Added LiveScripts, graphs. Code for BPSK and plots refactored. #1

bpsk_ber.m

@@ -37,12 +37,12 @@
     EbN0 = 10^(SNR(snr)/10); % 
     AWGN_sigma = sqrt(1/(EbN0*2));
     AWGN = AWGN_sigma * randn(1, length(bpsk_coded_signal));
-    primljeni_signal = bpsk_coded_signal + AWGN;
+    received_signal = bpsk_coded_signal + AWGN;
     % Decider's output
-    bpsk_dekodirani_biti = primljeni_signal >= 0;
+    bpsk_decoded_bits = received_signal >= 0;
 %---------------------------------------------------------------
 %   Received bits with error:
-    difference = (channel_bits) - (bpsk_dekodirani_biti);
+    difference = (channel_bits) - (bpsk_decoded_bits);
 %   Num of errors and received bits in curr. iteration:
     tot_err = sum(abs(difference));
     tot_bits = length(bpsk_coded_signal);

bpsk_init.m

@@ -0,0 +1,41 @@
+function [data_bits, t, Ts, Tb, bpsk_coded_signal, Carrier] = bpsk_init(num_data_bits, SNR, F_carrier, reset, print)
+%BPSK_INIT Summary of this function goes here
+% 
+if(reset)
+    close all; % close figure windows
+end
+if(print)
+    fprintf('\n* BPSK simulation *\n')
+    fprintf('Number of data bits: %d \n', num_data_bits)
+    fprintf('SNR (dB): %.1f \n', SNR)
+end
+%----------------------------------------------------------
+% Generate random data bits for transfer
+% >> TODO: add input for some standard signals
+data_bits = randn(1, num_data_bits) >= 0;
+% random array of -1 and 1
+% condition >=0 turns this array into a 0 and 1 array
+%------------------------------------------------------------
+% Other data
+Rb = 1000; % Bit rate
+% Rb = speed (rate) of bits per sec = Fm (max signal frequency in spectrum)
+A = 1; % Signal amplitude on Connection line
+num_samples_per_bit = 20; % = Tb/Ts; (taken at will, has to be >= 2)
+Fs = num_samples_per_bit * Rb;  % Sampling frequency (Hz)
+Ts=1/Fs; % Sample duration (sec)
+Tb=1/Rb; % Bit duration (sec)
+t = 0 : Ts : Tb * num_data_bits - Ts; % Time axis
+%------------------------------------------------------------
+% Form signal that's sent through the coded channel
+bpsk_coded_bit = zeros(1,Tb*1/Ts);
+bpsk_coded_signal = zeros(1,num_data_bits*length(bpsk_coded_bit));
+% signal is 'spread' (sampled) during each data bit duration
+for cntr = 1 : num_data_bits
+    bpsk_coded_bit = A*(2*data_bits(cntr) - 1) *ones(1,num_samples_per_bit);
+    % values are -A are +A, i.e. -1 and +1 (phase change 0 and pi)
+    bpsk_coded_signal((cntr-1)*num_samples_per_bit +1 : (cntr)*num_samples_per_bit) = bpsk_coded_bit;
+end
+%F_carrier = 500; % Carrier frequency (Hz) (set at will)
+Carrier = cos(2*pi*F_carrier*t);
+end
+

