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+clc;
+//page 608
+//problem 12.2
+
+//Baseband cutoff signal fM = 4 kHz
+fM = 4 * 10^3;
+
+//White noise power spectral density n
+n = 2*10^(-9);
+
+// Part (a)
+
+//Input Signal energy Si = 0.001
+Si_a = 0.001;
+
+//No of levels used for PCM Coding M = 8
+M_a = 8;
+
+N_a = log2(M_a);
+
+//Input SNR is SNR_ip
+SNR_ip = Si_a/(n*fM);
+
+//Output SNR is SNR_op
+SNR_op = (2^(2*N_a))/(1 + (2^(2*N_a + 1))*erfc((SNR_ip*(1/(2*N_a))))^0.5);
+
+disp('Input SNR for (a) is '+string(10*log10(SNR_ip))+' dB');
+disp('Output SNR (a) is '+string(10*log10(SNR_op))+' dB');
+
+// Part (b)
+
+//Input Signal energy Si = 0.001
+Si_b = 0.001;
+
+//No of levels used for PCM Coding M = 256
+M_b = 256;
+
+N_b = log2(M_b);
+
+//Input SNR is SNR_ip_b
+SNR_ip_b = Si_b/(n*fM);
+
+//Output SNR is SNR_op_b
+SNR_op_b = (2^(2*N_b))/(1 + (2^(2*N_b + 1))*erfc((SNR_ip_b*(1/(2*N_b))))^0.5);
+
+//Unfortunately in scilab the function erfc approximates the output value to a larger extent due to which an exact value cannot be obtained.
+//The difference in the textbook answer and obatined answer is significant because of converting the answer into dB.
+
+disp('Input SNR for (b) is '+string(10*log10(SNR_ip_b))+' dB');
+disp('Output SNR for (b) is '+string(10*log10(SNR_op_b))+' dB');
+
+// Part (c)
+
+//Input Signal energy Si = 0.01
+Si_c = 0.01;
+
+//No of levels used for PCM Coding M = 256
+M_c = 256;
+
+N_c = log2(M_c);
+
+//Input SNR is SNR_ip_c
+SNR_ip_c = Si_c/(n*fM);
+
+//Output SNR is SNR_op_c
+SNR_op_c = (2^(2*N_c))/(1 + (2^(2*N_c + 1))*erfc((SNR_ip_c*(1/(2*N_c))))^0.5);
+
+disp('Input SNR for (c) is '+string(10*log10(SNR_ip_c))+' dB');
+disp('Output SNR for (c) is '+string(10*log10(SNR_op_c))+' dB');
+
+