipynb
new file mode 100644
index 0000000..36b5000
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/2-Discrete_Signals.ipynb
@@ -0,0 +1,486 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 2: Discrete Signals"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.1a: Signal_energy_and_power.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.1.a,pg no.11\n",
+"for i=1:1:50\n",
+"    x(1,i)=3*(0.5)^(i-1);\n",
+"end\n",
+"//summation of x\n",
+"E=0\n",
+"for i=1:1:50\n",
+"    E=E+x(1,i)^2;\n",
+"end\n",
+"disp('the energy of given signal is')\n",
+"E"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.1b: Average_power_of_periodic_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.1b,pg.no.11\n",
+"n=1:1:10;\n",
+"xn=6*cos((2*%pi*n')/4);\n",
+"a=4;\n",
+"p=0;\n",
+"for i=1:1:a\n",
+"    p=p+abs(xn(i)^2);\n",
+"end\n",
+"P=p/a;\n",
+"disp('The average power of given signal is')\n",
+"P"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.1c: Average_power_of_periodic_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.1c,pg.no.11\n",
+"n=1:4;\n",
+"xn=6*%e^((%i*%pi*n')/2);\n",
+"a=4;\n",
+"p=0;\n",
+"for i=1:1:a\n",
+"    p=p+abs(xn(i)^2);\n",
+"end\n",
+"P=p/a;\n",
+"disp('The average power of given signal is')\n",
+"P"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.2: Operations_on_Discrete_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.2,pg no.12\n",
+"x=[0 2 3 4 5 6 7];\n",
+"n1=-3:1:3;\n",
+"y=x;\n",
+"n2=0:1:6;\n",
+"f=x;\n",
+"n3=-5:1:1;\n",
+"g=x(length(x):-1:1);\n",
+"n4=-3:1:3;\n",
+"h=x(length(x):-1:1);\n",
+"n5=-2:1:4;\n",
+"s=x(length(x):-1:1);\n",
+"n6=-5:1:1;\n",
+"a=gca();\n",
+"subplot(231);\n",
+"plot2d3('gnn',n1,x);\n",
+"ylabel('x[n]');\n",
+"subplot(232);\n",
+"plot2d3('gnn',n2,y);\n",
+"ylabel('y[n]=x[n-3]');\n",
+"subplot(233);\n",
+"plot2d3('gnn',n3,f);\n",
+"ylabel('f[n]=x[n+2]');\n",
+"subplot(234);\n",
+"plot2d3('gnn',n4,g);\n",
+"ylabel('g[n]=x[-n]');\n",
+"subplot(235);\n",
+"plot2d3('gnn',n5,h);\n",
+"ylabel('h[n]=x[-n+1]');\n",
+"subplot(236);\n",
+"plot2d3('gnn',n6,s);\n",
+"ylabel('s[n]=x[-n-2]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.3a: Even_and_Odd_parts_of_Discrete_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.3a pg.no.14\n",
+"clear;clc;close;\n",
+"n=-2:2;\n",
+"x1=[4 -2 4 -6 0];\n",
+"x2=0.5*x1//x[n]\n",
+"x3=0.5*[x1(length(x1):-1:1)];//x[-n]\n",
+"xe=(x2+x3);//even part\n",
+"xo=(x2-x3);//odd part\n",
+"a=gca();\n",
+"a.thickness=2;\n",
+"a.x_location='middle';\n",
+"a.y_location='middle';\n",
+"plot2d3('gnn',n,xe,rect=[-4 -6 4 6])\n",
+"xtitle('graphical representation of even part of x[n]','n','x[n]')\n",
+"xset('window',1)\n",
+"b=gca();\n",
+"b.thickness=2;\n",
+"b.y_location='middle';\n",
+"b.x_location='middle';\n",
+"plot2d3('gnn',n,xo,rect=[-2 -4 2 4])\n",
+"xtitle('graphical representation of odd part of x[n]','n','x[n]')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.3b: Even_and_Odd_parts_of_Discrete_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.3a pg.no.14\n",
+"clear;clc;close;\n",
+"x1=[0 0 0 0 0 1 1 1 1 ];\n",
+"n=-4:4;\n",
+"x2=0.5*x1//x[n]\n",
+"x3=0.5*[x1(length(x1):-1:1)]//x[-n]\n",
+"xe=(x2+x3);//even part\n",
+"xo=(x2-x3);//odd part\n",
+"a=gca();\n",
+"a.thickness=2;\n",
+"a.y_location='middle';\n",
+"a.x_location='middle';\n",
+"plot2d3('gnn',n,xe,rect=[-4 -1 4 1]);\n",
+"xtitle('graphical representation of even part of x[n]','n','x[n]')\n",
+"xset('window',1)\n",
+"b=gca();\n",
+"b.thickness=2;\n",
+"b.y_location='middle';\n",
+"b.x_location='middle';\n",
+"plot2d3('gnn',n,xo,rect=[-4 -1 4 1]);\n",
+"xtitle('graphical representation of odd part of x[n]','n','x[n]')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4a: Decimation_and_Interpolation_of_Discrete_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.4a pg.no.17\n",
+"x=[1 2 5 -1];\n",
+"xm=2;//denotes 2nd sample has pad.\n",
+"y=[x(1:2:xm-2),x(xm:2:length(x))]//decimation\n",
+"h=[x(1:1/3:length(x))]//step interpolated\n",
+"g=h;\n",
+"for i=2:3\n",
+"    g(i:3:length(g))=0;\n",
+"end\n",
+"//zero interpolated\n",
+"x1=1:3:3*length(x);\n",
+"s=interpln([x1;x],1:10)//linear interpolated"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4b: Decimation_and_Interpolation_of_Discrete_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.4 b,c.pg.no.17\n",
+"x=[3 4 5 6];\n",
+"xm=3;//denotes 3rd sample has pad\n",
+"xm=xm-1;//shifting\n",
+"g=[x(xm-2:-2:1),x(xm:2:length(x))]//decimation\n",
+"xm=3;\n",
+"h=[x(1:1/2:length(x))]//step interpolated"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4c: Decimation_and_Interpolation_of_Discrete_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.4c,pg.no.17\n",
+"x=[3 4 5 6];\n",
+"xm=3;\n",
+"xm=xm+1*(xm-1);//shift in pad due to interpolation\n",
+"xm=xm-2//normal shifting\n",
+"x1=[x(1:1/3:length(x))]//step interpolated\n",
+"xm=3;\n",
+"xm=xm+2*(xm-1)//shift in pad due to interpolation\n",
+"y=[x1(1:2:xm-2),x1(xm:2:length(x1))]//decimation"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.4d: Decimation_and_Interpolation_of_Discrete_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.4d,pg.no.17\n",
+"x=[2 4 6 8]\n",
+"xm=3;//denote 3rd sample has pad\n",
+"x1=[1 3 5 7]\n",
+"x2=interpln([x1;x],1:6)\n",
+"xm=xm+1*(xm-1);//shift in pad due to interpolation\n",
+"xm=xm-1//shift in pad due to delay\n",
+"y=[x2(2:2:xm-2),x2(xm:2:length(x2))]//decimation"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.5: Describing_Sequences_and_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.5,pg.no.20\n",
+"x=[1 2 4 8 16 32 64];\n",
+"y=[0 0 0 1 0 0 0];\n",
+"z=x.*y;\n",
+"a=0;\n",
+"for i=1:length(z)\n",
+"    a=a+z(i);\n",
+"end\n",
+"z,a//a=summation of z"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.6: Discrete_time_Harmonics_and_Periodicity.sci"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.6 pg.no.23\n",
+"function[p]=period(x)\n",
+"for i=2:length(x)\n",
+"    v=i\n",
+"    if (abs(x(i)-x(1))<0.00001)    \n",
+"        k=2\n",
+"        for j=i+1:i+i\n",
+"            if (abs(x(j)-x(k))<0.00001)   \n",
+"                v=v+1\n",
+"            end\n",
+"        k=k+1;      \n",
+"        end\n",
+"     end \n",
+"    if (v==(2*i)) then\n",
+"        break\n",
+"    end\n",
+"end\n",
+"p=i-1\n",
+"endfunction\n",
+"for i=1:60\n",
+"    x1(i)=cos((2*%pi*8*i)/25);\n",
+"end\n",
+"for i=1:60\n",
+"    x2(i)=exp(%i*0.2*i*%pi)+exp(-%i*0.3*i*%pi);\n",
+"end\n",
+"for i=1:45\n",
+"    x3(i)=2*cos((40*%pi*i)/75)+sin((60*%pi*i)/75);\n",
+"end\n",
+"period(x1)\n",
+"period(x2)\n",
+"period(x3)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.7: Aliasing_and_its_effects.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//example 2.7.pg.no.27\n",
+"f=100;\n",
+"s=240;\n",
+"s1=s;\n",
+"aliasfrequency(f,s)\n",
+"s=140;\n",
+"s1=s;\n",
+"aliasfrequency(f,s,s1)\n",
+"s=90;\n",
+"s1=s;\n",
+"aliasfrequency(f,s,s1)\n",
+"s=35;\n",
+"s1=s;\n",
+"aliasfrequency(f,s,s1)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 2.8: Signal_Reconstruction.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"f=100;\n",
+"s=210;\n",
+"s1=420;\n",
+"aliasfrequency(f,s,s1)\n",
+"s=140;\n",
+"aliasfrequency(f,s,s1)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/3-Response_of_Digital_Filters.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/3-Response_of_Digital_Filters.ipynb
new file mode 100644
index 0000000..c3ee5f6
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/3-Response_of_Digital_Filters.ipynb
@@ -0,0 +1,776 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 3: Response of Digital Filters"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.19a: Analytical_Evaluation_of_Discrete_Convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Analytical evaluation of Discrete Convolution\n",
+"clear;close;clc;\n",
+"max_limit=10;\n",
+"h=ones(1,max_limit);\n",
+"n2=0:length(h)-1;\n",
+"x=h;\n",
+"n1=-length(x)+1:0;\n",
+"y=convol(x,h);\n",
+"n=-length(x)+1:length(h)-1;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h)\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x)\n",
+"a.y_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"xtitle('output response','n','y[n]');\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.19b: Analytical_Evaluation_of_Discrete_Convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clear;close;clc;\n",
+"max_limit=10;\n",
+"for n=1:max_limit\n",
+"    h(n)=(0.4)^n;\n",
+"end\n",
+"n2=0:length(h)-1;\n",
+"for n=1:max_limit\n",
+"    x(n)=(0.8)^n;\n",
+"end\n",
+"n1=-length(x)+1:0;\n",
+"y=convol(x,h)\n",
+"n=-length(x)+1:length(h)-1;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h)\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x)\n",
+"a.y_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"xtitle('output response','n','y[n]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.19c: Analytical_Evaluation_of_Discrete_Convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Analytical Evaluation of Discrete convolution\n",
+"clear;close;clc;\n",
+"max_limit=5;\n",
+"h(1)=0;\n",
+"for n=2:max_limit\n",
+"    h(n)=0.8^n;\n",
+"end\n",
+"n2=0:length(h)-1;\n",
+"x=[0 ones(1:max_limit)]\n",
+"n1=-length(x)+1:0;\n",
+"y=convol(x,h);\n",
+"n=-length(x)+1:length(h)-1;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h)\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"a=gca();\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x)\n",
+"a.y_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"xtitle('output response','n','y[n]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.20a: Properties_of_Convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//properties of convolution\n",
+"x=[1 2 3 4 5];\n",
+"h=[1 zeros(1:5)];\n",
+"a=convol(x,h);\n",
+"b=convol(h,x);\n",
+"a==b"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.20b: Properties_of_Convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Convolution with Step Function\n",
