System response from input and output signals
6 次查看(过去 30 天)
显示 更早的评论
My input is chirp signal .How could i get the frequency response of the sysytem from the output . Using this i want to create a database
0 个评论
采纳的回答
Star Strider
2023-8-21
12 个评论
Star Strider
2023-8-25
编辑:Star Strider
2023-8-25
The harmonics are probably there. You will need to increase the system order beyond 32 to get an accurate representation, although modeling all of them may not be possible. (It turns out that tfest models this system better than ssest, so use tfest instead.)
EDIT — (25 Aug 2023 at 14:37)
Another approach (signal processing) is to use the firls function to approximate the transfer function —
Uz1 = unzip('AliELENvarFsin...b500_8_23.zip')
Uz2 = unzip('varFsin_1K.zip')
[inpSig,fs]=audioread(Uz2{1});
size_inp = size(inpSig)
fs
[outSig, Fs] = audioread(Uz1{:});
size_out = size(outSig)
Fs
L = numel(inpSig);
t = linspace(0, L-1, L)/fs;
[FTs1,Fv] = FFT1(inpSig,t);
[FTs2,Fv] = FFT1(outSig,t);
transfcn = FTs2 ./ FTs1;
figure
plot(Fv, mag2db(abs(transfcn)))
grid
xlabel('Frequency (Hz)')
ylabel('Magnitude (dB)')
title('Transfer Function')
n = 350;
f = Fv(1:end-1);
a = abs(transfcn(1:end-1));
b = firls(n, f/max(f), a);
[hz,fz] = freqz(b, 1, 2^16, Fs);
figure
semilogy(f, a, 'DisplayName','Transfer Function')
hold on
plot(fz, abs(hz), 'DisplayName',["FIR Filter (Order "+string(n)+")"])
hold off
grid
legend('Location','best')
function [FTs1,Fv] = FFT1(s,t)
s = s(:);
t = t(:);
L = numel(t);
Fs = 1/mean(diff(t));
Fn = Fs/2;
NFFT = 2^nextpow2(L);
FTs = fft((s - mean(s)).*hann(L), NFFT)/sum(hann(L));
Fv = linspace(0, 1, NFFT/2+1)*Fn;
Iv = 1:numel(Fv);
FTs1 = FTs(Iv);
end
.
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Filter Analysis 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!