cannot use element wise operator in frequency response?

Question

SimTec 2022-8-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1785085-cannot-use-element-wise-operator-in-frequency-response

评论： Bruno Luong 2022-8-24

采纳的回答： Abderrahim. B

在 MATLAB Online 中打开

Hi guys,

I am trying to get the requency response of the averaging FIR filter using the element wise operator, code below:

Fs=8e3; % sampling frequency
Fc=170; % cutoff frequency
alpha=1-2*pi*Fc/Fs;
nb=round(log2(1/(1-alpha))); % number of shift to the right correspending to multiplication by alpha
NbPoints=1000;
Ndec=Fs/2/1000;
Fstart=1;
i=1:Ndec*NbPoints;
freq=Fstart*10.^(i/NbPoints);
H_f=(1-alpha)*cos(pi.*freq/Fs)/sqrt(1+(alpha^2)-2*alpha*cos(2*pi.*freq/Fs));
semilogx(freq,20*log10(abs(H_f)))

the problem the H_f provides me only one output and not the vector result. how can I fix this.

3 个评论
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SimTec 2022-8-24

my bad. I just corrected it.. I still do not get the value of the H_f as a vector

Bruno Luong 2022-8-24

The division "/" before sqrt is NOT elemetwise division "./".

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Answer 1

Abderrahim. B 2022-8-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1785085-cannot-use-element-wise-operator-in-frequency-response#answer_1032200

在 MATLAB Online 中打开

Fs=8e3; % sampling frequency

Fc=170; % cutoff frequency

alpha=1-2*pi*Fc/Fs;

nb=round(log2(1/(1-alpha))); % number of shift to the right correspending to multiplication by alpha

NbPoints=1000;

Ndec=Fs/2/1000;

Fstart=1;

i=1:Ndec*NbPoints;

freq=Fstart*10.^(i/NbPoints)

freq = 1×4000

1.0023 1.0046 1.0069 1.0093 1.0116 1.0139 1.0162 1.0186 1.0209 1.0233 1.0257 1.0280 1.0304 1.0328 1.0351 1.0375 1.0399 1.0423 1.0447 1.0471 1.0495 1.0520 1.0544 1.0568 1.0593 1.0617 1.0641 1.0666 1.0691 1.0715

H_f=(1-alpha)*cos(pi.*freq/Fs)./sqrt(1+(alpha^2)-2*alpha*cos(2*pi.*freq/Fs))

H_f = 1×4000

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 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

semilogx(freq,20*log10(abs(H_f)))