+"x=[1 2 3 4 5];\n",
+"h=[ones(1:5)];\n",
+"a=convol(h,x);\n",
+"b(1)=a(1);\n",
+"for i=2:length(x)\n",
+"    b(i)=b(i-1)+x(i);\n",
+"end\n",
+"disp(a(1:length(x)),b,'Step Response is running sum of impulses can be seen below');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.21a: Convolution_of_finite_length_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//convolution of finite length signals\n",
+"clear;close;clc;\n",
+"max_limit=10;\n",
+"h=[1 2 2 3];\n",
+"n2=0:length(h)-1;\n",
+"x=[2 -1 3];\n",
+"n1=0:length(x)-1;\n",
+"y=convol(x,h);\n",
+"n=0:length(h)+length(x)-2;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h)\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"a=gca();\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x)\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',2);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"a.y_location='origin';\n",
+"xtitle('output response','n','y[n]');\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.21b: Convolution_of_finite_length_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clear;close;clc;\n",
+"max_limit=10;\n",
+"h=[2 5 0 4];\n",
+"n2=-2:length(h)-3;\n",
+"x=[4 1 3];\n",
+"n1=-1:length(x)-2;\n",
+"y=convol(x,h);\n",
+"n=-3:length(x)+length(h)-5;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h)\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"a=gca();\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x)\n",
+"a.y_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"xtitle('output response','n','y[n]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.21c: Convolution_of_finite_length_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clear;close;clc;\n",
+"max_limit=10;\n",
+"h=[1/2 1/2 1/2];\n",
+"n2=0:length(h)-1;\n",
+"x=[2 4 6 8 10];\n",
+"n1=0:length(x)-1;\n",
+"y=convol(x,h);\n",
+"n=0:length(x)+length(h)-2;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h);\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"a=gca();\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x);\n",
+"a.y_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"xtitle('output response','n','y[n]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.22: Convolution_of_finite_length_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"max_limit=10;\n",
+"h=[2 5 0 4];\n",
+"n2=0:length(h)-1;\n",
+"x=[4 1 3];\n",
+"n1=0:length(x)-1;\n",
+"y=convol(x,h);\n",
+"n=0:length(x)+length(h)-2;\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d3('gnn',n2,h)\n",
+"xtitle('impulse Response','n','h[n]');\n",
+"a.thickness=2;\n",
+"a.y_location='origin';\n",
+"a=gca();\n",
+"subplot(212);\n",
+"plot2d3('gnn',n1,x)\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"xtitle('input response','n','x[n]');\n",
+"xset('window',1);\n",
+"a=gca();\n",
+"plot2d3('gnn',n,y)\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"xtitle('output response','n','y[n]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.23: effect_of_Zero_Insertion.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//convolution by polynomial method\n",
+"x=[4 1 3];\n",
+"h=[2 5 0 4];\n",
+"z=%z;\n",
+"n=length(x)-1:-1:0;\n",
+"X=x*z^n';\n",
+"n1=length(h)-1:-1:0;\n",
+"H=h*z^n1';\n",
+"y=X*H\n",
+"//effect of zero insertion on convolution\n",
+"h=[2 0 5 0 0 0 4];\n",
+"x=[4 0 1 0 3];\n",
+"y=convol(x,h)\n",
+"//effect of zero padding on convolution\n",
+"h=[2 5 0 4 0 0];\n",
+"x=[4 1 3 0];\n",
+"y=convol(x,h)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.25: Stability_and_Causality.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//concepts based on stability and Causality\n",
+"function[]=stability(X)\n",
+"if (abs(roots(X))<1)\n",
+"    disp('given system is stable')\n",
+"else \n",
+"    disp('given system is not stable')\n",
+"end\n",
+"endfunction\n",
+"x=[1 -1/6 -1/6];\n",
+"z=%z;\n",
+"n=length(x)-1:-1:0;\n",
+"//characteristic eqn is\n",
+"X=x*(z)^n'\n",
+"stability(X)\n",
+"x=[1 -1];\n",
+"n=length(x)-1:-1:0;\n",
+"//characteristic eqn is\n",
+"X=x*(z)^n'\n",
+"stability(X)\n",
+"x=[1 -2 1];\n",
+"n=length(x)-1:-1:0;\n",
+"//characteristic eqn is\n",
+"X=x*(z)^n'\n",
+"stability(X)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.26: Response_to_Periodic_Inputs.sci"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Response of periodic inputs\n",
+"function[p]=period(x)\n",
+"for i=2:length(x)\n",
+"    v=i\n",
+"    if (abs(x(i)-x(1))<0.00001)    \n",
+"        k=2\n",
+"        for j=i+1:i+i\n",
+"            if (abs(x(j)-x(k))<0.00001)   \n",
+"                v=v+1\n",
+"            end\n",
+"        k=k+1;      \n",
+"        end\n",
+"     end \n",
+"    if (v==(2*i)) then\n",
+"        break\n",
+"    end\n",
+"end\n",
+"p=i-1\n",
+"endfunction\n",
+"x=[1 2 -3 1 2 -3 1 2 -3];\n",
+"h=[1 1];\n",
+"y=convol(x,h)\n",
+"y(1)=y(4);\n",
+"period(x)\n",
+"period(y)\n",
+"h=[1 1 1];\n",
+"y=convol(x,h)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.27: Periodic_Extension.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//to find periodic extension\n",
+"x=[1 5 2;0 4 3;6 7 0];\n",
+"y=[0 0 0];\n",
+"for i=1:3\n",
+"    for j=1:3\n",
+"        y(i)=y(i)+x(j,i);\n",
+"    end\n",
+"end\n",
+"y\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.28: System_Response_to_Periodic_Inputs.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//method of wrapping to fing convolution of periodic signal with one period\n",
+"x=[1 2 -3];\n",
+"h=[1 1];\n",
+"y1=convol(h,x)\n",
+"y1=[y1,zeros(5:9)]\n",
+"y2=[y1(1:3);y1(4:6);y1(7:9)];\n",
+"y=[0 0 0];\n",
+"for i=1:3\n",
+"    for j=1:3\n",
+"        y(i)=y(i)+y2(j,i);\n",
+"    end\n",
+"end\n",
+"y\n",
+"x=[2 1 3];\n",
+"h=[2 1 1 3 1];\n",
+"y1=convol(h,x)\n",
+"y1=[y1,zeros(8:9)]\n",
+"y2=[y1(1:3);y1(4:6);y1(7:9)];\n",
+"y=[0 0 0];\n",
+"for i=1:3\n",
+"    for j=1:3\n",
+"        y(i)=y(i)+y2(j,i);\n",
+"    end\n",
+"end\n",
+"y"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.29: Periodic_Convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//periodic or circular convolution\n",
+"x=[1 0 1 1];\n",
+"h=[1 2 3 1];\n",
+"y1=convol(h,x)\n",
+"y1=[y1,zeros(8:12)];\n",
+"y2=[y1(1:4);y1(5:8);y1(9:12)];\n",
+"y=[0 0 0 0];\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        y(i)=y(i)+y2(j,i);\n",
+"    end\n",
+"end\n",
+"y"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.30: Periodic_Convolution_by_Circulant_Matrix.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//periodic convolution by circulant matrix\n",
+"x=[1 0 2];\n",
+"h=[1;2;3];\n",
+"//generation of circulant matrix\n",
+"c(1,:)=x;\n",
+"for i=2:length(x)\n",
+"    c(i,:)=[x(length(x):length(x)-i),x(1:length(x)-i)]\n",
+"end\n",
+"c'"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.32: Deconvolution_By_polynomial_Division.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//deconvolution by polynomial division\n",
+"x=[2 5 0 4];\n",
+"y=[8 22 11 31 4 12];\n",
+"z=%z\n",
+"n=length(x)-1:-1:0;\n",
+"X=x*(z)^n'\n",
+"n1=length(y)-1:-1:0;\n",
+"Y=y*(z)^n1'\n",
+"h=Y/X"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.33: Autocorrelation_and_Cross_Correlation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//discrete auto correlation and cross correlation\n",
+"x=[2 5 0 4];\n",
+"h=[3 1 4];\n",
+"x1=x(length(x):-1:1)\n",
+"h1=h(length(h):-1:1)\n",
+"rxhn=convol(x,h1)\n",
+"rhxn=convol(x1,h)\n",
+"rhxn1=rhxn(length(rhxn):-1:1)\n",
+"//we observe that rhxn1=rxhn\n",
+"x=[3 1 -4];\n",
+"x1=x(length(x):-1:1)\n",
+"rxxn=convol(x,x1)\n",
+"//we observe that rxxn is even symmetric about origin"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.35: Periodic_Autocorrelation_and_Cross_Correlation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//discrete periodic auto correlation and cross correlation\n",
+"x=[2 5 0 4];\n",
+"h=[3 1 -1 2];\n",
+"x1=x(length(x):-1:1);\n",
+"h1=h(length(h):-1:1);\n",
+"rxhn=convol(x,h1)\n",
+"rhxn=convol(x1,h)\n",
+"rxxn=convol(x,x1)\n",
+"rhhn=convol(h,h1)\n",
+"y1=[rxhn,zeros(8:12)];\n",
+"y2=[y1(1:4);y1(5:8);y1(9:12)];\n",
+"y3=[rhxn,zeros(8:12)];\n",
+"y4=[y3(1:4);y3(5:8);y3(9:12)];\n",
+"y5=[rxxn,zeros(8:12)];\n",
+"y6=[y5(1:4);y5(5:8);y5(9:12)];\n",
+"y7=[rhhn,zeros(8:12)];\n",
+"y8=[y7(1:4);y7(5:8);y7(9:12)];\n",
+"rxhp=[0 0 0 0];\n",
+"rhxp=[0 0 0 0];\n",
+"rxxn=[0 0 0 0];\n",
+"rhhp=[0 0 0 0];\n",
+"for i=1:4\n",
+"     for j=1:3\n",
+"        rhxp(i)=rhxp(i)+y4(j,i);\n",
+"        rxhp(i)=rxhp(i)+y2(j,i);\n",
+"        rxxn(i)=rxxn(i)+y6(j,i);\n",
+"        rhhp(i)=rhhp(i)+y8(j,i);\n",
+"    end\n",
+"end\n",
+"rxhp\n",
+"rhxp\n",
+"rxxn\n",
+"rhhp"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 3.5: FIR_filter_response.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Response of non-recursive Filters\n",
+"for i=1:4\n",
+"    x(i)=0.5^i;\n",
+"end\n",
+"x1=[0;1;x(1:2)]\n",
+"for i=1:4\n",
+"     y(i)=2*x(i)-3*x1(i);\n",
+"end     \n",
+"y(1),y(2)"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/4-z_Transform_Analysis.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/4-z_Transform_Analysis.ipynb
new file mode 100644
index 0000000..13f9d3d
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/4-z_Transform_Analysis.ipynb
@@ -0,0 +1,290 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 4: z Transform Analysis"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.10: Inverse_Transform_of_sequences.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//inverse transform of sequences\n",
+"//(a)X(z)=3z^-1+5z^-3+2z^-4\n",
+"z=%z;\n",
+"X1=[3*z^-1;0;5*z^-3;2*z^-4];\n",
+"n1=1:4;\n",
+"ZI=z^n1';\n",
+"x1=numer(X1.*ZI);\n",
+"disp(x1,'x[n]=');\n",
+"//(b)X(z)=2z^2-5z+5z^-1-2z^-2\n",
+"X2=[2*z^2;-5*z;0;5*z^-1;-2*z^-2];\n",
+"n2=-2:2;\n",
+"ZI=z^n2';\n",
+"x2=numer(X2.*ZI);\n",
+"disp(x2,'x[n]=');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.11: Inverse_Transform_by_Long_Division.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//inverse transform by long division\n",
