Use output of a loop as its input to a filter

Question

S 2024-1-22

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2072611-use-output-of-a-loop-as-its-input-to-a-filter

评论： Sulaymon Eshkabilov 2024-1-22

I am trying to build a cascade of filters so that the output of one is the input to the next one. The filters are all bandpass filters and I want to be able to have an input signal and have it run through all 32 bandpass filters in series. I also ultimately want to be able to specify a filter number to be able to look at the output after that specific filter number. This is what I have so far, I am having issues figuring out how to make the bottom loop apply the filter desgined in the top part of the code and how to make a loop which takes its own output and uses it as input. Thank you for your time! This is what I have:

close all
fs = 16e3;
numFilts = 32;
filter_number = 10;
%range = [50 8000];
CF1=linspace(50, 8000, 32) -50;
CF2=linspace(50, 8000, 32) +50;
for ii = 1:numel(CF1)-2
    bpfilt{ii} = designfilt( ...
        'bandpassfir', ...
        'FilterOrder',20, ...
        'CutoffFrequency1',CF1(ii+1), ...
        'CutoffFrequency2',CF2(ii+1), ...
        'SampleRate',fs);
    
    [h{ii},f] = freqz(bpfilt{ii}.Coefficients,1,4*8192,fs);
    
end
figure
subplot(211)
plot(f,db(abs([h{:}])));
title('Magnitude')
ylabel('Magnitude (dB)')
xlabel('Frequency (Hz)')
subplot(212);
plot(f,180/pi*(angle([h{:}])));
title('Phase')
ylabel('Phase (degrees)')
xlabel('Frequency (Hz)')
impulse_input = 0*fs;
impulse_input(1) = 1;
for ii = 1:numFilts-1
    [y,zf]=filter(impulse_input,:)
end

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Sulaymon Eshkabilov 2024-1-22

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2072611-use-output-of-a-loop-as-its-input-to-a-filter#answer_1394646

在 MATLAB Online 中打开

This is the code:

close all

fs = 16e3;

numFilts = 32;

filter_number = 10;

%range = [50 8000];

CF1=linspace(50, 8000, numFilts+2) -50;

CF2=linspace(50, 8000, numFilts+2) +50;

for ii = 1:numel(CF1)-2

bpfilt{ii} = designfilt( ...

'bandpassfir', ...

'FilterOrder',20, ...

'CutoffFrequency1',CF1(ii+1), ...

'CutoffFrequency2',CF2(ii+1), ...

'SampleRate',fs);

[h{ii},f] = freqz(bpfilt{ii}.Coefficients,1,4*8192,fs);

end

figure

subplot(211)

plot(f,db(abs([h{:}])));

title('Magnitude')

ylabel('Magnitude (dB)')

xlabel('Frequency (Hz)')

subplot(212);

plot(f,180/pi*(angle([h{:}])));

title('Phase')

ylabel('Phase (degrees)')

xlabel('Frequency (Hz)')

impulse_input = 0*fs;

impulse_input(1) = 1;

%%

% Reference signal with some white noise to benchmarch the created filter performances

t = linspace(0,2*pi,200);

rng(13) % Make it repeatable

x = sin(t) + 0.25*rand(size(t)); % Ref Signal with a noise

% Simulation of 1-D digital filter: x_filtered = filter(b, a, x);

a = 1;

figure

hold on

CoLoR = rand(numel(bpfilt), 3);

for ii = 1:numel(bpfilt)

[x_filtered(ii,:),zf(:,ii)]=filter(bpfilt{1, ii}.Coefficients, a, x);

plot(t,x_filtered(ii,:), 'LineWidth', 1.25, 'Color', CoLoR(ii,:))

LEGs{ii} = ['Filter # ' num2str(ii)];

legend(LEGs{:})

end

plot(t, x, 'k-', 'LineWidth', 2, 'DisplayName', 'Data')

xlabel('t')

ylabel('x(t) & x_{filtered} (t)')

grid on

legend('Show')

fprintf('Number of generated filters: %d \n', numel(bpfilt))

Number of generated filters: 32

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

S 2024-1-22

Thank you!

请先登录，再进行评论。

Answer 2

Sulaymon Eshkabilov 2024-1-22

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2072611-use-output-of-a-loop-as-its-input-to-a-filter#answer_1393956

在 MATLAB Online 中打开

If understood your question correctly, this is what you are trying to simulate, e.g.:

close all

fs = 16e3;

numFilts = 32;

filter_number = 10;

CF1=linspace(50, 8000, 32) -50;

CF2=linspace(50, 8000, 32) +50;

for ii = 1:numel(CF1)-2

bpfilt{ii} = designfilt( ...

'bandpassfir', ...

'FilterOrder',20, ...

