initial commit / add all books

35 files changed, 506 insertions, 0 deletions

diff --git a/3812/CH1/EX1.14.a/1_14_a.sce b/3812/CH1/EX1.14.a/1_14_a.sce
new file mode 100644
index 000000000..1cde65ccd
--- /dev/null
+++ b/3812/CH1/EX1.14.a/1_14_a.sce
@@ -0,0 +1,8 @@
+//Example 1.14<a>

+//check the given signL is PERIODIC OR NOT//

+clc ;

+t=-10:.01:10;

+x=%i*(exp(%i*10*t));

+subplot (311)

+plot (t,x);

+disp ('(a) this shows that the given signal is periodic with period (.2*%pi)');

diff --git a/3812/CH1/EX1.14.b/1_14_b.sce b/3812/CH1/EX1.14.b/1_14_b.sce
new file mode 100644
index 000000000..5ce4cffe1
--- /dev/null
+++ b/3812/CH1/EX1.14.b/1_14_b.sce
@@ -0,0 +1,8 @@
+//Example 1.14<b>

+//check the given signL is PERIODIC OR NOT e^(-1+j)*t

+clc ;

+t=-1:.01:1;

+x=(exp(-1+%i)*t);

+f=1/2*%pi;

+N=1/f;

+disp (N,'this shows that the given signal is not periodic');

diff --git a/3812/CH1/EX1.14.c/1_14_c.sce b/3812/CH1/EX1.14.c/1_14_c.sce
new file mode 100644
index 000000000..d25dcad50
--- /dev/null
+++ b/3812/CH1/EX1.14.c/1_14_c.sce
@@ -0,0 +1,8 @@
+//Example 1.14<c>

+// Find wheather the following signal is periodic or not x3(n)=e^(i*7*pi*n)

+clc;

+n=-21:21;

+x=exp(%i *7* %pi *n);

+f=(7*%pi)/(2*%pi);

+N=1/f;

+disp(N,'the given signal is periodic');

diff --git a/3812/CH1/EX1.15.a/1_15_a.sce b/3812/CH1/EX1.15.a/1_15_a.sce
new file mode 100644
index 000000000..c5c7892ba
--- /dev/null
+++ b/3812/CH1/EX1.15.a/1_15_a.sce
@@ -0,0 +1,8 @@
+//Example 1.15<a>

+// Find wheather the following signal is periodic or not x3(n)=2*e^(%i*(t+%pi/4))

+clc;

+t=-21:21;

+x=2*exp(%i*(t+%pi/4));

+f=1/(2*%pi);

+N=1/f;

+disp('samples',N,'(b)the given signal is not periodic');

diff --git a/3812/CH1/EX1.18.c/1_18_c.sce b/3812/CH1/EX1.18.c/1_18_c.sce
new file mode 100644
index 000000000..f56349128
--- /dev/null
+++ b/3812/CH1/EX1.18.c/1_18_c.sce
@@ -0,0 +1,11 @@
+// example 1.18<c>

+//determine the values of power and energy

+clc ;

+t =0:0.01:100;

+A=1;

+x=A*cos (t);

+P=(integrate('(A*cos(t))^2','t',0,2*%pi ))/(2*%pi);

+disp(P,'The power of the signal is:');

+E=(integrate('(A*cos(t))^2','t',0,2*%pi));

+disp(E,'The energy is:');

+disp('As t tends to infinity energy also tends to infinity but power remains finite hence it is power signal');

diff --git a/3812/CH1/EX1.18.d/1_18_d.sce b/3812/CH1/EX1.18.d/1_18_d.sce
new file mode 100644
index 000000000..693d03f07
--- /dev/null
+++ b/3812/CH1/EX1.18.d/1_18_d.sce
@@ -0,0 +1,12 @@
+//Example 1.18<d>

+//determine the values of power and energy 

+clc ;

+E=0;

+for n=0:200

+x(n+1)=(1/2)^n;

+end

+for n=0:200

+E=E+x(n +1)^2;

+end

+disp(E,'The energy of the signal is; ' );