+"z=%z;\n",
+"x=ldiv(z-4,1-z+z^2,5)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.12: Inverse_transform_of_Right_sided_sequences.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//inverse z transforms from standard transforms\n",
+"z=%z;\n",
+"xz=z/((z-0.5)*(z-0.25));\n",
+"yz=xz/z;\n",
+"pfss(yz)\n",
+"//hence x[n]=-4(0.25)^n*un+4(0.5)^n*un;\n",
+"xz=1/((z-0.5)*(z-0.25));\n",
+"yz=xz/z;\n",
+"pfss(yz)\n",
+"//hence x[n]=-4(0.25)^n-1*u[n-1]+4(0.5)^n-1*u[n-1];\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.1b: z_transform_of_finite_length_sequences.sci"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"function[za]=ztransfer(sequence,n)\n",
+"    z=poly(0,'z','r')\n",
+"    za=sequence*(1/z)^n'\n",
+"endfunction\n",
+"x1=[2 1 -5 4];\n",
+"n=-1:length(x1)-2;\n",
+"ztransfer(x1,n)    "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.20: z_Transform_of_Switched_periodic_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//z transform of switched periodic signals\n",
+"z=%z;\n",
+"//sol. for 4.20a\n",
+"x1=[0 1 2];\n",
+"n=0:2;\n",
+"N=3;\n",
+"x1z=x1*(1/z)^n'\n",
+"xz=x1z/(1-z^-N)\n",
+"//sol.for 4.20b\n",
+"x1=[0 1 0 -1];\n",
+"n=0:3;\n",
+"N=4;\n",
+"x1z=x1*(1/z)^n'\n",
+"xz=x1z/(1-z^-N)\n",
+"//sol.for 4.20c\n",
+"xz=(2+z^-1)/(1-z^-3);\n",
+"x1z=numer(xz)\n",
+"//thus first period of xn is [2 1 0]\n",
+"//sol.for 4.20d\n",
+"xz=(z^-1-z^-4)/(1-z^-6);\n",
+"x1z=numer(xz)\n",
+"//thus first period of xn is [0 1 0 0 -1 0]"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.4a: Pole_Zero_Plots.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Pole-Zero plots\n",
+"z=%z;\n",
+"az=2*z*(z+1);\n",
+"bz=(z-1/3)*((z^2)+1/4)*((z^2)+4*z+5);\n",
+"poles=roots(bz)\n",
+"zeroes=roots(az)\n",
+"h=az/bz\n",
+"plzr(h)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.4b: Pole_Zero_plots.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Pole-Zero plots\n",
+"z=%z;\n",
+"az=z^4+4.25*z^2+1;\n",
+"bz=z^4;\n",
+"poles=roots(bz)\n",
+"zeroes=roots(az)\n",
+"h=az/bz\n",
+"plzr(h)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.8: Stability_of_Recursive_Filters.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//stability of recursive filter\n",
+"//for roc:/z/>/a/ \n",
+"a=input('enter the value of alpha')\n",
+"z=%z;\n",
+"H=z/(z-a);\n",
+"if (abs(a)<1)\n",
+"    disp('system is stable')\n",
+"else\n",
+"    disp('system is not stable')\n",
+" end\n",
+" //for roc:/z/</a/\n",
+" if (abs(a)>1)\n",
+"    disp('system is stable')\n",
+"else\n",
+"    disp('system is not stable')\n",
+" end\n",
+"        "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 4.9: Inverse_Systems.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//inverse systems\n",
+"z=%z;\n",
+"H=(1+2*(z^(-1)))/(1+3*(z^(-1)));\n",
+"//inverse of H is\n",
+"H1=1/H\n",
+"H=1+2*(z^(-1))+3*(z^(-2));\n",
+"H1=1/H"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/5-Frequency_Domain_Analysis.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/5-Frequency_Domain_Analysis.ipynb
new file mode 100644
index 0000000..e5ef6e2
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/5-Frequency_Domain_Analysis.ipynb
@@ -0,0 +1,742 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 5: Frequency Domain Analysis"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.10a: System_Representation_in_various_forms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//System Representation in various forms\n",
+"a=0.8;b=2;\n",
+"n=0:50;\n",
+"h=b*(a^n);\n",
+"//Discrete-Time Fourier transform\n",
+"K=500;\n",
+"k=0:1:K;\n",
+"w=%pi*k/K;\n",
+"H=h*exp(-%i*n'*w);\n",
+"//caluculation of phase and magnitude of h(z)\n",
+"[phase_H,m]=phasemag(H);\n",
+"H=abs(H);\n",
+"subplot(2,1,1);\n",
+"plot2d(w/%pi,H);\n",
+"xlabel('Frequency in radians')\n",
+"ylabel('abs(H)')\n",
+"title('magnitude Response')\n",
+"subplot(2,1,2)\n",
+"plot2d(w/%pi,phase_H)\n",
+"xlabel('Frequency in Radians');\n",
+"ylabel('<(H)')\n",
+"title('Phase Response')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.10b: System_Representation_in_various_forms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//System Representation in various forms\n",
+"a=0.6;b=1;\n",
+"n=0:50;\n",
+"h=b*(a^n);\n",
+"//Discrete-Time Fourier transform\n",
+"K=500;\n",
+"k=0:1:K;\n",
+"w=%pi*k/K;\n",
+"H=h*exp(-%i*n'*w);\n",
+"//caluculation of phase and magnitude of h(z)\n",
+"[phase_H,m]=phasemag(H);\n",
+"H=abs(H);\n",
+"subplot(2,1,1);\n",
+"plot2d(w/%pi,H);\n",
+"xlabel('Frequency in radians')\n",
+"ylabel('abs(H)')\n",
+"title('magnitude Response')\n",
+"subplot(2,1,2)\n",
+"plot2d(w/%pi,phase_H)\n",
+"xlabel('Frequency in Radians');\n",
+"ylabel('<(H)')\n",
+"title('Phase Response')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.1c: DTFT_from_Defining_Relation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT of x[n]=(a)^n*u[n]\n",
+"clear;\n",
+"clc;close;\n",
+"//DTS signal\n",
+"a1=0.5;\n",
+"a2=-0.5;\n",
+"max_limit=10;\n",
+"for n=0:max_limit-1\n",
+"  x1(n+1)=(a1^n);\n",
+"  x2(n+1)=(a2^n);\n",
+"end\n",
+"n=0:max_limit-1;\n",
+"//discrete time fourier transform\n",
+"wmax=2*%pi;\n",
+"K=4;\n",
+"k=0:(K/1000):K;\n",
+"W=k*wmax/K;\n",
+"x1=x1'\n",
+"x2=x2'\n",
+"XW1=x1*exp(%i*n'*W);\n",
+"XW2=x2*exp(%i*n'*W);\n",
+"XW1_Mag=abs(XW1);\n",
+"XW2_Mag=abs(XW2);\n",
+"W=[-mtlb_fliplr(W),W(2:1001)];//omega form\n",
+"XW1_Mag=[mtlb_fliplr(XW1_Mag),XW1_Mag(2:1001)];\n",
+"XW2_Mag=[mtlb_fliplr(XW2_Mag),XW2_Mag(2:1001)];\n",
+"[XW1_phase,db]=phasemag(XW1);\n",
+"[XW2_phase,db]=phasemag(XW2);\n",
+"XW1_phase=[-mtlb_fliplr(XW1_phase),XW1_phase(2:1001)];\n",
+"XW2_phase=[-mtlb_fliplr(XW2_phase),XW2_phase(2:1001)];\n",
+"\n",
+"//plot for a>0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x1)\n",
+"xtitle('Discrete time sequencex[n] a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d3(W,XW1_Mag);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW1_phase);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"//plot for a<0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x2);\n",
+"xtitle('Discrete Time sequence x[n] for a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_Mag);\n",
+"title('Magnitude Response abs(X(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_phase);\n",
+"title('phase Response<(X(jw))')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.3a: Some_DTFT_pairs_using_properties.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT of x[n]=n*(a)^n*u[n]\n",
+"clear;\n",
+"clc;close;\n",
+"//DTS signal\n",
+"a1=0.5;\n",
+"a2=-0.5;\n",
+"max_limit=10;\n",
+"for n=0:max_limit-1\n",
+"  x1(n+1)=n*(a1^n);\n",
+"  x2(n+1)=n*(a2^n);\n",
+"end\n",
+"n=0:max_limit-1;\n",
+"//discrete time fourier transform\n",
+"wmax=2*%pi;\n",
+"K=4;\n",
+"k=0:(K/1000):K;\n",
+"W=k*wmax/K;\n",
+"x1=x1';\n",
+"x2=x2';\n",
+"XW1=x1*exp(%i*n'*W);\n",
+"XW2=x2*exp(%i*n'*W);\n",
+"XW1_Mag=abs(XW1);\n",
+"XW2_Mag=abs(XW2);\n",
+"W=[-mtlb_fliplr(W),W(2:1001)];//omega form\n",
+"XW1_Mag=[mtlb_fliplr(XW1_Mag),XW1_Mag(2:1001)];\n",
+"XW2_Mag=[mtlb_fliplr(XW2_Mag),XW2_Mag(2:1001)];\n",
+"[XW1_phase,db]=phasemag(XW1);\n",
+"[XW2_phase,db]=phasemag(XW2);\n",
+"XW1_phase=[-mtlb_fliplr(XW1_phase),XW1_phase(2:1001)];\n",
+"XW2_phase=[-mtlb_fliplr(XW2_phase),XW2_phase(2:1001)];\n",
+"\n",
+"//plot for a>0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x1)\n",
+"xtitle('Discrete time sequencex[n] a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d3(W,XW1_Mag);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW1_phase);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"//plot for a<0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x2);\n",
+"xtitle('Discrete Time sequence x[n] for a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_Mag);\n",
+"title('Magnitude Response abs(X(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_phase);\n",
+"title('phase Response<(X(jw))')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.3b: Some_DTFT_pairs_using_properties.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT of x[n]=n*(a)^n*u[n]\n",
+"clear;\n",
+"clc;close;\n",
+"//DTS signal\n",
+"a1=0.5;\n",
+"a2=-0.5;\n",
+"max_limit=10;\n",
+"for n=0:max_limit-1\n",
+"  x1(n+1)=(n+1)*(a1^n);\n",
+"  x2(n+1)=(n+1)*(a2^n);\n",
+"end\n",
+"n=0:max_limit-1;\n",
+"//discrete time fourier transform\n",
+"wmax=2*%pi;\n",
+"K=4;\n",
+"k=0:(K/1000):K;\n",
+"W=k*wmax/K;\n",
+"x1=x1';\n",
+"x2=x2';\n",
+"XW1=x1*exp(%i*n'*W);\n",
+"XW2=x2*exp(%i*n'*W);\n",
+"XW1_Mag=abs(XW1);\n",
+"XW2_Mag=abs(XW2);\n",
+"W=[-mtlb_fliplr(W),W(2:1001)];//omega form\n",
+"XW1_Mag=[mtlb_fliplr(XW1_Mag),XW1_Mag(2:1001)];\n",
+"XW2_Mag=[mtlb_fliplr(XW2_Mag),XW2_Mag(2:1001)];\n",
+"[XW1_phase,db]=phasemag(XW1);\n",
+"[XW2_phase,db]=phasemag(XW2);\n",
+"XW1_phase=[-mtlb_fliplr(XW1_phase),XW1_phase(2:1001)];\n",
+"XW2_phase=[-mtlb_fliplr(XW2_phase),XW2_phase(2:1001)];\n",
+"\n",
+"//plot for a>0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x1)\n",
+"xtitle('Discrete time sequencex[n] a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d3(W,XW1_Mag);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW1_phase);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"//plot for a<0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x2);\n",
+"xtitle('Discrete Time sequence x[n] for a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_Mag);\n",
+"title('Magnitude Response abs(X(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_phase);\n",
+"title('phase Response<(X(jw))')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.3d: Some_DTFT_pairs_using_properties.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT of x[n]=a^abs(n)\n",
+"a=0.5;\n",
+"n=-9:9;\n",
+"x=a^abs(n);\n",
+"//Discrete time Fourier Transform\n",
+"k=0:(4/1000):4;\n",
+"w=(2*%pi*k)/4;\n",
+"xw=x*exp(%i*n'*w);\n",
+"xw_mag=real(xw);\n",
