1 files changed, 27 insertions, 0 deletions
diff --git a/3446/CH4/EX4.5/Ex4_5.sce b/3446/CH4/EX4.5/Ex4_5.sce
new file mode 100644
index 000000000..bc3778440
--- /dev/null
+++ b/3446/CH4/EX4.5/Ex4_5.sce
@@ -0,0 +1,27 @@
+// Exa 4.5
+// To determine choice of modulation scheme if no-error correction coding is used.
+
+clc;
+clear all;
+
+S_No=53; //dB-Hz
+R=9.6*10^3; //bps
+BW=4.8*10^3; //Khz
+Pb=10^-5; //BER<=10^-5;
+
+//solution
+disp("Since the required data rate of 9.6 kbps is more than the available bandwidth of 4.8 kHz, the channel is bandwidth-limited.");
+Eb_No=S_No-10*log10(R); //dB
+// Try for 8-PSK modulation scheme
+M=8;
+Ps=log2(M)*Pb; //Max ps
+Es_No=log2(M)*10^(0.1*Eb_No);
+//Ps(8)=2*Q(sqrt(2*Es_No)*sin(%pi/8));
+//2*Q(sqrt(2*Eb_No))=erfc(sqrt(Eb_No));  //Refer EQn C(7) from appendix C
+
+Ps8=erfc(sqrt(Es_No)*sin(%pi/8));
+disp("");
+printf(' Symbol error rate is given as %.5f \n ',Ps);
+printf('The ratio of signal energy to noise is %.2f \n ',Es_No);
+printf('Symbol error rate for 8-PSK  is %.5f \n ',Ps8);
+disp("As symbol error rate for 8-PSK modulation is lower than threshold value. so, We can use 8-PSK modulation.")