bpsk_transmission_system.m

@@ -1,123 +1,68 @@
-%  BPSK system
+%  BPSK system model
 %------------------------------------------------------------
-clear all; close all; %#ok<CLALL>
-% clear previous data and close windows
-%------------------------------------------------------------
-fprintf('\n BPSK simulation \n')
-%------------------------------------------------------------
-% Initialization
-% 1 - num of data bits to transfer: 
-num_data_bits = 16;
-fprintf('BPSK - num of data bits to transfer: %d \n', num_data_bits)
+% Configure Input parameters:
+fprintf("\nInput parameters:\n")
+% 1 - Number of data bits to transfer:
+num_data_bits = [16, 64]; % Data bit sequence lengths
+fprintf(['Data bit sequence lengths =' repmat(' %d',1,numel(num_data_bits))], num_data_bits)
+fprintf("\n")
 % 2 - Signal-to-noise ratio in the channel - determined by AWGN level:
-SNR = 0; %:2:10; % SNR (dB) range
-% TODO: add looping
-fprintf('BPSK - SNR: %d \n', SNR)
-%----------------------------------------------------------
-% Generate random data bits for transfer
-% TODO: add input for some standard signaals
-data_bits = randn(1, num_data_bits) >= 0;
-% random array of -1 and 1
-% condition >=0 turns this array into a 0 and 1 array
-%------------------------------------------------------------
-% Other data
-Rb = 1000; % Bit rate
-% Rb = speed (rate) of bits per sec = Fm (max signal frequency in spectrum) 
-A = 1; % Signal amplitude on Connection line
-num_samples_per_bit = 20; % = Tb/Ts; (taken at will, has to be >= 2)
-Fs = num_samples_per_bit * Rb;  % Sampling frequency (Hz)
-Ts=1/Fs; % Sample duration (sec)
-Tb=1/Rb; % Bit duration (sec)
-t = 0 : Ts : Tb * num_data_bits - Ts; % Time axis
-%------------------------------------------------------------
-% Form signal that's sent through the coded channel
-bpsk_coded_bit = zeros(1,Tb*1/Ts);
-bpsk_coded_signal = zeros(1,num_data_bits*length(bpsk_coded_bit)); 
-% signal is 'spread' (sampled) during each data bit duration
-for cntr = 1 : num_data_bits 
-   bpsk_coded_bit = A*(2*data_bits(cntr) - 1) *ones(1,num_samples_per_bit);
-   % values are -A are +A, i.e. -1 and +1 (phase change 0 and pi)
-   bpsk_coded_signal((cntr-1)*num_samples_per_bit +1 : (cntr)*num_samples_per_bit) = bpsk_coded_bit;
+SNR = -5:5:5; % SNR (dB) range
+fprintf(['SNR (dB) =' repmat(' %.1f',1,numel(SNR))], SNR)
+fprintf("\n")
+% 3 - Carrier frequency (Hz)
+F_carrier = 1000;
+fprintf("Carrier frequency (Hz) = %d", F_carrier)
+fprintf("\n")
+%% LOOP
+for iter1 = 1 : length(num_data_bits)
+    for iter2 = 1 : length(SNR)
+        if(iter1 == 1 && iter2 == 1)
+            close_figs = true;
+        else
+            close_figs = false;
+        end
+        [data_bits, time, Ts, Tb, bpsk_coded_signal, Carrier] = ...
+            bpsk_init(num_data_bits(iter1), SNR(iter2), F_carrier, close_figs, true);
+        %------------------------------------------------------------
+        % Transmitter TX - Frequency multiplier
+        % Frequency multiplier output
+        bpsk_modulated_signal = bpsk_coded_signal .* Carrier; 
+        %---------------------------------------------------------------
+        % Line/channel 
+        EbN0 = 10^(SNR(iter2)/10); % 
+        AWGN_sigma = sqrt(1/(EbN0*2));
+        AWGN = AWGN_sigma * randn(1, length(bpsk_modulated_signal));
+        %---------------------------------------------------------------
+        % Adding Gaussian noise:
+        received_signal = bpsk_modulated_signal + AWGN; 
+        %---------------------------------------------------------------
+        signal_time_plots(['Input Signals' ' ' num2str(iter1) ' ' num2str(iter2)], ...
+            time, data_bits, bpsk_coded_signal, bpsk_modulated_signal, AWGN);
+
+        %---------------------------------------------------------------
+        % Receiver RX - Frequency multiplier (synchronous demodulation)
+        Rx_fmultiplier_output = received_signal .* Carrier; 
+        %---------------------------------------------------------------
+        % Receiver RX - Integrator
+        interval = 0 : Ts : Tb-Ts; 
+        % integration boundaries define Tb (data bit duration)
+        Integrator_output = zeros(1,(length(Rx_fmultiplier_output)/(Tb/Ts)));
+        % (length(Rx_fmultiplier_output)/(Tb/Ts)) == num_data_bits