+disp ('since the energy is finite, hence it is energy signal');

diff --git a/3812/CH1/EX1.19.a/1_19_a.sce b/3812/CH1/EX1.19.a/1_19_a.sce
new file mode 100644
index 000000000..967a0c326
--- /dev/null
+++ b/3812/CH1/EX1.19.a/1_19_a.sce
@@ -0,0 +1,11 @@
+// example 1.19<a>

+//determine whether the following signals are power or energy signal

+clc ;

+t =0:0.01:100;

+A=1;

+x=A*sin(t);

+P=(integrate('(A*sin(t))^2','t',-%pi,%pi))/(2*%pi);

+disp(P,'The power of the signal is:');

+E=(integrate('(A*sin(t))^2','t',-%pi,%pi));

+disp(E,'The energy is:');

+disp('As t tends to infinity energy also tends to infinity but power remains finite hence it is power signal');

diff --git a/3812/CH1/EX1.19.b/1_19_d.sce b/3812/CH1/EX1.19.b/1_19_d.sce
new file mode 100644
index 000000000..0e693e692
--- /dev/null
+++ b/3812/CH1/EX1.19.b/1_19_d.sce
@@ -0,0 +1,10 @@
+//example 1.19<d>

+//determine whether the following signals are power or energy signal

+clc ;

+t=0:0.01:100;

+x=1;

+P=(integrate('1^2','t',0,1))/2;

+disp(P,'The power of the signal is:');

+E=(integrate('1^2','t',0,1));

+disp(E,'The energy is:');

+disp('As t tends to infinity energy also tends to infinity but power remains finite hence it is power signal');

diff --git a/3812/CH1/EX1.19.e/1_19_e.sce b/3812/CH1/EX1.19.e/1_19_e.sce
new file mode 100644
index 000000000..18d66be01
--- /dev/null
+++ b/3812/CH1/EX1.19.e/1_19_e.sce
@@ -0,0 +1,9 @@
+//example 1.19<e>

+//determine whether the following signals are power or energy signal power and energy

+clc ;

+t=0:0.01:100;

+x=t;

+T=2;

+P=(integrate('t^2','t',0,T))/(T);

+disp(P,'The power of the signal is:');

+disp('As t tends to infinity energy also tends to infinity but power remains finite hence it is power signal');

diff --git a/3812/CH1/EX1.2.a/1_2_a.sce b/3812/CH1/EX1.2.a/1_2_a.sce
new file mode 100644
index 000000000..14681b23a
--- /dev/null
+++ b/3812/CH1/EX1.2.a/1_2_a.sce
@@ -0,0 +1,16 @@
+//example 1_2<a>

+//sketch the following signal x(3t)

+clc;

+clear all;

+t=-1/3:0.0001:1/3;

+for i=1:length(t)

+if t(i)<0 then

+x(i)=1+3*t(i);

+else

+x(i)=1-3*t(i);

+end

+end

+plot2d(t,x)

+plot (t,x, 'red' );

+xtitle('required figure','t','x(3*t)');

+xgrid();

diff --git a/3812/CH1/EX1.2.b/1_2_b.sce b/3812/CH1/EX1.2.b/1_2_b.sce
new file mode 100644
index 000000000..7e5d5fdff
--- /dev/null
+++ b/3812/CH1/EX1.2.b/1_2_b.sce
@@ -0,0 +1,16 @@
+//example 1_2<b>

+//sketch the following signal x(3t+2)

+clc;

+clear all;

+t=-1:0.0001:-1/3;

+for i=1:length(t)

+if t(i)<-2/3 then

+x(i)=3+3*t(i);

+else

+x(i)=-1-3*t(i);

+end

+end

+plot(t,x)

+plot(t,x, 'red' );

+xtitle('required figure','t','x(3*t+2)');

+xgrid();

diff --git a/3812/CH1/EX1.2.c/1_2_c.sce b/3812/CH1/EX1.2.c/1_2_c.sce
new file mode 100644
index 000000000..a0febffac
--- /dev/null
+++ b/3812/CH1/EX1.2.c/1_2_c.sce
@@ -0,0 +1,16 @@
+//example 1_2<c>