+"w=[-mtlb_fliplr(xw_mag),w(2:1001)];\n",
+"xw_mag=[mtlb_fliplr(xw_mag),xw_mag(2:1001)];\n",
+"figure\n",
+"subplot(2,1,1);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d3('gnn',n,x);\n",
+"xtitle('discrete time sequence x[n]');\n",
+"subplot(2,1,2);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(w,xw_mag);\n",
+"title('discrete time fourier transform x(exp(jw))');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.3e: Some_DTFT_pairs_using_properties.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT of x[n]=n*(a)^n*u[n]\n",
+"clear;\n",
+"clc;close;\n",
+"//DTS signal\n",
+"a1=0.5;\n",
+"a2=-0.5;\n",
+"max_limit=10;\n",
+"for n=0:max_limit-1\n",
+"  x1(n+1)=4*(a1^(n+3));\n",
+"  x2(n+1)=4*(a2^(n+3));\n",
+"end\n",
+"n=0:max_limit-1;\n",
+"//discrete time fourier transform\n",
+"wmax=2*%pi;\n",
+"K=4;\n",
+"k=0:(K/1000):K;\n",
+"W=k*wmax/K;\n",
+"x1=x1';\n",
+"x2=x2';\n",
+"XW1=x1*exp(%i*n'*W);\n",
+"XW2=x2*exp(%i*n'*W);\n",
+"XW1_Mag=abs(XW1);\n",
+"XW2_Mag=abs(XW2);\n",
+"W=[-mtlb_fliplr(W),W(2:1001)];//omega form\n",
+"XW1_Mag=[mtlb_fliplr(XW1_Mag),XW1_Mag(2:1001)];\n",
+"XW2_Mag=[mtlb_fliplr(XW2_Mag),XW2_Mag(2:1001)];\n",
+"[XW1_phase,db]=phasemag(XW1);\n",
+"[XW2_phase,db]=phasemag(XW2);\n",
+"XW1_phase=[-mtlb_fliplr(XW1_phase),XW1_phase(2:1001)];\n",
+"XW2_phase=[-mtlb_fliplr(XW2_phase),XW2_phase(2:1001)];\n",
+"\n",
+"//plot for a>0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x1)\n",
+"xtitle('Discrete time sequencex[n] a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d3(W,XW1_Mag);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW1_phase);\n",
+"title('magnitude Response abs(exp(jw))')\n",
+"//plot for a<0\n",
+"figure\n",
+"subplot(3,1,1);\n",
+"plot2d3('gnn',n,x2);\n",
+"xtitle('Discrete Time sequence x[n] for a>0')\n",
+"subplot(3,1,2);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_Mag);\n",
+"title('Magnitude Response abs(X(jw))')\n",
+"subplot(3,1,3);\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d(W,XW2_phase);\n",
+"title('phase Response<(X(jw))')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.4: DTFT_of_periodic_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTfT of periodic signals\n",
+"x=[3 2 1 2];//one period of signal\n",
+"n=0:3;\n",
+"k=0:3;\n",
+"x1=x*exp(%i*n'*2*k*%pi/4)\n",
+"dtftx=abs(x1)\n",
+"x=[3 2 1 2 3 2 1 2 3];\n",
+"n=-4:4;\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"a.x_location='origin';\n",
+"plot2d3('gnn',n,x);\n",
+"xtitle('discrete periodic time signal');\n",
+"x2=[dtftx dtftx 8];\n",
+"a=gca();\n",
+"xset('window',1);\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d3('gnn',n,x2);\n",
+"xtitle('DTFT of discrete periodic signal');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.5: The_DFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"x=[1 0 2 0 3];//one period of signal\n",
+"n=0:4;\n",
+"k=0:4;\n",
+"x1=x*exp(%i*n'*2*k*%pi/4)\n",
+"DTFTx=abs(x1)\n",
+"DFT=dft(x,-1)\n",
+"DFS=DFT/5"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.7: Frequency_Response_of_Recursive_Filter.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"a=0.5;b=1;\n",
+"n=0:50;\n",
+"h=b*(a^n);\n",
+"//Discrete-Time Fourier transform\n",
+"K=500;\n",
+"k=-250:1:250;\n",
+"w=%pi*k/K;\n",
+"H=h*exp(-%i*n'*w);\n",
+"//caluculation of phase and magnitude of h(z)\n",
+"[phase_H,m]=phasemag(H);\n",
+"H=abs(H);\n",
+"a=gca();\n",
+"subplot(2,1,1);\n",
+"a.y_location='origin';\n",
+"plot2d(w/%pi,H);\n",
+"xlabel('Frequency in radians')\n",
+"ylabel('abs(H)')\n",
+"title('magnitude Response')\n",
+"subplot(2,1,2);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(w/(2*%pi),phase_H)\n",
+"xlabel('Frequency in Radians');\n",
+"ylabel('<(H)')\n",
+"title('Phase Response'))"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.8a: The_DTFT_in_System_Analysis.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT in system analysis\n",
+"a=0.5;b=1;\n",
+"n=0:50;\n",
+"h=b*(a^n);\n",
+"//Discrete-Time Fourier transform\n",
+"K=500;\n",
+"k=0:1:K;\n",
+"w=%pi*k/K;\n",
+"H=h*exp(-%i*n'*w);\n",
+"//x[n] is given as (a)^n*u[n]\n",
+"xw=h*exp(-%i*n'*w);\n",
+"for i=1:501\n",
+"    y(i)=H(i)*xw(i);\n",
+"end\n",
+"[phase_y,m]=phasemag(y);\n",
+"y=real(y);\n",
+"subplot(2,1,1)\n",
+"plot2d(w/%pi,y);\n",
+"xlabel('Frequency in radians')\n",
+"ylabel('abs(y)')\n",
+"title('magnitude Response')\n",
+"subplot(2,1,2)\n",
+"plot2d(w/%pi,phase_y)\n",
+"xlabel('Frequency in Radians');\n",
+"ylabel('<(y)')\n",
+"title('Phase Response')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.8b: The_DTFT_in_System_Analysis.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"a=0.5;b=1;\n",
+"n=0:50;\n",
+"h=4*(a^n);\n",
+"//Discrete-Time Fourier transform\n",
+"K=500;\n",
+"k=0:1:K;\n",
+"w=%pi*k/K;\n",
+"H=h*exp(-%i*n'*w);\n",
+"//x[n] is given as (a)^n*u[n]\n",
+"x=4*[ones(1:51)];\n",
+"xw=x*exp(%i*n'*w);\n",
+"for i=1:501\n",
+"    y(i)=H(i)*xw(i);\n",
+"end\n",
+"[phase_y,m]=phasemag(y);\n",
+"y=real(y);\n",
+"subplot(2,1,1);\n",
+"plot2d(w/%pi,y);\n",
+"xlabel('Frequency in radians')\n",
+"ylabel('abs(y)')\n",
+"title('magnitude Response')\n",
+"subplot(2,1,2)\n",
+"plot2d(w/%pi,phase_y)\n",
+"xlabel('Frequency in Radians');\n",
+"ylabel('<(y)')\n",
+"title('Phase Response')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.9a: DTFT_and_steady_state_response.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT and steady state response \n",
+"a=0.5,b=1;F=0.25;\n",
+"n=0:(5/1000):5;\n",
+"h=(a^n);\n",
+"x=10*cos(0.5*%pi*n'+%pi/3);\n",
+"H=h*exp(-%i*n'*F);\n",
+"Yss=H*x;\n",
+"[phase_Yss,m]=phasemag(Yss);\n",
+"Yss=real(Yss);\n",
+"subplot(2,1,1)\n",
+"plot2d(n,Yss);\n",
+"xlabel('Frequency in radians')\n",
+"ylabel('abs(Yss)')\n",
+"title('magnitude Response')\n",
+"subplot(2,1,2)\n",
+"plot2d(n,phase_Yss)\n",
+"xlabel('Frequency in Radians');\n",
+"ylabel('<(y)')\n",
+"title('Phase Response')"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 5.9b: DTFT_and_steady_state_response.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT and steady state response \n",
+"a=0.8,b=1;F=0;\n",
+"n=0:50;\n",
+"h=(a^n);\n",
+"x=4*[ones(1:10)];\n",
+"H=h*exp(-%i*n'*F)\n",
+"Yss=H*x"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/6-Filter_Concepts.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/6-Filter_Concepts.ipynb
new file mode 100644
index 0000000..aa52a00
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/6-Filter_Concepts.ipynb
@@ -0,0 +1,306 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 6: Filter Concepts"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.1: The_Minimum_Phase_Concept.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//The minimum phase concept\n",
+"z=%z;\n",
+"F=0:(0.5/400):0.5;\n",
+"z=exp(%i*2*%pi*F);\n",
+"for i=1:401\n",
+"H1Z(i)=((z(i)-1/2)*(z(i)-1/4))/((z(i)-1/3)*(z(i)-1/5));\n",
+"end\n",
+"for i=1:401\n",
+"H2Z(i)=(((-1/2)*z(i)+1)*(z(i)-1/4))/((z(i)-1/3)*(z(i)-1/5));\n",
+"end\n",
+"for i=1:401\n",
+"H3Z(i)=(((-1/2)*z(i)+1)*((-1/4)*z(i)+1))/((z(i)-1/3)*(z(i)-1/5));\n",
+"end\n",
+"[phase_H1Z,m]=phasemag(H1Z);\n",
+"[phase_H2Z,m]=phasemag(H2Z);\n",
+"[phase_H3Z,m]=phasemag(H3Z);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"xlabel('Digital Frequency F');\n",
+"ylabel('phase[degrees]');\n",
+"xtitle('phase of three filters');\n",
+"plot2d(F,phase_H1Z,rect=[0,-200,0.5,200]);\n",
+"plot2d(F,phase_H2Z,rect=[0,-200,0.5,200]);\n",
+"plot2d(F,phase_H3Z,rect=[0,-200,0.5,200]);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.4: Linear_Phase_Filters.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//linear phase filters\n",
+"z=%z\n",
+"H1Z=((z^3)+2*(z^2)+2*z+1)/(z^3);\n",
+"//from pole zero diagram its not a linear phase filter\n",
+"H2Z=(z^4+4.25*z^2+1)/(z^4);\n",
+"xset('window',1);\n",
+"plzr(H2Z);\n",
+"//from pole zero diagram and LPF\n",
+"// characteristics its a linear phase filter\n",
+"H3Z=((z^4+2.5*z^3-2.5*z-1)/(z^4));\n",
+"xset('window',2);\n",
+"plzr(H3Z);\n",
+"//from pole zero diagram and LPF\n",
+"// characteristics its a linear phase filter"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.6: Frequency_Response_and_Filter_characteristics.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Frequency Response and filter characteristics\n",
+"z=%z;\n",
+"F=0:(0.5/200):0.5;\n",
+"z=exp(%i*2*%pi*F);\n",
+"H1=(1/3)*(z+1+z^-1);\n",
+"H2=(z/4)+(1/2)+(1/4)*(z^-1);\n",
+"H1=abs(H1);\n",
+"H2=abs(H2);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"subplot(211);\n",
+"plot2d(F,H1);\n",
+"xlabel('Digital frequency F');\n",
+"ylabel('impuse function H1(f)');\n",
+"subplot(212);\n",
+"plot2d(F,H2);\n",
+"xlabel('Digital frequency F');\n",
+"ylabel('impuse function H1(f)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.7a: Filters_and_Pole_Zero_Plots.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"z=%z;\n",
+"s=%s;\n",
+"F=0:(0.5/400):0.5;\n",
+"s=exp(%i*2*%pi*F);\n",
+"H1Z=(z^4+1)/(z^4+1.6982*z^2+0.7210);\n",
+"for i=1:401\n",
+"    H1(i)=(s(i)^4+1)/(s(i)^4+1.6982*s(i)^2+0.7210);\n",
+"end\n",
+"H1=abs(H1);\n",
+"plzr(H1Z);\n",
+"a=gca();\n",
+"xset('window',1);\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(F,H1)\n",
+"xlabel('Digital frequency F');\n",
+"ylabel('magnitude');\n",
+"xtitle('Magnitude spectrum of bandpass filter');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.7b: Filters_and_Pole_Zero_Plots.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"z=%z;\n",
+"s=%s;\n",
+"F=0:(0.5/400):0.5;\n",
+"s=exp(%i*2*%pi*F);\n",
+"H1Z=(z^2+1-0.618*z)/(z^2-0.5857*z+0.898);\n",
+"for i=1:401\n",
+"    H1(i)=(s(i)^2+1-0.618*s(i))/(s(i)^2-0.5857*s(i)+0.898);\n",
+"end\n",
+"H1=abs(H1);\n",
+"plzr(H1Z);\n",
+"a=gca();\n",
+"xset('window',1);\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(F,H1)\n",
+"xlabel('Digital frequency F');\n",
+"ylabel('magnitude');\n",
