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@ -59,7 +59,7 @@ design_filter_order = ceil(temp_filter_order); |
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% Calculates epsilon parameter using the eq. 9-123 |
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% Calculates epsilon parameter using the eq. 9-123 |
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epsilon_parameter = 1/(10^(specification_min_stop_attenuation/10)-1)^(1/2); |
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epsilon_parameter = 1/(10^(specification_min_stop_attenuation/10)-1)^(1/2); |
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% Calculates alpha using the eq. ?? wtf is this? =========^^^^^^^^^^^^^^^^^^&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&========== |
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% Calculates alpha using the eq. 9-92 |
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alpha_parameter = asinh(1/epsilon_parameter)/design_filter_order; |
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alpha_parameter = asinh(1/epsilon_parameter)/design_filter_order; |
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% Calculates the frequency at which half power occurs using the eq. 9-139 |
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% Calculates the frequency at which half power occurs using the eq. 9-139 |
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@ -91,12 +91,12 @@ inverse_chebyshev_poles_Q = zeros([1 design_number_of_poles]); |
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% Calculates the Butterworth angles using the method suggested in chapter |
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% Calculates the Butterworth angles using the method suggested in chapter |
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% 9 (page 10) of the course notes and then uses them to calculate the |
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% 9 (page 10) of the course notes and then uses them to calculate the |
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% inverse Chebyshev poles |
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% Chebyshev poles |
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if mod(design_filter_order,2)~=0 % Odd number of poles |
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if mod(design_filter_order,2)~=0 % Odd number of poles |
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% First pole has a zero angle |
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% First pole has a zero angle |
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design_butterworth_angles(1,1)=0; |
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design_butterworth_angles(1,1)=0; |
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% The rest of the poles are scattered in the left half pane with |
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% The rest of the poles are scattered in the left half pane in equal |
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% equal angles |
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% angle arcs |
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% Theta is a helper parameter |
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% Theta is a helper parameter |
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theta=180/design_filter_order; |
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theta=180/design_filter_order; |
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@ -281,6 +281,7 @@ for i=1:design_number_of_poles |
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unit_low_pass_notch_resistors_5(1,i) = ... |
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unit_low_pass_notch_resistors_5(1,i) = ... |
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(4*inverse_chebyshev_poles_Q(1,i)^2)/ ... |
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(4*inverse_chebyshev_poles_Q(1,i)^2)/ ... |
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(normalized_transfer_function_zero^2-1); % Ohm |
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(normalized_transfer_function_zero^2-1); % Ohm |
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unit_low_pass_notch_resistors_4(1,i) = 1; % Ohm |
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unit_low_pass_notch_resistors_4(1,i) = 1; % Ohm |
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% Calculates the resistance of R3 using the eq. 7-155 |
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% Calculates the resistance of R3 using the eq. 7-155 |
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unit_low_pass_notch_resistors_3(1,i) = ... |
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unit_low_pass_notch_resistors_3(1,i) = ... |
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@ -449,51 +450,72 @@ ltiview(unit_transfer_function(1,1), unit_transfer_function(1,2), ... |
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hold off |
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hold off |
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Fs = 1000; % Sampling frequency |
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T = 1/Fs; % Sampling period |
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L = 1500; % Length of signal |
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t = (0:L-1)*T; % Time vector |
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input_signal_frequency = 2000; % Hz |
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input_signal_frequency = 2000; % Hz |
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input_signal_number_of_periods = 100000; |
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input_signal_T = input_signal_number_of_periods*(1/input_signal_frequency); |
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input_signal_duty_cycle = 20; |
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input_signal_duty_cycle = 20; |
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input_signal_Fs = 80000; |
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input_signal_dt = 1/input_signal_Fs; |
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input_signal_t = 0:input_signal_dt:input_signal_T-input_signal_dt; |
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input_square_wave = (1+square(2*pi*input_signal_frequency*input_signal_t, ... |
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number_of_periods_sampled = 120000; |
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sampling_time_seconds = number_of_periods_sampled* ... |
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(1/input_signal_frequency); % s |
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sampling_frequency_Fs = 80000; % Hz |
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sampling_period_T = 1/sampling_frequency_Fs; % s |
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sampling_time_vector = 0:sampling_period_T: ... |
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sampling_time_seconds-sampling_period_T; |
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sampling_length_L = length(sampling_time_vector); |
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frequency_vector = sampling_frequency_Fs/sampling_length_L* ... |
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(0:(sampling_length_L/2)); |
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input_square_wave = (1+ ... |
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square(2*pi*input_signal_frequency*sampling_time_vector, ... |
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input_signal_duty_cycle))/2; |
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input_signal_duty_cycle))/2; |
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system_output = lsim(total_transfer_function, input_square_wave, input_signal_t); |
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system_output = lsim(total_transfer_function, input_square_wave, ... |
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sampling_time_vector); |
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% Plots only the first 10 periods |
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% Plots only the first 10 periods |
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temp = 10*input_signal_Fs/input_signal_frequency; |
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temp = 10*sampling_frequency_Fs/input_signal_frequency; |
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figure(1) |
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figure(1) |
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plot(input_signal_t(1:temp), input_square_wave(1:temp), ... |
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plot(sampling_time_vector(1:temp), input_square_wave(1:temp), ... |
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input_signal_t(1:temp), system_output(1:temp)); |
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sampling_time_vector(1:temp), system_output(1:temp)); |
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grid on |
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grid on |
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% Plots the power spectrum of the input signal |
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input_square_wave_fft = fft(input_square_wave); |
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input_square_wave_fft = fft(input_square_wave); |
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L = length(input_signal_t); |
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Pyy = input_square_wave_fft.*conj(input_square_wave_fft)/sampling_length_L; |
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P2 = abs(input_square_wave_fft/L); |
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P1 = P2(1:L/2+1); |
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P1(2:end-1) = 2*P1(2:end-1); |
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f = input_signal_Fs*(0:(L/2))/L; |
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figure(2) |
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figure(2) |
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%plot(f,P1) |
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semilogx(frequency_vector,Pyy(1:sampling_length_L/2+1)) |
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semilogx(f,P1) |
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grid on |
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grid on |
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system_output_fft = fft(system_output, length(input_signal_t)); |
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% Plots the power spectrum of the output signal |
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P2 = abs(system_output_fft/L); |
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system_output_fft = fft(system_output, length(sampling_time_vector)); |
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P1 = P2(1:L/2+1); |
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Pyy = system_output_fft.*conj(system_output_fft)/sampling_length_L; |
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P1(2:end-1) = 2*P1(2:end-1); |
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figure(3) |
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figure(3) |
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%plot(f, P11) |
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semilogx(frequency_vector,Pyy(1:sampling_length_L/2+1)) |
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semilogx(f,P1) |
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grid on |
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grid on |
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%filter_fft = fft(total_transfer_function); |
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%{ |
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asdf = 1:length(frequency_vector); |
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for i=1:length(frequency_vector) |
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if i<175000 |
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asdf(i) = 1; |
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elseif mod(i,200)==0 |
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[asdf(i),phase] = ... |
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bode(total_transfer_function, ... |
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frequency_vector(i)*2*pi); |
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else |
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asdf(i) = 0; |
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end |
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%{ |
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if mod(i,10000)==0 |
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disp(i) |
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end |
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%} |
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end |
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figure(4) |
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semilogx(frequency_vector,asdf,'.',frequency_vector,P1,'-') |
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grid on |
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%} |
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% Clears unneeded variable from workspace |
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% Clears unneeded variable from workspace |
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clear low_frequency |
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clear low_frequency |
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