+//sketch the following signal x(-2t-1)

+clc;

+clear all;

+t=-1:0.0001:0;

+for i=1:length(t)

+if t(i)>=-1/2 then

+x(i)=-2*t(i);

+else

+x(i)=(2*t(i))+2;

+end

+end

+plot(t,x)

+plot(t,x, 'red' );

+xtitle('required figure','t','x(-2*t-1)');

+xgrid();

diff --git a/3812/CH1/EX1.23/1_23.sce b/3812/CH1/EX1.23/1_23.sce
new file mode 100644
index 000000000..e1ec469d3
--- /dev/null
+++ b/3812/CH1/EX1.23/1_23.sce
@@ -0,0 +1,15 @@
+//Example 1.23

+//Find the even and odd components of the signal x(t)=(e^-2t)*cos(t)

+clc;

+clear all;

+t=-10:.1:10;

+for j=1:length(t)

+i=t(j);

+x(j)=(exp(-2*i))*cos(i);

+y(j)=(exp(2*i))*cos(i);

+e(j)=(1/2)*(x(j)+y(j));

+o(j)=(1/2)*(x(j)-y(j));

+end

+disp('In the plot even component is in red and odd component is in blue')

+plot(t,e,'red')

+plot(t,o,'blue')

diff --git a/3812/CH1/EX1.25.a/1_25_a.sce b/3812/CH1/EX1.25.a/1_25_a.sce
new file mode 100644
index 000000000..d992c263a
--- /dev/null
+++ b/3812/CH1/EX1.25.a/1_25_a.sce
@@ -0,0 +1,32 @@
+//Example 1.25<a>

+//To check whether the given discrete system is a Linear System (or) Non-Linear System y(t)= t*x(t)

+clear;

+clc;

+x1=[1,1,1,1];

+x2=[2,2,2,2];

+a=1;

+b=1;

+for t=1:length(x1)

+x3(t)=a*x1(t)+b*x2(t);

+end

+for t=1:length(x1)

+y1(t)=t*x1(t);

+y2(t)=t*x2(t);

+y3(t)=t*x3(t);

+end

+for t=1:length(y1)

+z(t)=a*y1(t)+b*y2(t);

+end

+count=0;

+for n=1:length(y1)

+if(y3(t)==z(t))

+count=count+1;

+end

+end

+if(count==length(y3))

+disp('Since It satisifies the superposition principle')

+disp('The given system is a Linear system')

+else

+disp('Since It does not satisify the superposition principle')

+disp('The given system is a Non-Linear system')

+end

diff --git a/3812/CH1/EX1.25.b/1_25_b.sce b/3812/CH1/EX1.25.b/1_25_b.sce
new file mode 100644
index 000000000..6e081b1ad
--- /dev/null
+++ b/3812/CH1/EX1.25.b/1_25_b.sce
@@ -0,0 +1,20 @@
+//Example 1.25<b>

+//Check whether the following signal is linear or not.

+clear ;

+close ;	

+clc ;

+T =20; //length of the signal

+for n=1: T

+x1(n)=n;x2(n)=2*n;

+y1(n)=x1(n)*x1(n);

+y2(n)=x2(n)*x2(n);

+end

+z=y1+y2;

+for n =1: T

+y3(n)=( x1(n)+x2(n)) ^2;

+end

+if z== y3 then

+disp('The following signal is linear');

+else

+disp ( 'The following signal is non linear');

+end

diff --git a/3812/CH1/EX1.25.d/1_25_d.sce b/3812/CH1/EX1.25.d/1_25_d.sce
new file mode 100644
index 000000000..14174bddb
--- /dev/null
+++ b/3812/CH1/EX1.25.d/1_25_d.sce
@@ -0,0 +1,32 @@
+//Example 1.25(d)

+//To check whether the given discrete system is a Linear System (or) Non-Linear System y[n])= 2*x[n]-3

+clear;

+clc;

+x1=[1,1,1,1];

+x2=[2,2,2,2];