+"xtitle('Magnitude spectrum of bandpass filter');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.8: Digital_resonator_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Digital Resonator design with peak gain 50 HZ \n",
+"//and 3 db bandwidth of 6HZ at sampling of 300 HZ\n",
+"clf();\n",
+"s=%s;\n",
+"F=0:150;\n",
+"f=F/300;\n",
+"s=exp(%i*2*%pi*f);\n",
+"for i=1:151\n",
+"    H1(i)=(0.1054*(s(i)^2))/(s(i)^2-0.9372*s(i)+0.8783);\n",
+"end\n",
+"H1=abs(H1);\n",
+"H2=H1(40:60);\n",
+"F1=40:60;\n",
+"f1=F1/300;\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(F,H1)\n",
+"xlabel('Analog frequency F');\n",
+"ylabel('magnitude');\n",
+"xtitle('Magnitude spectrum of digital resonator with peak 50HZ');\n",
+"xset('window',1);\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(F1,H2)\n",
+"xlabel('Analog frequency F');\n",
+"ylabel('magnitude');\n",
+"xtitle('passband detail');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 6.9: Periodic_Notch_Filter_Desig.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Periodic notch filter design at 60 HZ and sampling frequency 300HZ\n",
+"z=%z;\n",
+"f=0:(0.5/400):0.5;\n",
+"z1=exp(%i*2*%pi*f);\n",
+"for i=1:401\n",
+"    H1Z(i)=(z1(i)^5-1)/((z1(i)^5)-(0.9^5));\n",
+"    H2Z(i)=(z1(i)^5-1)/((z1(i)^5)-(0.99^5));\n",
+"end\n",
+"H1Z=abs(H1Z);\n",
+"H2Z=abs(H2Z);\n",
+"N1z=(1-z^-5)/(1-z^-1);\n",
+"H3z=(N1z)/(horner(N1z,z/0.9));\n",
+"H4z=(N1z)/(horner(N1z,z/0.99));\n",
+"H3z=horner(H3z,z1);\n",
+"H4z=horner(H4z,z1);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"a.y_location='origin';\n",
+"plot2d(f,H1Z);\n",
+"plot2d(f,H2Z);\n",
+"xlabel('Digital frequency f');\n",
+"ylabel('magnitude');\n",
+"xtitle('Periodic Notch Filter N=5,R=0.9,0.99');\n",
+"xset('window',1);\n",
+"plot2d(f,H3z);\n",
+"plot2d(f,H4z);\n",
+"xlabel('Digital frequency f');\n",
+"ylabel('magnitude');\n",
+"xtitle('Notch Filter that also passes DC N=5,R=0.9,0.99');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/7-Digital_Processing_of_Analog_Signals.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/7-Digital_Processing_of_Analog_Signals.ipynb
new file mode 100644
index 0000000..ab88b1e
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/7-Digital_Processing_of_Analog_Signals.ipynb
@@ -0,0 +1,406 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 7: Digital Processing of Analog Signals"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.10: ADC_considerations.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//ADC considerations\n",
+"//(a)Aperture time TA\n",
+"B=12;\n",
+"fo=15000;//band limited frquency\n",
+"TAm=(1/((2^B)))/(%pi*fo);\n",
+"TAm=TAm*10^9\n",
+"//Hence TA must satisfy TA<=TAm nano sec\n",
+"//(b)conversion time of quantizer\n",
+"TA=4*10^-9;\n",
+"TH=10*10^-6;//hold time\n",
+"S=30*10^3;\n",
+"TCm=1/S-TA-TH;\n",
+"TCm=TCm*10^6\n",
+"//Hence TC must satisfy TC<=TCm micro sec\n",
+"//(c)Holding capacitance C\n",
+"Vo=10;\n",
+"TH=10*10^-6;\n",
+"B=12;\n",
+"R=10^6;//input resistance\n",
+"delv=Vo/(2^(B+1));\n",
+"Cm=(Vo*TH)/(R*delv);\n",
+"Cm=Cm*10^9\n",
+"//Hence C must satisfy C>=Cm nano farad"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.11: Anti_Aliasing_Filter_Considerations.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Anti Aliasing filter considerations\n",
+"//minimum stop band attenuation As\n",
+"B=input('enter no. of bits');//no. of samples\n",
+"n=input('enter band width in KHZ');\n",
+"As=20*log10(2^B*sqrt(6))\n",
+"//nomalised frequency\n",
+"Vs=(10^(0.1*As)-1)^(1/(2*n))\n",
+"fp=4;//pass edge frequency\n",
+"fs=Vs*fp//stop band frquency\n",
+"S=2*fs//sampling frequency\n",
+"fa=S-fp//aliaed frequency\n",
+"Va=fa/fp;\n",
+"//Attenuation at aliased frequency\n",
+"Aa=10*log10(1+Va^(2*n))"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.12: Anti_Imaging_Filter_Considerations.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Anti Imaging Filter considerations\n",
+"Ap=0.5;//passband attenuation\n",
+"fp=20;//passband edge frequency\n",
+"As=60;//stopband attenuation\n",
+"S=42.1;\n",
+"fs=S-fp;//stopband edge frequency\n",
+"e=sqrt(10^(0.1*Ap)-1);\n",
+"e1=sqrt(10^(0.1*As)-1);\n",
+"n=(log10(e1/e))/(log10(fs/fp));\n",
+"n=ceil(n)//design of nth order butworth filter\n",
+"//(b)Assuming Zero-order hold sampling\n",
+"S1=176.4;\n",
+"fs1=S1-fp;\n",
+"Ap=0.316;\n",
+"e2=sqrt(10^(0.1*Ap)-1);\n",
+"n1=(log10(e1/e2))/(log(fs1/fp));//new order of butworth filter\n",
+"n1=ceil(n1)\n",
+"f=0:100;\n",
+"x=abs(sinc(f*%pi/S));\n",
+"f1=0:500;\n",
+"x1=abs(sinc(f1*%pi/S1));\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d(f,x);\n",
+"xtitle('spectra under normal sampling condition','f(kHZ)','sinc(f/s1)');\n",
+"subplot(212);\n",
+"plot2d(f1,x1);\n",
+"xtitle('spectra under over sampling condition','f(kHZ)','sinc(f/s1)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.3: Sampling_oscilloscope.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Sampling Oscilloscope Concepts\n",
+"fo=100;a=50;\n",
+"s=(a-1)*fo/a;\n",
+"B=100-s;\n",
+"i=s/(2*B);\n",
+"i=ceil(i);\n",
+"disp(i,'The sampling frequency can at max divided by i');\n",
+"disp(s,2*B,'range of sampling rate is between s and 2*B');\n",
+"fo1=100;\n",
+"a=50;\n",
+"s1=(a-1)*fo1/a;\n",
+"B1=400-4*s1;\n",
+"j=s1/(2*B1);\n",
+"j=ceil(j);\n",
+"disp(j,'The sampling frequency can at max divided by j');\n",
+"disp(s1,2*B1,'range of sampling rate is between s1 and 2*B1');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.4: Sampling_of_Band_pass_signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//sampling of bandpass signals\n",
+"fc=4;fl=6;\n",
+"B=fl-fc;\n",
+"xt=[0 1 2 1];\n",
+"xtt=[0 1 2];\n",
+"a=0;b=1;c=2;\n",
+"xta=[xt];\n",
+"xtb=[0 0 2 1 0];\n",
+"xtc=[0 0 0 2 1 0];\n",
+"xt1=[xta xta xta]; \n",
+"xt2=[xtb xtb(length(xtb):-1:2) xtb(2:length(xtb)) xtb(length(xtb):-1:2)];\n",
+"xt3=[xtc(length(xtc):-1:2) xtc(3:length(xtc)) zeros(1:7) xtc(length(xtc):-1:2) xtc(3:length(xtc))];\n",
+"f1=0:length(xt1)-1;\n",
+"f2=[0 1 1.001 2:6 6.001 7 7.001 8:12 12.001];\n",
+"f3=[-10:-8 -7.99 -7:-6 -5.99 -5:6 6.01 7:8 8.01 9:10];\n",
+"subplot(211);\n",
+"plot2d(f1,xt1);\n",
+"xtitle('spectrum of signal sampled at 4KHZ');\n",
+"subplot(212);\n",
+"plot2d(f2,xt2);\n",
+"xtitle('spectrum of signal sampled at 7KHZ');\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.y_location='origin'\n",
+"plot2d(f3,xt3);\n",
+"xtitle('spectrum of signal sampled at 14KHZ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.6: Signal_Reconstruction_from_Samples.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//signal reconstruction from samples\n",
+"//(a)By step interpolation method\n",
+"x=[-1 2 3 2];\n",
+"t=2.5;\n",
+"ts=1;\n",
+"t1=ceil(t);\n",
+"t2=floor(t);\n",
+"x1t=x(t2)\n",
+"//(b)By linear interpolation method\n",
+"x2t=(x(t1)+x(t2))/2\n",
+"//(c)By sinc interpolation method\n",
+"x3t=0;x1=[1 2 3 4];\n",
+"for k=1:4\n",
+"    x3t=x3t+(x1(k)*sinc(%pi*(t-(k-1))));\n",
+"end\n",
+"x3t//sinc interpolated value of x(2.5)\n",
+"//(d)raised cosine interpolation method\n",
+"x4t=0;\n",
+"for k=1:4\n",
+"    p=(cos(0.5*%pi*(t-k+1))/(1-(t-k+1)^2));\n",
+"    xt=x1(k)*sinc(%pi*(t-k+1))*p;\n",
+"    x4t=x4t+xt;\n",
+"end\n",
+"x4t//raised cosine interpolated value of x(2.5)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.7: Zero_Interpolation_and_Spectrum_Replication.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Zero interpolation and spectrum replication\n",
+"XF=[0 1 2 1];\n",
+"X1F=[XF XF XF 0];\n",
+"YF=[X1F X1F];\n",
+"DF=0.5*[XF XF 0];\n",
+"GF=0.5*[XF 0 XF 0 XF 0];\n",
+"f=-0.2:0.1:1;\n",
+"f1=-0.1:0.05:1.15;\n",
+"f2=-0.4:0.2:1.2;\n",
+"f3=-0.2:0.1:1.2;\n",
+"length(f3),length(GF)\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"subplot(211);\n",
+"plot2d(f,X1F);\n",
+"ylabel('X1F');\n",
+"subplot(212);\n",
+"a.y_location='origin';\n",
+"plot2d(f1,YF);\n",
+"ylabel('YF');\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.y_location='origin';\n",
+"subplot(211);\n",
+"plot2d(f2,DF);\n",
+"ylabel('DF');\n",
+"subplot(212);\n",
+"b.y_location='origin';\n",
+"plot2d(f3,GF);\n",
+"ylabel('GF');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.8: Up_Sampling_and_Filtering.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"clf();\n",
+"X=[0 0.5 1 0.5];\n",
+"XF=[X 0];\n",
+"WF=[X X X 0];\n",
+"f=-0.5:0.25:0.5;\n",
+"f1=-0.75:0.125:0.75;\n",
+"HF=[0 1 1 1 0];\n",
+"f2=[-0.126,-0.125:0.125:0.125,0.126];\n",
+"for i=1:5\n",
+"    YF(i)=WF(i)*HF(i);\n",
+"end\n",
+"f3=[-0.126 -0.125 0 0.125 0.126];\n",
+"a=gca();\n",
+"a.y_location='origin';\n",
+"subplot(211);\n",
+"plot2d(f,XF);\n",
+"xtitle('spectrum of XF');\n",
+"a.y_location='origin';\n",
+"subplot(212);\n",
+"plot2d(f1,WF);\n",
+"xtitle('spectrum of WF');\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.y_location='origin';\n",
+"subplot(211);\n",
+"plot2d(f2,HF);\n",
+"xtitle('spectrum of HF');\n",
+"b.y_location='origin';\n",
+"subplot(212);\n",
+"plot2d(f3,YF);\n",
+"xtitle('spectrum of YF');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 7.9: Quantisation_Effects.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//(a)Quantisation effects\n",
+"sig=0.005;\n",
+"D=4;\n",
+"B=log2(D/(sig*sqrt(12)));//no.of samples\n",
+"//value of B to ensure quantisation error to 5mv\n",
+"//(b)Quantisation error and noise\n",
+"xn=0:0.2:2.0;\n",
+"xqn=[0 0 0.5 0.5 1 1 1 1.5 1.5 2 2];\n",
+"en=xn-xqn;//quantization error\n",
+"//Quantisation signal top noise ratio\n",
+"x=0;e=0;\n",
+"for i=1:length(xn)\n",
+"    x=x+xn(i)^2;\n",
+"    e=e+en(i)^2;\n",
+"end\n",
+"//method 1\n",
+"SNRQ=10*log10(x/e)\n",
+"//method 2\n",
+"SNRQ=10*log10(x/length(xn))+10.8+20*log10(4)-20*log10(2)\n",
+"SNRS=10*log10(1.33)+10*log10(12)+20*log10(4)-20*log10(2)\n",
+"//from results we see that SNRS is statistical estimate"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/8-The_Discrete_Fourier_Transform_and_its_Applications.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/8-The_Discrete_Fourier_Transform_and_its_Applications.ipynb
