Low pass response to input signal init

Low Pass Inverse Chebyshev/low_pass_design.m

@@ -411,29 +411,95 @@ fprintf(['\n' '===== GAIN ADJUSTMENT =====' '\n' ...
 
 % ========== GAIN ADJUSTMENT END ==========
 
-%% ========== TRANSFER FUNCTIONS START ==========
+%% ========== TRANSFER FUNCTIONS STUDY START ==========
 
 total_transfer_function = series(unit_transfer_function(1,1), ...
     unit_transfer_function(1,2));
 total_transfer_function = total_transfer_function*unit_adjustment_gain;
 
+low_frequency = 10;
 %{
+% Plots each unit's frequency response
+for i=1:design_number_of_poles
+    plot_transfer_function(unit_transfer_function(1,i), ...
+        (low_frequency));
+end
+
+% Plots the total filter frequency response
 plot_transfer_function(total_transfer_function, ...
-    [10 ...
+    [low_frequency ...
     specification_pass_frequency ...
     design_half_power_radial_frequency/(2*pi) ...
     specification_stop_frequency]);
+
+% Plots the total filter attenuation function
+plot_transfer_function(inv(total_transfer_function), ...
+    [low_frequency ...
+    specification_pass_frequency ...
+    design_half_power_radial_frequency/(2*pi) ...
+    specification_stop_frequency]);
+%}
+%{
+ltiview(unit_transfer_function(1,1));
+ltiview(unit_transfer_function(1,2));
+ltiview(total_transfer_function);
+ltiview(unit_transfer_function(1,1), unit_transfer_function(1,2), ...
+    total_transfer_function);
 %}
 
-%ltiview(unit_transfer_function(1,1));
+hold off
-%ltiview(unit_transfer_function(1,2));
+
-%ltiview(total_transfer_function);
+Fs = 1000;            % Sampling frequency                    
-%ltiview(unit_transfer_function(1,1), unit_transfer_function(1,2), ...
+T = 1/Fs;             % Sampling period       
-    %total_transfer_function);
+L = 1500;             % Length of signal
+t = (0:L-1)*T;        % Time vector
+
+input_signal_frequency = 2000; % Hz
+input_signal_number_of_periods = 100000;
+input_signal_T = input_signal_number_of_periods*(1/input_signal_frequency);
+input_signal_duty_cycle = 20;
+input_signal_Fs = 80000;
+input_signal_dt = 1/input_signal_Fs;
+input_signal_t = 0:input_signal_dt:input_signal_T-input_signal_dt;
+
+input_square_wave = (1+square(2*pi*input_signal_frequency*input_signal_t, ...
+    input_signal_duty_cycle))/2;
+
+system_output = lsim(total_transfer_function, input_square_wave, input_signal_t);
+% Plots only the first 10 periods
+temp = 10*input_signal_Fs/input_signal_frequency;
+figure(1)
+plot(input_signal_t(1:temp), input_square_wave(1:temp), ...
+    input_signal_t(1:temp), system_output(1:temp));
+grid on
+
+input_square_wave_fft = fft(input_square_wave);
+L = length(input_signal_t);
+P2 = abs(input_square_wave_fft/L);
+P1 = P2(1:L/2+1);
+P1(2:end-1) = 2*P1(2:end-1);
+f = input_signal_Fs*(0:(L/2))/L;
+figure(2)
+%plot(f,P1)
+semilogx(f,P1)
+grid on
+
+system_output_fft = fft(system_output, length(input_signal_t));
+P2 = abs(system_output_fft/L);
+P1 = P2(1:L/2+1);
+P1(2:end-1) = 2*P1(2:end-1);
+figure(3)
+%plot(f, P11)
+semilogx(f,P1)
+grid on
+
+%filter_fft = fft(total_transfer_function);
 
 % Clears unneeded variable from workspace
+clear low_frequency
 clear -regexp _numerator$
 clear -regexp _denominator$
 clear -regexp _transfer_function$
+clear -regexp ^input_signal_
 
-% ========== TRANSFER FUNCTIONS END ==========
+% ========== TRANSFER FUNCTIONS STUDY END ==========