+a=1;

+b=1;

+for n=1:length(x1)

+x3(n)=a*x1(n)+b*x2(n);

+end

+for n=1:length(x1)

+y1(n)=2*x1(n)-3;

+y2(n)=2*x2(n)-3;

+y3(n)=2*x3(n)-3;

+end

+for n=1:length(y1)

+z(n)=a*y1(n)+b*y2(n);

+end

+count=0;

+for n=1:length(y1)

+if(y3(n)==z(n))

+count=count+1;

+end

+end

+if(count==length(y3))

+disp('Since It satisifies the superposition principle')

+disp('The given system is a Linear system')

+else

+disp('Since It does not satisify the superposition principle')

+disp('The given system is a Non-Linear system')

+end

diff --git a/3812/CH1/EX1.27.a/1_27_a.sce b/3812/CH1/EX1.27.a/1_27_a.sce
new file mode 100644
index 000000000..b7ef09bdc
--- /dev/null
+++ b/3812/CH1/EX1.27.a/1_27_a.sce
@@ -0,0 +1,17 @@
+//Example 1.27<a>

+//Determine whether the following system is time invariant or not

+clc;	

+clear all;	

+T =20;

+s =2;

+for n=1:T

+x(n)=n;

+y(n)=n*x(n);

+end

+IP=x(T-s);

+OP=y(T-s);

+if IP == OP then

+disp('The given system is time invariant');

+else

+disp('The given system is time variant');

+end

diff --git a/3812/CH1/EX1.29.a/1_29_a.sce b/3812/CH1/EX1.29.a/1_29_a.sce
new file mode 100644
index 000000000..a3afb9caf
--- /dev/null
+++ b/3812/CH1/EX1.29.a/1_29_a.sce
@@ -0,0 +1,16 @@
+//Example 1.29<a>:

+//Determination of stablility of a given system

+clear;

+clc;

+x=[1,2,3,4,0,2,1,3,5,8];

+Maximum_Limit=10;

+S=0;

+for t=0:Maximum_Limit-1

+S=S+t*x(t+1);

+end 

+if (S >Maximum_Limit)

+disp('Eventhough input is bounded output is unbounded')

+disp('The given system is unstable');

+else

+disp('The given system is stable');

+end

diff --git a/3812/CH1/EX1.31.d/1_31_d.sce b/3812/CH1/EX1.31.d/1_31_d.sce
new file mode 100644
index 000000000..dffdf48ae
--- /dev/null
+++ b/3812/CH1/EX1.31.d/1_31_d.sce
@@ -0,0 +1,7 @@
+//Example 1.31<d>

+//check the given signL is PERIODIC OR NOT e^(-2*t)*u(t)

+clc ;

+t=-1:.01:1;

+x=exp(-2*t);

+plot (t,x);

+disp ('(a)this shows that the given signal is not periodic which gives w0=1+j,complex no. the frequency of signal can never be complex it must have real value');

diff --git a/3812/CH1/EX1.35.a/1_35_a.sce b/3812/CH1/EX1.35.a/1_35_a.sce
new file mode 100644
index 000000000..9489016e6
--- /dev/null
+++ b/3812/CH1/EX1.35.a/1_35_a.sce
@@ -0,0 +1,16 @@
+//Example 1.35<a>

+//Find whether the given system is causal or not y(t)=x*sin(t).

+clear all;

+clc;

+t=-10:10;

+x=2;

+for i=1:length(t)

+x3(i)=x*sin(t(i));

+end

+causal=%t;

+for i=1:length (t)

+if t(i)<0 & x3(i)~=0 then

+noncausal=%f;

+end

+end

+disp (noncausal,"The statement that the system is noncausal is");

diff --git a/3812/CH1/EX1.36.f/1_36_f.sce b/3812/CH1/EX1.36.f/1_36_f.sce
new file mode 100644
index 000000000..05321f416
--- /dev/null
+++ b/3812/CH1/EX1.36.f/1_36_f.sce
@@ -0,0 +1,16 @@
+//Example 1.36<f>

+//Find whether the given signal is causal or not y(n)=x(n^2).

