issues with making a matlab firfilter

Question

Jacob 2023-11-27

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2052332-issues-with-making-a-matlab-firfilter

回答： Chunru 2023-11-27

I am trying to write a matlab code to design a firfilter but I am having trouble getting the filter to work this code below is supposed to determine the frequencies and filter them out of the sunshinesquare.wav file. however when I go to run the program matlab tells me there is an error with the notchfilter line but I can't figure out what is wrong with it any suggestions/help is greatly appreciated.

My code is below

[x, fs] = audioread('SunshineSquare.wav'); 
 
X = fft(x); 
f = linspace(0, fs/2, length(X)/2);
[~, f0] = max(abs(X(1:length(X)/2))); 
 
notchFilter = fdesign.notch('N,Fc', 100, f0, fs); 
b = firpm(notchFilter); 
 
y = filter(b, 1, x); 
sound(x, fs);

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Answer 1

Chunru 2023-11-27

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2052332-issues-with-making-a-matlab-firfilter#answer_1360277

在 MATLAB Online 中打开

%[x, fs] = audioread('SunshineSquare.wav');

load handel.mat

audiowrite("handel.wav", y, Fs);

[x, fs] = audioread('handel.wav');

X = fft(x);

f = linspace(0, fs/2, length(X)/2);

[~, f0] = max(abs(X(1:length(X)/2)));

Warning: Integer operands are required for colon operator when used as index.

f = (f0-1)/fs; % the corresponding freq for index f0

notchFilter_spec = fdesign.notch('N,F0,Q', 100, f, 10, fs/2); %

notchFilter = design(notchFilter_spec, 'Systemobject', true)

notchFilter =

dsp.SOSFilter with properties: Structure: 'Direct form II' CoefficientSource: 'Property' Numerator: [50×3 double] Denominator: [50×3 double] HasScaleValues: true ScaleValues: [1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 … ] (1×51 double) Use get to show all properties

% fvtool(notchFilter)

y = notchFilter(x);

%y = filter(b, 1, x);

% sound(x, fs);

subplot(211); plot(x);

subplot(212); plot(y)