how to graph function
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[y,Fs] = audioread('C:\Users\Casper\Desktop\3.3V.wav');
L=length(y); % series length
;
f = Fs/2*linspace(0,1,L/2+1); % single-sided positive frequency
X = fft(y)/L; % normalized fft
PSD=2*abs(X(1:L/2+1)); % one-sided amplitude spectrum
figure,plot(f,PSD);
grid
xlabel('freq(Hz)')
ylabel('amplitude')
采纳的回答
Star Strider
2021-12-28
Try this —
idx = (f <= 1500) & (f <= 1800)
[rpm, freq] = findpeaks(PSD(idx), f(idx), 'MinPeakHeight',0.75E-3)
Without the data, I cannot experiment with that, however it should return the peak value as ‘rpm’ and the frequency as ‘freq’. If it does not, experiment with 'MinPeakProminence' instead of 'MinPeakHeight' since it cannot be determined from the plot that there are not more components to the desired peak.
.
更多回答（1 个）
Voss
2021-12-28
You could use Data Cursor to create a datatip, or you could try something like this:
idx = find(f(:) > 1000 & f(:) < 2500 & PSD(:) > 0.00075);
3 个评论
burak Kalayoglu
2021-12-28
编辑：burak Kalayoglu
2021-12-28
Voss
2021-12-28
What does this do?
f(1698)
PSD(1698)
burak Kalayoglu
2021-12-28
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