+clear all;

+clc;	

+n=-10:10;

+for i=1:length (n)

+x(i)=i;

+y(i)=(i.^2) ;

+end

+causal=%t;

+for i=1: length (n)

+if n(i)<0 &y(i)~=0 then

+causal=%f;

+end

+end

+disp(causal,"The statement that the system is causal is:");

diff --git a/3812/CH1/EX1.6.a/1_6_a.sce b/3812/CH1/EX1.6.a/1_6_a.sce
new file mode 100644
index 000000000..b5e0b2f63
--- /dev/null
+++ b/3812/CH1/EX1.6.a/1_6_a.sce
@@ -0,0 +1,14 @@
+//example 1.6<a>

+//draw the waveform of the signal x1(t)=u(t+2)

+clc ;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=-2 then

+x(i)=1;

+else

+x(i)=0;

+end

+end

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.6.b/1_6_b.sce b/3812/CH1/EX1.6.b/1_6_b.sce
new file mode 100644
index 000000000..6f6f31ac2
--- /dev/null
+++ b/3812/CH1/EX1.6.b/1_6_b.sce
@@ -0,0 +1,14 @@
+//draw the waveform of the signal x2(t)=u(t-2)

+clc;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=2 then

+x(i)=1;

+else

+x(i)=0;

+end

+end

+//figure

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.6.c/1_6_c.sce b/3812/CH1/EX1.6.c/1_6_c.sce
new file mode 100644
index 000000000..7a7a28e98
--- /dev/null
+++ b/3812/CH1/EX1.6.c/1_6_c.sce
@@ -0,0 +1,13 @@
+//draw the waveform of the signal x3(t)=u(-t)

+clc ;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)<=0 then

+x(i)=1;

+else

+x(i)=0;

+end

+end

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.6.d/1_6_d.sce b/3812/CH1/EX1.6.d/1_6_d.sce
new file mode 100644
index 000000000..40a5cec2a
--- /dev/null
+++ b/3812/CH1/EX1.6.d/1_6_d.sce
@@ -0,0 +1,13 @@
+//draw the waveform of the signal x4(t)=u(-2t+1)

+clc ;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)<=1/2 then

+x(i)=1;

+else

+x(i)=0;

+end

+end

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.6.e/1_6_e.sce b/3812/CH1/EX1.6.e/1_6_e.sce
new file mode 100644
index 000000000..4a8b9d889
--- /dev/null
+++ b/3812/CH1/EX1.6.e/1_6_e.sce
@@ -0,0 +1,14 @@
+clc ;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)<=-1/2 then

+x(i)=1;

+else

+x(i)=0;

+end

+end

+// f i g u r e

+f=scf(0);

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.6.f/1_6_f.sce b/3812/CH1/EX1.6.f/1_6_f.sce
new file mode 100644
index 000000000..0a221ae08
--- /dev/null
+++ b/3812/CH1/EX1.6.f/1_6_f.sce
@@ -0,0 +1,16 @@
+//Example 1.6<f>

+//draw the waveform of the signal x6(t)=u(t+2)-u(t-2)

+clc ;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=-2 & t(i)<=2 then

+x(i)=1;

+else

+x(i)=0;

+end

+end

+//figure

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

+

diff --git a/3812/CH1/EX1.6.g/1_6_g.sce b/3812/CH1/EX1.6.g/1_6_g.sce
new file mode 100644
index 000000000..88a8c588f
--- /dev/null
+++ b/3812/CH1/EX1.6.g/1_6_g.sce
@@ -0,0 +1,16 @@
+//Example 1.6<g>//

+//draw the waveform of the signal x7(t)=u(t)-2*u(t-1)+u(t-2)//

+clc ;

+clear all;

+t=-10:.001:10

+for i=1:length(t)

+if t(i)>=0 & t(i)<=1 then

+x(i)=1;