+        for i = 0 : (length(Rx_fmultiplier_output)/(Tb/Ts))-1  % num of bits
+             Integrator_output(i+1) = trapz(interval, ...
+                 Rx_fmultiplier_output( (i*(Tb/Ts)+1) : ((i+1)*(Tb/Ts))) );
+        end
+        % trapz does numerical integration using trapezoidal method
+        % on data bit duration interval
+        %------------------------------------------------------------
+        % Receiver RX - decision making using Treshold
+        % 0 is Treshold, decision: 0 for -1, 1 for 1
+        Decider_output = (Integrator_output >= 0); 
+        % Decider_output yealds received data bits
+        %------------------------------------------------------------
+        signal_time_plots(['Output Signals' ' ' num2str(iter1) ' ' num2str(iter2)], ...
+            time, received_signal, Rx_fmultiplier_output, Integrator_output, Decider_output);
+    end
 end
-%---------
-% Plots
-figure(1)
-subplot(4,1,1); stem(data_bits);
-xlabel('Bits'); ylabel('Logical values'); title('Input data bits');
-axis([0, num_data_bits, -0.5, 1.5]);
-subplot(4,1,2); plot(t, bpsk_coded_signal, 'LineWidth',2); grid on;
-xlabel('Time'); ylabel('Amplitude'); title('Coded signal');
-maxTime=max(t); 
-maxAmp=max(bpsk_coded_signal);
-minAmp=min(bpsk_coded_signal);
-axis([0,maxTime,minAmp-0.5,maxAmp+0.5]);
-%------------------------------------------------------------
-% Transmitter TX - Frequency multiplier
-F_carrier = 500; % Carrier frequency (Hz) (set at will)
-% TODO: add as input
-Carrier = cos(2*pi*F_carrier*t);
-% Frequency multiplier output
-bpsk_modulated_signal = bpsk_coded_signal .* Carrier; 
-%---------
-% Plot
-subplot(4,1,3); plot(t, bpsk_modulated_signal, 'LineWidth',2.5); grid on;
-xlabel('Time'); ylabel('Amplitude'); title('Modulated signal');
-maxTime=max(t); 
-maxAmp=max(bpsk_modulated_signal);
-minAmp=min(bpsk_modulated_signal);
-axis([0,maxTime,minAmp-0.5,maxAmp+0.5]);
-%---------------------------------------------------------------
-% Line/channel 
-EbN0 = 10^(SNR/10); % 
-AWGN_sigma = sqrt(1/(EbN0*2));
-AWGN = AWGN_sigma * randn(1, length(bpsk_modulated_signal));
-%---------
-% Plot
-subplot(4,1,4); plot(t, AWGN, 'LineWidth',2); grid on;
-xlabel('Time'); ylabel('Amplitude'); title('White Gaussian noise');
-maxTime=max(t); 
-maxAmp=max(AWGN);
-minAmp=min(AWGN);
-axis([0,maxTime,minAmp-0.5,maxAmp+0.5]);
-% Adding Gaussian noise:
-received_signal = bpsk_modulated_signal + AWGN; 
-%---------------------------------------------------------------
-% Receiver RX - Frequency multiplier (synchronous demodulation)
-Rx_fmultiplier_output = received_signal .* Carrier; 
-%---------------------------------------------------------------
-% Receiver RX - Integrator
-interval = 0 : Ts : Tb-Ts; 
-% integration boundaries define Tb (data bit duration)
-Integrator_output = zeros(1,(length(Rx_fmultiplier_output)/(Tb/Ts)));
-% (length(Rx_fmultiplier_output)/(Tb/Ts)) == num_data_bits
-for i = 0 : (length(Rx_fmultiplier_output)/(Tb/Ts))-1  % num of bits
-     Integrator_output(i+1) = trapz(interval, Rx_fmultiplier_output( (i*(Tb/Ts)+1) : ((i+1)*(Tb/Ts))) );
-end
-% trapz does numerical integration using trapezoidal method
-% on data bit duration interval
-%------------------------------------------------------------
-% Receiver RX - Odlucivac - Treshold
-% 0 is Treshold, decision: 0 for -1, 1 for 1
-Decider_output = (Integrator_output >= 0); 
-% Decider_output yealds received data bits
-%---------
-% Plot
-figure(2)
-subplot(4,1,1); plot(t, received_signal, 'LineWidth',2); grid on;
-xlabel('Time'); ylabel('Amplitude'); title('Receiver RX');
-maxTime=max(t); 
-maxAmp=max(received_signal);
-minAmp=min(received_signal);
-axis([0,maxTime,minAmp-1,maxAmp+1]);  
-subplot(4,1,2); plot(t, Rx_fmultiplier_output, 'LineWidth',2); grid on;
-xlabel('Time'); ylabel('Amplitude'); title('RX F.Multiplier output');
-maxTime=max(t); 
-maxAmp=max(Rx_fmultiplier_output);
-minAmp=min(Rx_fmultiplier_output);
-axis([0,maxTime,minAmp-1,maxAmp+1]);  
-subplot(4,1,3); stem(Integrator_output, 'MarkerFaceColor',[0.4,0.4,1]);
-grid on; xlabel('Bits'); ylabel('Amplitude'); title('Integrator output');
-subplot(4,1,4); stem(Decider_output);
-xlabel('Bits'); ylabel('Logical values'); title('Received data bits');
-axis([0, num_data_bits, -0.5, 1.5]); 
 %--THE-END-------------------------------------------------------