new file mode 100644
index 0000000..16b6cfe
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/8-The_Discrete_Fourier_Transform_and_its_Applications.ipynb
@@ -0,0 +1,925 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 8: The Discrete Fourier Transform and its Applications"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.10: DFS_of_sampled_Periodic_Signals.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DFS of sampled periodic signals\n",
+"xn=[0 ones(2:16) 0 -ones(18:32)];\n",
+"XDFS=0.032*dft(xn,-1);\n",
+"for i=1:length(XDFS)\n",
+"    if (abs(XDFS(i))<0.000001) then\n",
+"        XDFS(i)=0;\n",
+"    end\n",
+"end\n",
+"disp(XDFS,'The DFS of x[n] is');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.11: The_effects_of_leakage.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Effects of leakage\n",
+"n1=0:0.005:0.1;\n",
+"n2=0:0.005:0.125;\n",
+"n3=0:0.005:1.125;\n",
+"xt1=(2*cos(20*%pi*n1')+5*cos(100*%pi*n1'));\n",
+"xt2=(2*cos(20*%pi*n2')+5*cos(100*%pi*n2'));\n",
+"xt3=(2*cos(20*%pi*n3')+5*cos(100*%pi*n3'));\n",
+"XDFS1=abs(dft(xt1,-1))/20;\n",
+"XDFS2=abs(dft(xt2,-1))/25;\n",
+"XDFS3=abs(dft(xt3,-1))/225;\n",
+"f1=0:5:100;\n",
+"f2=0:4:100;\n",
+"f3=0:100/225:100;\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d3('gnn',f1,XDFS1);\n",
+"xlabel('analog frequency');\n",
+"ylabel('Magnitude');\n",
+"xset('window',1);\n",
+"subplot(211);\n",
+"plot2d3('gnn',f2,XDFS2);\n",
+"xlabel('analog frequency');\n",
+"ylabel('Magnitude');\n",
+"subplot(212);\n",
+"plot2d3('gnn',f3,XDFS3);\n",
+"xlabel('analog frequency');\n",
+"ylabel('Magnitude');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.15a: Methods_to_find_convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//overlapp-add and overlap-save methods of convolution\n",
+"//overlap-add method\n",
+"xn=[1 2 3 3 4 5];\n",
+"xon=[1 2 3];\n",
+"x1n=[3 4 5];\n",
+"hn=[1 1 1];\n",
+"yon=convol(xon,hn);\n",
+"y1n=convol(x1n,hn);\n",
+"yon=[yon,0,0,0];\n",
+"y1n=[0,0,0,y1n];\n",
+"yn=yon+y1n\n",
+"yn1=convol(xn,hn) "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.15b: Methods_to_find_convolution.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//(b)overlap-save method\n",
+"xn=[1 2 3 3 4 5];\n",
+"hn=[1 1 1];\n",
+"xon=[0 0 1 2 3];\n",
+"x1n=[2 3 3 4 5];\n",
+"x2n=[4 5 0 0 0];\n",
+"yon=convol(xon,hn);\n",
+"y1n=convol(x1n,hn);\n",
+"y2n=convol(x2n,hn);\n",
+"yno=yon(3:5);\n",
+"yn1=y1n(3:5);\n",
+"yn2=y2n(3:5);\n",
+"yn=[yno yn1 yn2]\n",
+"YN=convol(xn,hn)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.16: Signal_Interpolation_using_FFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//signal interpolation using FFT\n",
+"xn=[0 1 0 -1];\n",
+"XDFT=dft(xn,-1)\n",
+"ZT=[0 -2*%i 0 zeros(1:27) 0 2*%i];\n",
+"xn1=dft(ZT,1);\n",
+"t=0:1/length(xn1):1-(1/length(xn1));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(t,xn1);\n",
+"xlabel('time t');\n",
+"ylabel('Amplitude');\n",
+"xtitle('Interpolated Sinusoid:4 samples over one period');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.17: The_Concept_of_Periodogram.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//concept of periodogram\n",
+"xn=[0 1 0 -1];\n",
+"N=4;\n",
+"XDFT=dft(xn,-1);\n",
+"for i=1:length(XDFT)\n",
+"    p(i)=(1/N)*abs(XDFT(i)^2);\n",
+"end\n",
+"p//periodogram"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.18: DFT_from_matrix_formulatio.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//The DFT from the matrix formulation\n",
+"xn=[1;2;1;0];\n",
+"w=exp(-%i*%pi/2);\n",
+"for i=1:4\n",
+"    for j=1:4\n",
+"        WN(i,j)=w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"XDFT=WN*xn"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.19: Using_DFT_to_find_IDFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//using DFT to find IDFT\n",
+"XDFT=[4;-2*%i;0;2*%i];\n",
+"XDFTc=[4;2*%i;0;-2*%i];\n",
+"w=exp(-%i*%pi/2);\n",
+"for i=1:4\n",
+"    for j=1:4\n",
+"        WN(i,j)=w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"xn=1/4*(WN*XDFTc)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.1: DFT_from_Defining_Relation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DFT from defining relation\n",
+"//N-point DFT\n",
+"x=[1 2 1 0];\n",
+"XDFT=dft(x,-1);\n",
+"disp(XDFT,'The DFT of x[n] is');\n",
+"//DFT of periodic signal x with period N=4"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.20: Decimation_in_Frequency_FFT_algorithm.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//A four point decimation-in-frequency FFT algorithm\n",
+"x=[1 2 1 0];\n",
+"w=-%i;\n",
+"xdft(1)=x(1)+x(3)+x(2)+x(4);\n",
+"xdft(2)=x(1)-x(3)+w*(x(2)-x(4));\n",
+"xdft(3)=x(1)+x(3)-x(2)-x(4);\n",
+"xdft(4)=x(1)-x(3)-w*(x(2)-x(4));\n",
+"XDFT=dft(x,-1);\n",
+"xdft,XDFT"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.21: Decimation_in_time_FFT_algorithm.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//A four point decimation-in-time FFT algorithm\n",
+"x=[1 2 1 0];\n",
+"w=-%i;\n",
+"xdft=[0 0 0 0];\n",
+"for i=1:4\n",
+"    for j=1:4\n",
+"        xdft(i)=xdft(i)+x(j)*w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"XDFT=dft(x,-1);\n",
+"xdft,XDFT"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.22: 4_point_DFT_from_3_point_sequence.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//A 4-point DFT from a 3-point sequence\n",
+"xn=[1;2;1];\n",
+"w=exp(-%i*%pi/2);\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        WN(i,j)=w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"XDFT=WN*xn"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.23: 3_point_IDFT_from_4_point_DFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//A 3-point IDFT from 4-point DFT\n",
+"XDFT=[4;-2*%i;0;2*%i];\n",
+"w=exp(-%i*%pi/2);\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        WN(i,j)=w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"WI=WN';\n",
+"xn=1/4*(WI*XDFT)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.24: The_importance_of_Periodic_Extension.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//The importance of Periodic extension\n",
+"//(a)For M=3\n",
+"x=[1 2 1];\n",
+"XDFT=dft(x,-1)\n",
+"w=exp(-%i*2*%pi/3);\n",
+"for i=1:3\n",
+"    for j=1:3\n",
+"        WN(i,j)=w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"WI=WN';\n",
+"xn=1/3*WI*XDFT\n",
+"//The result is periodic with M=3 & 1 period equals x[n]\n",
+"//(b)For M=4\n",
+"y=[1 2 1 0];\n",
+"YDFT=dft(y,-1)\n",
+"w=exp(-%i*%pi/2);\n",
+"for i=1:4\n",
+"    for j=1:4\n",
+"        WN(i,j)=w^((i-1)*(j-1));\n",
+"    end\n",
+"end\n",
+"WI=WN';\n",
+"yn=1/4*WI*YDFT"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.2: The_DFT_and_conjugate_Symmetry.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//The DTFT and conjugate symmetry\n",
+"//8-point DFT\n",
+"x=[1 1 0 0 0 0 0 0];\n",
+"XDFT=dft(x,-1);\n",
+"disp(XDFT,'The DFT of x is');\n",
+"disp('from conjugate symmetry we see XDFT[k]=XDFT[8-k]');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.3: Circular_Shift_and_Flipping.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Circular shift and flipping\n",
+"//(a)right circular shift\n",
+"y=[1 2 3 4 5 0 0 6];\n",
+"f=y;g=y;h=y;\n",
+"for i=1:2\n",
+"    b=f(length(f));\n",
+"    for j=length(f):-1:2\n",
+"        f(j)=f(j-1);\n",
+"     end\n",
+"     f(1)=b;\n",
+"end\n",
+"disp(f,'By right circular shift y[n-2] is');\n",
+"//(b)left circular shift\n",
+"for i=1:2\n",
+"    a=g(1);\n",
+"    for j=1:length(g)-1\n",
+"        g(j)=g(j+1);\n",
+"     end\n",
+"     g(length(g))=a;\n",
+"end\n",
+"disp(g,'By left circular shift y[n+2] is');\n",
+"//(c)flipping property\n",
+"h=[h(1) h(length(h):-1:2)];\n",
+"disp(h,'By flipping property y[-n] is');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.4: Properties_of_DFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"x=[1 2 1 0];\n",
+"XDFT=dft(x,-1)\n",
+"//(a)time shift property\n",
+"y=x;\n",
+"for i=1:2\n",
+"    a=y(1);\n",
+"    for j=1:length(y)-1\n",
+"        y(j)=y(j+1);\n",
+"     end\n",
+"     y(length(y))=a;\n",
+"end\n",
+"YDFT=dft(y,-1)\n",
+"disp(YDFT,'By Time-Shift property DFT of x[n-2] is');  \n",
+"//(b)flipping property\n",
+"g=[x(1) x(length(x):-1:2)]\n",
+"GDFT=dft(g,-1)\n",
+"disp(GDFT,'By Time reversal property DFT of x[-n] is');  \n",
+"//(c)conjugation property\n",
+"p=XDFT;\n",
+"PDFT=[p(1);p(4:-1:2)];\n",
+"disp(YDFT,'BY conjugation property DFT of x*[n] is');  "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.5a: Properties_of_DFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//properties of DFT\n",
+"//a1)product\n",
+"xn=[1 2 1 0];\n",
+"XDFT=dft(xn,-1)\n",
+"hn=xn.*xn\n",
+"HDFT=dft(hn,-1)\n",
+"HDFT1=1/4*(convol(XDFT,XDFT))\n",
+"HDFT1=[HDFT1,zeros(8:12)];\n",
+"HDFT2=[HDFT1(1:4);HDFT1(5:8);HDFT1(9:12)];\n",
+"HDFT3=[0 0 0 0];\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        HDFT3(i)=HDFT3(i)+HDFT2(j,i);\n",
+"    end\n",
+"end\n",
+"disp(HDFT3,'DFT of x[n]^2 is');\n",
+"//a2)periodic convolution\n",
+"vn=convol(xn,xn);\n",
+"vn=[vn,zeros(8:12)];\n",
+"vn=[vn(1:4);vn(5:8);vn(9:12)];\n",
+"vn1=[0 0 0 0];\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        vn1(i)=vn1(i)+vn(j,i);\n",
+"    end\n",
+"end\n",
+"VDFT=dft(vn1,-1);\n",
+"VDFT1=XDFT.*XDFT;\n",
+"disp(VDFT1,'DFT of x[n]*x[n] is');\n",
+"//a3)signal energy(parcewell's theorem)\n",
+"xn2=xn^2;\n",
+"E=0;\n",
+"for i=1:length(xn2)\n",
+"    E=E+abs(xn2(i));\n",
+"end\n",
+"XDFT2=XDFT^2\n",
+"E1=0;\n",
+"for i=1:length(XDFT2)\n",
+"    E1=E1+abs(XDFT2(i));\n",
+"end\n",
+"E,(1/4)*E1;\n",
+"disp(1/4*E1,'The energy of the signal is');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.5b: Properties_of_DFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//b1)modulation\n",
+"XDFT=[4 -2*%i 0 2*%i];\n",
+"xn=dft(XDFT,1)\n",
+"for i=1:length(xn)\n",
+"    zn(i)=xn(i)*%e^((%i*%pi*(i-1))/2);\n",
+"end\n",