'CutoffFrequency1',CF1(ii+1), ...

'CutoffFrequency2',CF2(ii+1), ...

'SampleRate',fs);

[h{ii},f] = freqz(bpfilt{ii}.Coefficients,1,4*8192,fs);

end

figure

subplot(211)

plot(f,db(abs([h{:}])));

title('Magnitude')

ylabel('Magnitude (dB)')

xlabel('Frequency (Hz)')

subplot(212);

plot(f,180/pi*(angle([h{:}])));

title('Phase')

ylabel('Phase (degrees)')

xlabel('Frequency (Hz)')

impulse_input = 0*fs;

impulse_input(1) = 1;

%%

% Create a reference signal with some white noise to benchmark the created filter performances

t = linspace(0,2*pi,200);

rng(13) % Make it repeatable

x = sin(t) + 0.25*rand(size(t)); % Ref Signal with a noise

% Simulation of 1-D digital filter: x_filtered = filter(b, a, x);

a = 1;

figure % Visualize Filter performances:

hold on

CoLoR = rand(numel(bpfilt), 3);

for ii = 1:numel(bpfilt)

[x_filtered(ii,:),zf(:,ii)]=filter(bpfilt{1, ii}.Coefficients, a, x);

plot(t,x_filtered(ii,:), 'LineWidth', 1.25, 'Color', CoLoR(ii,:))

LEGs{ii} = ['Filter # ' num2str(ii)];

legend(LEGs{:})

end

plot(t, x, 'k-', 'LineWidth', 2, 'DisplayName', 'Data')

xlabel('t')

ylabel('x(t) & x_{filtered} (t)')

grid on

legend('Show')

11 个评论
显示 9更早的评论隐藏 9更早的评论

Sulaymon Eshkabilov 2024-1-22

在 MATLAB Online 中打开

Here is the correct code to generate 32 filters.

close all

fs = 16e3;

numFilts = 32;

filter_number = 10;

%range = [50 8000];

CF1=linspace(50, 8000, numFilts+2) -50;

CF2=linspace(50, 8000, numFilts+2) +50;

for ii = 1:numel(CF1)-2

bpfilt{ii} = designfilt( ...

'bandpassfir', ...

'FilterOrder',20, ...

'CutoffFrequency1',CF1(ii+1), ...

'CutoffFrequency2',CF2(ii+1), ...

'SampleRate',fs);

[h{ii},f] = freqz(bpfilt{ii}.Coefficients,1,4*8192,fs);

end

figure

subplot(211)

plot(f,db(abs([h{:}])));

title('Magnitude')

ylabel('Magnitude (dB)')

xlabel('Frequency (Hz)')

subplot(212);

plot(f,180/pi*(angle([h{:}])));

title('Phase')

ylabel('Phase (degrees)')

xlabel('Frequency (Hz)')

impulse_input = 0*fs;

impulse_input(1) = 1;

%%

% Reference signal with some white noise to benchmarch the created filter performances

t = linspace(0,2*pi,200);

rng(13) % Make it repeatable

x = sin(t) + 0.25*rand(size(t)); % Ref Signal with a noise

% Simulation of 1-D digital filter: x_filtered = filter(b, a, x);

a = 1;

figure

hold on

CoLoR = rand(numel(bpfilt), 3);

for ii = 1:numel(bpfilt)

[x_filtered(ii,:),zf(:,ii)]=filter(bpfilt{1, ii}.Coefficients, a, x);

plot(t,x_filtered(ii,:), 'LineWidth', 1.25, 'Color', CoLoR(ii,:))

LEGs{ii} = ['Filter # ' num2str(ii)];

legend(LEGs{:})

end

plot(t, x, 'k-', 'LineWidth', 2, 'DisplayName', 'Data')

xlabel('t')

ylabel('x(t) & x_{filtered} (t)')

grid on

legend('Show')

fprintf('Number of generated filters: %d \n', numel(bpfilt))

Number of generated filters: 32

S 2024-1-22

I did! I am still getting 30 for some reason. You only changes after impulse input right?

Sulaymon Eshkabilov 2024-1-22

Just copy and paste my code above and it should give you 32 filters as shown above.

All the best.

请先登录，再进行评论。

Use output of a loop as its input to a filter

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

更多回答（1 个）

11 个评论
显示 9更早的评论隐藏 9更早的评论

另请参阅

类别

标签

Community Treasure Hunt

Use output of a loop as its input to a filter

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

1 个评论 显示 -1更早的评论隐藏 -1更早的评论

更多回答（1 个）

11 个评论 显示 9更早的评论隐藏 9更早的评论

另请参阅

类别

标签

Community Treasure Hunt

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

11 个评论
显示 9更早的评论隐藏 9更早的评论