signal_time_plots.m

@@ -0,0 +1,59 @@
+function signal_time_plots(sel_fig, time, sig1, sig2, sig3, sig4)
+%SIGNAL_PLOTS Summary of this function goes here
+%  
+    if(contains(sel_fig, 'Input Signals'))
+        figure('Name',sel_fig,'NumberTitle','off');
+        % Plot 1
+        subplot(4,1,1); stem(sig1);
+        xlabel('Bits'); ylabel('Logical values'); title('Input data bits');
+        axis([0, length(sig1), -0.5, 1.5]);
+        % Plot 2
+        subplot(4,1,2); plot(time, sig2, 'LineWidth',2); grid on;
+        xlabel('Time'); ylabel('Amplitude'); title('Coded signal');
+        maxTime=max(time);
+        maxAmp=max(sig2);
+        minAmp=min(sig2);
+        axis([0,maxTime,minAmp-0.5,maxAmp+0.5]);
+        % Plot 3
+        subplot(4,1,3); plot(time, sig3, 'LineWidth',2.5); grid on;
+        xlabel('Time'); ylabel('Amplitude'); title('Modulated signal');
+        maxTime=max(time); 
+        maxAmp=max(sig3);
+        minAmp=min(sig3);
+        axis([0,maxTime,minAmp-0.5,maxAmp+0.5]);
+        % Plot 4
+        subplot(4,1,4); plot(time, sig4, 'LineWidth',2); grid on;
+        xlabel('Time'); ylabel('Amplitude'); title('White Gaussian noise');
+        maxTime=max(time); 
+        maxAmp=max(sig4);
+        minAmp=min(sig4);
+        axis([0,maxTime,minAmp-0.5,maxAmp+0.5]);
+    elseif(contains(sel_fig, 'Output Signals'))
+        figure('Name',sel_fig,'NumberTitle','off');
+        % Plot 1
+        subplot(4,1,1); plot(time, sig1, 'LineWidth',2); grid on;
+        xlabel('Time'); ylabel('Amplitude'); title('Receiver RX');
+        maxTime=max(time); 
+        maxAmp=max(sig1);
+        minAmp=min(sig1);
+        axis([0,maxTime,minAmp-1,maxAmp+1]); 
+        % Plot 2
+        subplot(4,1,2); plot(time, sig2, 'LineWidth',2); grid on;
+        xlabel('Time'); ylabel('Amplitude'); title('RX F.Multiplier output');
+        maxTime=max(time); 
+        maxAmp=max(sig2);
+        minAmp=min(sig2);
+        axis([0,maxTime,minAmp-1,maxAmp+1]); 
+        % Plot 3
+        subplot(4,1,3); stem(sig3, 'MarkerFaceColor',[0.4,0.4,1]);
+        grid on; xlabel('Bits'); ylabel('Amplitude'); title('Integrator output');
+        minAmp=min(sig3);
+        maxAmp=max(sig3);
+        axis([0, length(sig3), minAmp*1.5, maxAmp*1.5]);
+        % Plot 4
+        subplot(4,1,4); stem(sig4);
+        xlabel('Bits'); ylabel('Logical values'); title('Received data bits');
+        axis([0, length(sig4), -0.5, 1.5]);
+    end
+end
+