+"disp(zn,'The IDFT of XDFT[k-1] is');\n",
+"ZDFT=[2*%i 4 -2*%i 0];\n",
+"zn1=dft(ZDFT,1)\n",
+"//b2)periodic convolution\n",
+"HDFT=(convol(XDFT,XDFT))\n",
+"HDFT=[HDFT,zeros(8:12)];\n",
+"HDFT=[HDFT(1:4);HDFT(5:8);HDFT(9:12)];\n",
+"HDFT1=[0 0 0 0];\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        HDFT1(i)=HDFT1(i)+HDFT(j,i);\n",
+"    end\n",
+"end\n",
+"HDFT1;\n",
+"hn=dft(HDFT1,1)\n",
+"hn1=4*(xn.*xn);\n",
+"disp(hn1,'The IDFT of XDFT*XDFT is');\n",
+"//b3)product\n",
+"WDFT=XDFT.*XDFT;\n",
+"wn=dft(WDFT,1)\n",
+"wn1=convol(xn,xn);\n",
+"wn1=[wn1,zeros(8:12)];\n",
+"wn1=[wn1(1:4);wn1(5:8);wn1(9:12)];\n",
+"WN=[0 0 0 0];\n",
+"for i=1:4\n",
+"    for j=1:3\n",
+"        WN(i)=WN(i)+wn1(j,i);\n",
+"    end\n",
+"end\n",
+"disp(WN,'The IDFT of XDFT.XDFT is');\n",
+"//b4)Central ordinates and signal Energy\n",
+"E=0;\n",
+"for i=1:length(xn)\n",
+"    E=E+abs(xn(i)^2);\n",
+"end\n",
+"disp(E,'the signal energy is'); "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.5c: Properties_of_DFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Regular convolution\n",
+"xn=[1 2 1 0];\n",
+"yn=[1 2 1 0 0 0 0];\n",
+"YDFT=dft(yn,-1)\n",
+"SDFT=YDFT.*YDFT\n",
+"sn=dft(SDFT,1)\n",
+"sn1=convol(xn,xn)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.6: Signal_and_Spectrum_Replication.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Signal and spectrum replication\n",
+"xn=[2 3 2 1];\n",
+"XDFT=dft(xn,-1)\n",
+"yn=[xn xn xn];\n",
+"YDFT=dft(yn,-1)\n",
+"YDFT1=3*[XDFT(1:1/3:length(XDFT))];\n",
+"for i=2:3\n",
+"    YDFT1(i:3:length(YDFT1))=0;\n",
+"end\n",
+"YDFT1(12:-1:11)=0;\n",
+"disp(YDFT1,'the DFT of x[n/3] is');\n",
+"hn=[xn(1:1/3:length(xn))]\n",
+"for i=2:3\n",
+"    hn(i:3:length(hn))=0;\n",
+"end\n",
+"hn(12:-1:11)=0;\n",
+"hn\n",
+"HDFT=dft(hn,-1)\n",
+"HDFT1=[XDFT;XDFT;XDFT];\n",
+"disp(HDFT1,'the DFT of y[n]=[x[n],x[n],x[n]] is');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.7: Relating_DFT_and_DTFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//relating DFT and IDFT\n",
+"XDFT1=[4 -2*%i 0 2*%i];\n",
+"xn1=dft(XDFT1,1);\n",
+"disp(xn1,'The IDFT of XDFT1');\n",
+"XDFT2=[12 -24*%i 0 4*%e^(%i*%pi/4) 0 4*%e^(-%i*%pi/4) 0 24*%i];\n",
+"xn2=dft(XDFT2,1);\n",
+"disp(xn2,'The IDFT of XDFT1'); "
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.8: Relating_DFT_and_DTFT.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Relating DFT and DTFT\n",
+"xn=[1 2 1 0];\n",
+"XDFT=dft(xn,-1);\n",
+"//for F=k/4,k=0,1,2,3\n",
+"for k=1:4\n",
+"    XF(k)=1+2*%e^(-%i*%pi*(k-1)/2)+%e^(-%i*%pi*(k-1));\n",
+"end\n",
+"XF,XDFT\n",
+"disp(XF,'The DFT of x[n] is');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.9a: The_DFT_and_DFS_of_sinusoids.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DFT and DFS of sinusoids\n",
+"n2=0:0.5/1000:5.5/100;\n",
+"xt=4*cos(100*%pi*n2');\n",
+"n=0:(0.5)/100:(5.5)/100;//F=3/12 hence N=12\n",
+"xn=4*cos(100*%pi*n');\n",
+"XDFT=dft(xn,-1);\n",
+"n1=0:11;\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(n2,xt);\n",
+"plot2d3('gnn',n,xn);\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.x_location='origin';\n",
+"plot2d3('gnn',n1,XDFT);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.9b: The_DFT_and_DFS_of_sinusoids.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DFT and DFS of sinusoids\n",
+"n2=0:1/1280:31/128;\n",
+"xt=4*sin(72*%pi*n2');\n",
+"n=0:1/128:31/128;//F=9/32 hence N=32\n",
+"xn=4*sin(72*%pi*n');\n",
+"XDFT=abs(dft(xn,-1));\n",
+"n1=0:31;\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(n2,xt);\n",
+"plot2d3('gnn',n,xn);\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.x_location='origin';\n",
+"plot2d3('gnn',n1,XDFT);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.9c: The_DFT_and_DFS_of_sinusoids.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DFT and DFS of sinusoids\n",
+"n2=0:1/840:6/21;\n",
+"xt=4*sin(72*%pi*n2')-6*cos(12*%pi*n2');\n",
+"n=0:1/21:6/21;//F=3/12 hence N=12\n",
+"xn=4*sin(72*%pi*n')-6*cos(12*%pi*n');\n",
+"XDFT=abs(dft(xn,-1));\n",
+"n1=0:6;\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(n2,xt);\n",
+"plot2d3('gnn',n,xn);\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.x_location='origin';\n",
+"plot2d3('gnn',n1,XDFT);"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 8.9d: The_DFT_and_DFS_of_sinusoids.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DFT and DFS of sinusoids\n",
+"n2=0:1/2400:23/240;\n",
+"xt=1+4*sin(120*%pi*n2')+4*sin(40*%pi*n2');\n",
+"n=0:1/240:23/240;//F=9/32 hence N=32\n",
+"xn=1+4*sin(120*%pi*n')+4*sin(40*%pi*n');\n",
+"XDFT=abs(dft(xn,-1));\n",
+"n1=0:23;\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(n2,xt);\n",
+"plot2d3('gnn',n,xn);\n",
+"xset('window',1);\n",
+"b=gca();\n",
+"b.x_location='origin';\n",
+"plot2d3('gnn',n1,XDFT);"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}
diff --git a/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/9-Design_of_IIR_Filters.ipynb b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/9-Design_of_IIR_Filters.ipynb
new file mode 100644
index 0000000..cd4b61e
--- /dev/null
+++ b/Digital_Signal_Processing_A_Modern_Introduction_by_A_Ashok/9-Design_of_IIR_Filters.ipynb
@@ -0,0 +1,677 @@
+{
+"cells": [
+ {
+		   "cell_type": "markdown",
+	   "metadata": {},
+	   "source": [
+       "# Chapter 9: Design of IIR Filters"
+	   ]
+	},
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.10a: Bilinear_Design_of_Second_Order_Filters.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Bilinear design of second order filters\n",
+"s=%s;z=%z;\n",
+"fo=6;Wo=2*%pi*fo/25;\n",
+"delf=5;S=25;\n",
+"B=cos(2*%pi*fo/25)\n",
+"C=tan(%pi*delf/25)\n",
+"HS=1/(s+1);\n",
+"HZ=horner(HS,(z^2-(2*B*z)+1)/(C*(z^2)-C))\n",
+"f=0:0.5:12.5;\n",
+"HZ1=horner(HZ,exp(%i*2*%pi*f'/25));\n",
+"HZ1=abs(HZ1);\n",
+"W2=(%pi*delf/25)+acos(cos(Wo)*cos(%pi*delf/25))\n",
+"W1=W2-(2*%pi*delf/25)\n",
+"f1=S*W1/(2*%pi),f2=S*W2/(2*%pi)\n",
+"f3=[f1;fo;f2];\n",
+"HZf=abs(horner(HZ,exp(%i*2*%pi*f3'/25)));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(f,HZ1,rect=[0 0 13 1]);\n",
+"plot2d3('gnn',f3,HZf);\n",
+"xlabel('Analog Frequency f[kHZ]');\n",
+"ylabel('Magnitude');\n",
+"xtitle('Band pass filter fo=6kHZ,delf=5kHZ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.10b: Bilinear_Design_of_Second_Order_Filters.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Bilinear design of second order filters\n",
+"s=%s;z=%z;\n",
+"f1=4;f2=9;\n",
+"delf=f2-f1;S=25;\n",
+"B=cos(%pi*(f1+f2)/25)/cos(%pi*(f2-f1)/25)\n",
+"C=tan(%pi*delf/25)\n",
+"HS=1/(s+1);\n",
+"HZ=horner(HS,(z^2-(2*B*z)+1)/(C*(z^2)-C))\n",
+"f=0:0.5:12.5;\n",
+"HZ1=horner(HZ,exp(%i*2*%pi*f'/25));\n",
+"HZ1=abs(HZ1);\n",
+"fo=S*acos(B)/(2*%pi)\n",
+"f3=[f1 fo f2]; \n",
+"HZf=abs(horner(HZ,exp(-%i*2*%pi*f3'/25)));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(f,HZ1);\n",
+"plot2d3('gnn',f3,HZf);\n",
+"xlabel('Analog Frequency f[kHZ]');\n",
+"ylabel('Magnitude');\n",
+"xtitle('Band pass filter f1=4kHZ,f2=9kHZ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.10c: Bilinear_Design_of_Second_Order_Filters.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Bilinear design of second order filters\n",
+"s=%s;z=%z;\n",
+"fo=40;Wo=2*%pi*fo/200;\n",
+"delf=2;S=25;\n",
+"delW=2*%pi*delf/200;\n",
+"B=cos(2*%pi*fo/200)\n",
+"K=0.557;\n",
+"C=K*tan(0.5*delW)\n",
+"HS=1/(s+1);\n",
+"HZ=horner(HS,(z^2-(2*B*z)+1)/(C*(z^2)-C))\n",
+"f=0:2:100;\n",
+"f1=35:0.5:45;\n",
+"HZ1=horner(HZ,exp(%i*2*%pi*f'/200));\n",
+"HZ2=horner(HZ,exp(%i*2*%pi*f1'/200));\n",
+"HZ1=abs(HZ1);\n",
+"HZ2=abs(HZ2);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"subplot(211);\n",
+"plot2d(f,HZ1);\n",
+"xlabel('Analog Frequency f[kHZ]');\n",
+"ylabel('Magnitude');\n",
+"xtitle('peaking filter fo=40HZ,delf=2HZ');\n",
+"subplot(212);\n",
+"plot2d(f1,HZ2);\n",
+"xtitle('Blowup of response 35HZ to 45HZ');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.11: Interference_Rejection.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//interference Rejection\n",
+"//design oh high-Q and low-Q notch filters\n",
+"s=%s;z=%z;\n",
+"Q=50;\n",
+"fo=60;S=300;\n",
+"delf=fo/Q;\n",
+"Wo=2*%pi*fo/S;\n",
+"delW=2*%pi*delf/S;\n",
+"C=tan(0.5*delW),B=cos(Wo)\n",
+"HS=(s)/(s+1);\n",
+"H1Z=horner(HS,(z^2-(2*B*z)+1)/(C*(z^2)-C))\n",
+"Q1=5;delf1=fo/Q1;\n",
+"delW1=2*%pi*delf1/S;\n",
+"C1=tan(0.5*delW1),B1=cos(Wo)\n",
+"H2Z=horner(HS,(z^2-(2*B1*z)+1)/(C1*(z^2)-C1))\n",
+"f=0:0.5:150;\n",
+"H1Z1=horner(H1Z,exp(%i*2*%pi*f'/S));\n",
+"H2Z1=horner(H2Z,exp(%i*2*%pi*f'/S));\n",
+"a=gca();\n",
+"subplot(211);\n",
+"plot2d(f,H1Z1);\n",
+"xlabel('Analog Frequency f[Hz]');\n",
+"ylabel('Magnitude');\n",
+"xtitle('60 HZ notch filter with Q=50');\n",
+"subplot(212);\n",
+"plot2d(f,H2Z1);\n",
+"xlabel('Analog Frequency f[Hz]');\n",
+"ylabel('Magnitude');\n",
+"xtitle('60 HZ notch filter with Q=5');\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.12: IIR_Filter_Desig.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//IIR filter design\n",
+"//Design of chebyshev IIR filter with following specifications\n",
+"fp1=1.6;fp2=1.8;fs1=3.2;fs2=4.8;//pass band edges\n",
+"Ap=2;As=20;S=12;\n",
+"s=%s;z=%z;\n",
+"//(a)Indirect Bilinear design\n",
+"W=2*%pi*[fp1 fp2 fs1 fs2]/S\n",
+"C=2;\n",
+"omega=2*tan(0.5*W');//prewarping each band edge frequency\n",
+"epsilon=sqrt(10^(0.1*Ap)-1);\n",
+"n=acosh(((10^(0.1*As)-1)/epsilon^2)^1/2)/(acosh(fs1/fp1));\n",
+"n=ceil(n)\n",
+"alpha=(1/n)*asinh(1/epsilon);\n",
+"for i=1:n\n",
+"    B(i)=(2*i-1)*%pi/(2*n);\n",
+"end\n",
+"for i=1:n\n",
+"    p(i)=-sinh(alpha)*sin(B(i))+%i*cosh(alpha)*cos(B(i));\n",
+"end\n",
+"Qs=1;\n",
+"for i=1:n\n",
+"    Qs=Qs*(s-p(i))\n",
+"end\n",
+"Qo=0.1634;\n",
+"HPS=Qo/Qs\n",
+"HBPS=horner(HPS,(s^2+1.5045^2)/(s*1.202))\n",
+"HZ=horner(HBPS,2*(z-1)/(z+1))\n",
+"f=0:0.001:0.5;\n",
+"HZF=abs(horner(HZ,exp(%i*2*%pi*f')));\n",
+"HBPF=abs(horner(HBPS,%i*2*%pi*f'));\n",