+end

+if t(i)>=1 & t(i)<=2 then

+x(i)=-1

+end

+end

+//figure

+plot2d(t,x);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.7.a/1_7_a.sce b/3812/CH1/EX1.7.a/1_7_a.sce
new file mode 100644
index 000000000..edb6f693c
--- /dev/null
+++ b/3812/CH1/EX1.7.a/1_7_a.sce
@@ -0,0 +1,14 @@
+//Example 1.7<a>

+//draw the waveform of the signal x1(t)=r(t-1)

+clc;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=0 then

+x(i)=t(i)+1;

+else

+x(i)=0;

+end

+end

+plot2d(x,t);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.7.b/1_7_b.sce b/3812/CH1/EX1.7.b/1_7_b.sce
new file mode 100644
index 000000000..ddf366f22
--- /dev/null
+++ b/3812/CH1/EX1.7.b/1_7_b.sce
@@ -0,0 +1,14 @@
+//Example 1.7<b>

+//draw the waveform of the signal x1(t)=r(t+1)

+clc;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=1 then

+x(i)=t(i)-1;

+else

+x(i)=0;

+end

+end

+plot2d(x,t);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.7.c/1_7_c.sce b/3812/CH1/EX1.7.c/1_7_c.sce
new file mode 100644
index 000000000..6431584f8
--- /dev/null
+++ b/3812/CH1/EX1.7.c/1_7_c.sce
@@ -0,0 +1,15 @@
+//Example 1.7<c>

+//draw the waveform of the signal x1(t)=r(-t)

+clc;

+clear all;

+t=-10:0.001:10;

+for i=1:length(t)

+if t(i)>=0  then

+x(i)=-t(i);

+else

+x(i)=0;

+end

+end

+//figure

+plot2d(x,t);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.7.d/1_7_d.sce b/3812/CH1/EX1.7.d/1_7_d.sce
new file mode 100644
index 000000000..36aa82c3b
--- /dev/null
+++ b/3812/CH1/EX1.7.d/1_7_d.sce
@@ -0,0 +1,15 @@
+//Example 1.7<d>

+//draw the waveform of the signal x1(t)=r(3t)

+clc;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=0 then

+x(i)=3*t(i);

+else

+x(i)=0;

+end

+end

+//figure

+plot2d(x,t);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.7.e/1_7_e.sce b/3812/CH1/EX1.7.e/1_7_e.sce
new file mode 100644
index 000000000..38db62da2
--- /dev/null
+++ b/3812/CH1/EX1.7.e/1_7_e.sce
@@ -0,0 +1,15 @@
+//Example 1.7<e>

+//draw the waveform of the signal x1(t)=r(-3t)

+clc;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=0 then

+x(i)=-3*t(i);

+else

+x(i)=0;

+end

+end

+//figure

+plot2d(x,t);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.7.f/1_7_f.sce b/3812/CH1/EX1.7.f/1_7_f.sce
new file mode 100644
index 000000000..6dba56f02
--- /dev/null
+++ b/3812/CH1/EX1.7.f/1_7_f.sce
@@ -0,0 +1,15 @@
+//Example 1.7<f>

+//draw the waveform of the signal x1(t)=r(3t+1)

+clc;

+clear all;

+t=-10:.001:10;

+for i=1:length(t)

+if t(i)>=-1/3 then

+x(i)=3*t(i)-1/3;

+else

+x(i)=0;

+end

+end

+//figure

+plot2d(x,t);

+xtitle('Required figure','t','x(t)')

diff --git a/3812/CH1/EX1.8.a/1_8_a.sce b/3812/CH1/EX1.8.a/1_8_a.sce
new file mode 100644
index 000000000..11d820c65
--- /dev/null
+++ b/3812/CH1/EX1.8.a/1_8_a.sce
@@ -0,0 +1,14 @@
+//Example 1.8<a>

+//draw the waveform of the signal x1(t)=r(t)-r(t-1)-u(t-1)

+clc;

+clear all;

+t=-10:0.001:10;

+for i=1:length(t)

+if t(i)>=0 & t(i)<1 then

+x(i)=t(i);

+else

+x(i)=0;

+end

+end

+plot2d(t,x)

+xtitle('Required figure','t','x(t)')