+"a=gca();\n",
+"plot2d(f,HZF);\n",
+"plot2d(f,HBPF);\n",
+"xlabel('Analog Frequency');\n",
+"ylabel('magnitude');\n",
+"xtitle('band pass filter designed by the bilinear transformation');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.1: Response_Invariant_Mappings.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Response in variant mappings\n",
+"s=%s;z=%z;\n",
+"HS=1/(s+1);\n",
+"f=0:0.05:0.5;\n",
+"HS1=horner(HS,(%i*%pi*2*f'));\n",
+"ts=1;\n",
+"HZ=z/(z-0.3679);\n",
+"HZ1=horner(HZ,exp(%i*%pi*2*f'));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"subplot(211)\n",
+"plot2d(f,HS1);\n",
+"plot2d(f,HZ1);\n",
+"xlabel('Analog frequency f(Hz)');\n",
+"ylabel('Magnitude');\n",
+"xtitle('magnitude of H(s) and H(z)');\n",
+"HZ1=HZ1-0.582;//magnitude after gain matching at dc \n",
+"b=gca();\n",
+"b.x_location='origin';\n",
+"subplot(212);\n",
+"plot2d(f,HS1);\n",
+"plot2d(f,HZ1);\n",
+"xlabel('Analog frequency f(Hz)');\n",
+"ylabel('Magnitude');\n",
+"xtitle('magnitude after gain matching at DC');\n",
+"//Impulse response of analog and digital filter\n",
+"t=0:0.01:6;\n",
+"ht=exp(-t');\n",
+"n=0:6;\n",
+"hn=exp(-n');\n",
+"xset('window',1)\n",
+"c=gca();\n",
+"subplot(211);\n",
+"plot2d(t,ht);\n",
+"plot2d3('gnn',n,hn);\n",
+"xlabel('DT index n and time t=nts');\n",
+"ylabel('Amplitude');\n",
+"xtitle('Impulse response of analog and digital filter');\n",
+"//Step response of analog and digital filter\n",
+"t=0:0.01:6;\n",
+"st=1-exp(-t');\n",
+"n=0:6;\n",
+"sn=(%e-%e^(-n'))/(%e-1);\n",
+"c=gca();\n",
+"subplot(212);\n",
+"plot2d(t,st);\n",
+"plot2d3('gnn',n,sn);\n",
+"xlabel('DT index n and time t=nts');\n",
+"ylabel('Amplitude');\n",
+"xtitle('Step response of analog and digital filter');\n",
+"\n",
+"\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.2: Impulse_Invariant_Mappings.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Impulse invariant mappings\n",
+"//(a)converting H(s)=4s+7/s^2+5s+4 to H(z) using impulse invariance\n",
+"s=%s;\n",
+"z=%z;\n",
+"HS=(4*s+7)/(s^2+5*s+4);\n",
+"pfss(HS)\n",
+"ts=0.5;\n",
+"HZ=3*z/(z-%e^(-4*ts))+z/(z-%e^(-ts))\n",
+"//(b)converting H(s)=4s+7/s^2+5s+4 to H(z) using impulse invariance\n",
+"HS1=4/((s+1)*(s^2+4*s+5))\n",
+"pfss(HS1);\n",
+"HZ1=2*z/(z-%e^-ts)+(2*1.414*z^2*cos(-0.75*%pi)-2*1.414*(z/%e)*cos(0.5-0.75*%pi))/(z^2-2*(z/%e)*cos(0.5)+%e^-2)"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.3ab: Modified_Impulse_Invariant_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//(a)Impulse invariant design\n",
+"s=%s;z=%z;\n",
+"HS=1/(s+1);\n",
+"H1s=horner(HS,3*s/%pi)\n",
+"H1z=%pi/3*z/(z-%e^(-%pi/3))\n",
+"//Modified inmpulse invariant design\n",
+"HZ=z/(z-1/%e);\n",
+"HMZ=0.5*(z+1/%e)/(z-1/%e);//modified transfer function\n",
+"H1Z=HZ/horner(HZ,1)\n",
+"HM1Z=HMZ/horner(HMZ,1)\n",
+"f=0:0.05:0.5;\n",
+"HZ1=horner(HZ,exp(%i*2*%pi*f'));\n",
+"HMZ1=horner(HMZ,exp(%i*2*%pi*f'));\n",
+"H1Z1=horner(H1Z,exp(%i*2*%pi*f'));\n",
+"HM1Z1=horner(HM1Z,exp(%i*2*%pi*f'));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(f,HZ1);\n",
+"plot2d(f,HMZ1);\n",
+"plot2d(f,H1Z1);\n",
+"plot2d(f,HM1Z1);\n",
+"xlabel('digital frequency');\n",
+"ylabel('Magnitude');\n",
+"xtitle('Impulse invariant design of H(s)=1/s+1 (dashed)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.3cd: Modified_Impulse_Invariant_Design.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//modified Impulse invariant Design\n",
+"//(c)H(s)=4s+7/s^2+5s+4\n",
+"s=%s;z=%z;\n",
+"HS=(4*s+7)/(s^2+5*s+4);\n",
+"[d1]=degree(numer(HS));\n",
+"[d2]=degree(denom(HS));\n",
+"HZ=((3*z)/(z-%e^-2))+(z/(z-%e^-0.5))\n",
+"if (d2-d1==1) then\n",
+"    h=(4+7/%inf)/(1+5/%inf+4/%inf)\n",
+"    HMZ=HZ-0.5*h\n",
+"else\n",
+"    HMZ=HZ\n",
+"end\n",
+"HS1=4/((s+1)*(s^2+4*s+5))\n",
+"HZ1=(0.2146*z^2+0.093*z)/(z^3-1.2522*z^2+0.527*z-0.0821);\n",
+"[d1]=degree(numer(HS1));\n",
+"[d2]=degree(denom(HS1));\n",
+"if (d2-d1==1) then\n",
+"    HMZ1=HZ1-0.5*h\n",
+"else\n",
+"    HMZ1=HZ1\n",
+"end"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.5: Mappings_from_Difference_Algorithms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Mappings from difference algorithms\n",
+"//Backward difference mappings\n",
+"s=%s;z=%z;\n",
+"ts=1;a=1;\n",
+"HS=1/(s+a);\n",
+"HZa=horner(HS,(z-1)/(z*ts))\n",
+"z1=roots(denom(HZa))//for ts >0 HZa always stable\n",
+"HZb=horner(HS,(z-1)/ts)\n",
+"z2=roots(denom(HZb))//stable only for 0<ats<2\n",
+"HZc=horner(HS,(z^2-1)/(2*z*ts))\n",
+"z3=roots(denom(HZc))//magnitude of 1 pole is always>1 hence unstable\n",
+""
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.6: Mappings_From_Integration_Algorithms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Mappings from integration algorithm\n",
+"//(a)Trapezoidal integration algorithm\n",
+"s=%s;z=%z;\n",
+"a=input('enter the value of a')\n",
+"ts=input('enter the value of sampling time')\n",
+"HS=1/(s+1);\n",
+"HZa=horner(HS,2*(z-1)/(ts*(z+1)))\n",
+"za=roots(denom(HZa))//pole always less than 1 ,hence HZ is stable\n",
+"//(b)simphson's algorithm\n",
+"HZb=horner(HS,3*(z^2-1)/(ts*(z^2+4*z+1)))\n",
+"zb=roots(denom(HZb))\n",
+"//magnitude of 1 pole always greater than 1 ,hence HZ is unstable"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.7: DTFT_of_Numerical_Algorithms.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//DTFT of numerical algorithms\n",
+"//(a)For trapezoidal numerical integrator\n",
+"ieee(2)\n",
+"F=0:0.01:0.2;\n",
+"HTF=1/(%i*2*tan(%pi*F'));\n",
+"HIF=1/(%i*2*%pi*F');\n",
+"Ha=1-((%pi*F')^2)/3-((%pi*F')^4/45);\n",
+"//(b)For simphson's numerical integrator\n",
+"Hb=((2*%pi*F')).*((2+cos(2*%pi*F'))./(3*sin(2*%pi*F')));\n",
+"//For forward difference operator\n",
+"HFF=(%e^(%i*2*%pi*F'))-1;\n",
+"HDF=1/(%i*2*%pi*F');\n",
+"Hc=1+(%i*2*%pi*F')/2-(2*%pi*F')^2/6;\n",
+"Hc=abs(Hc);\n",
+"//for central difference operator\n",
+"HCF=sin(2*%pi*F')./(%i*4*%pi*%pi*F'^2);\n",
+"Hd=abs(sin(2*%pi*F')./(2*%pi*F'));\n",
+"length(F),length(Ha)\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(F,Ha,rect=[0,0.8,0.2,1.1]);\n",
+"plot2d(F,Hb);\n",
+"xtitle('Magnitude spectrum of Integration algorithms','Digital Frequency F','Magnitude');\n",
+"xset('window',1);\n",
+"plot2d(F,Hc,rect=[0,0.8,0.2,1.1]);\n",
+"plot2d(F,Hd);\n",
+"xtitle('Magnitude spectrum of difference algorithms','Digital Frequency F','Magnitude');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.8a: Bilinear_Transformation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Bilinear transformation\n",
+"//To convert bessel analog filter to digital filter\n",
+"s=%s;\n",
+"z=%z;\n",
+"HS=3/(s^2+3*s+3);\n",
+"Wa=4;//analog omega\n",
+"Wd=%pi/2;//digital omega\n",
+"T=(2/Wa)*(tan(Wd/2));\n",
+"HZ=horner(HS,(2/T)*(z-1)/(z+1))\n",
+"f=0:0.1:6;\n",
+"HS1=horner(HS,(%i*4*f'/3));\n",
+"HS1=abs(HS1);\n",
+"HZ1=horner(HZ,exp(-%i*%pi*f'/6));\n",
+"HZ1=abs(HZ1);\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(f,HS1);\n",
+"plot2d(f,HZ1);\n",
+"xlabel('Analog Frequency f[kHZ)');\n",
+"ylabel('Magnitude');\n",
+"xtitle('Bessel filter H(s) and digital filter H(z)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.8b: Bilinear_Transformation.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//Bilinear transformation\n",
+"//To convert twin-T notch analog filter to digital filter\n",
+"s=%s;\n",
+"z=%z;\n",
+"HS=(s^2+1)/(s^2+4*s+1);\n",
+"Wo=1;\n",
+"S=240;f=60;//sampling and analog frequencies\n",
+"W=0.5*%pi;//digital frequency\n",
+"C=Wo/tan(0.5*W)\n",
+"HZ=horner(HS,C*(z-1)/(z+1))\n",
+"f=0:120;\n",
+"HZ1=abs(horner(HZ,exp(-%i*%pi*f'/120)));\n",
+"HS1=abs(horner(HS,(%i*f'/60)));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(f,HZ1);\n",
+"plot2d(f,HS1);\n",
+"xlabel('Analog Frequency f[kHZ]');\n",
+"ylabel('Magnitude');\n",
+"xtitle('Notch filter H(S) and digital filter H(z)');"
+   ]
+   }
+,
+{
+		   "cell_type": "markdown",
+		   "metadata": {},
+		   "source": [
+			"## Example 9.9: D2D_transformations.sce"
+		   ]
+		  },
+  {
+"cell_type": "code",
+	   "execution_count": null,
+	   "metadata": {
+	    "collapsed": true
+	   },
+	   "outputs": [],
+"source": [
+"//D2D transformations\n",
+"//(a)LP 2 HP transformation\n",
+"z=%z;\n",
+"HZ=(3*(z+1)^2)/(31*z^2-26*z+7);\n",
+"WD=0.5*%pi;WC=0.25*%pi;//Band edges\n",
+"a=-cos(0.5*(WD+WC))/cos(0.5*(WD-WC))//Mapping parameter\n",
+"HHPZ=horner(HZ,-(z+a)/(1+a*z))\n",
+"//(b)LP 2 BP transformation\n",
+"W1=0.25*%pi;\n",
+"W2=0.75*%pi;\n",
+"K=tan(0.5*WD)/tan(0.5*(W2-W1))\n",
+"a=-cos(0.5*(W1+W2))/cos(0.5*(W1-W2))//Mapping parameters k,a,A1,A2\n",
+"A1=2*K*a/(K+1),A2=(K-1)/(K+1)\n",
+"HBPZ=horner(HZ,-(z^2+A1*z+A2)/(A2*z^2+A1*z+1))\n",
+"//(c)Lp 2 BS transformation\n",
+"w1=3/8*%pi;w2=5/8*%pi;//band edges\n",
+"K1=tan(0.5*WD)*tan(0.5*(w2-w1))\n",
+"a1=-cos(0.5*(w1+w2))/cos(0.5*(w2-w1))//Mapping parameters k1,a1,A1c,A2c\n",
+"A1c=2*a1/(K1+1),A2c=-(K1-1)/(K1+1)\n",
+"HBSZ=horner(HZ,(z^2+A1c*z+A2c)/(A2c*z^2+A1c*z+1))\n",
+"f=0:1/256:4;\n",
+"for i=1:length(f)\n",
+"HZ1(i)=horner(HZ,exp(-%i*%pi*f(i)/4));\n",
+"end\n",
+"HZ1=abs(HZ1);\n",
+"HHPZ1=abs(horner(HHPZ,exp(-%i*%pi*f'/4)));\n",
+"HBPZ1=abs(horner(HBPZ,exp(-%i*%pi*f'/4)));\n",
+"HBSZ1=abs(horner(HBSZ,exp(-%i*%pi*f'/4)));\n",
+"a=gca();\n",
+"a.x_location='origin';\n",
+"plot2d(f,HZ1);\n",
+"plot2d(f,HHPZ1);\n",
+"plot2d(f,HBPZ1);\n",
+"plot2d(f,HBSZ1);\n",
+"xlabel('Analog Frequency');\n",
+"ylabel('Magnitude');\n",
+"xtitle('Digital-to-digital transformations of a low pass filter');"
+   ]
+   }
+],
+"metadata": {
+		  "kernelspec": {
+		   "display_name": "Scilab",
+		   "language": "scilab",
+		   "name": "scilab"
+		  },
+		  "language_info": {
+		   "file_extension": ".sce",
+		   "help_links": [
+			{
+			 "text": "MetaKernel Magics",
+			 "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+			}
+		   ],
+		   "mimetype": "text/x-octave",
+		   "name": "scilab",
+		   "version": "0.7.1"
+		  }
+		 },
+		 "nbformat": 4,
+		 "nbformat_minor": 0
+}