# Time-Frequency analysis using WAV file

조회 수: 77(최근 30일)
Venkata Naga Rohith Tinnanuru 2020년 5월 26일
댓글: Walter Roberson 2021년 9월 4일
Hello Team,
As a part of project I need to plot frequency- time plot of WAV file. Anyway I have figured out plotting the graph using some external code (Examples) and now I have a issue how do I get the plot in milliseconds as time on x-axis since my wav file is of 60 seconds and I have to do deep analysis of graph by give limits to time and clear graph. Here I attach the code that i'm using and the graphs..
clear, clc, close all
x = x(:, 1);
xlen = length(x);
t = (0:length(x)-1)/fs;
plot(t*1E+3, x);
wlen = 1024;
nfft = 4*wlen;
hop = wlen/4;
TimeRes = wlen/fs;
FreqRes = 2*fs/wlen;
TimeResGrid = hop/fs;
FreqResGrid = fs/nfft;
w1 = hanning(wlen, 'periodic');
[~, fS, tS, PSD] = spectrogram(x, w1, wlen-hop, nfft, fs);
Samp = 20*log10(sqrt(PSD.*enbw(w1, fs))*sqrt(2));
w2 = hanning(xlen, 'periodic');
[PS, fX] = periodogram(x, w2, nfft, fs, 'power');
Xamp = 20*log10(sqrt(PS)*sqrt(2));
figure(1)
subplot(3, 3, [2 3])
plot(t, x)
grid on
xlim([0 max(t)])
ylim([-1.1*max(abs(x)) 1.1*max(abs(x))])
set(gca, 'FontName', 'Times New Roman', 'FontSize', 12)
xlabel('Time, s')
ylabel('Amplitude')
title('The signal in the time domain')
subplot(3, 3, [4 7])
plot(fX, Xamp)
grid on
xlim([0 max(fX)])
ylim([min(Xamp)-10 max(Xamp)+10])
view(-90, 90)
set(gca, 'FontName', 'Times New Roman', 'FontSize', 12)
xlabel('Frequency, Hz')
ylabel('Magnitude, dB')
title('Amplitude spectrum of the signal')
subplot(3, 3, [5 6 8 9])
surf(tS, fS, Samp)
axis tight
box on
set(gca, 'FontName', 'Times New Roman', 'FontSize', 12)
xlabel('Time, s')
ylabel('Frequency, Hz')
title('Amplitude spectrogram of the signal')
view(0, 90)
hcol = colorbar('East');
set(hcol, 'FontName', 'Times New Roman', 'FontSize', 12)
ylabel(hcol, 'Magnitude, dB')
disp(['Frequency resolution of the analysis: ' num2str(FreqRes) ' Hz'])
disp(['Time resolution of the analysis: ' num2str(TimeRes) ' s'])
disp(['Resolution of the frequency grid: ' num2str(FreqResGrid) ' Hz'])
disp(['Resolution of the time grid: ' num2str(TimeResGrid) ' s'])
view(-45,65)
colormap bone ##### 댓글 수: 5표시숨기기 이전 댓글 수: 4
Nega Ejjigu 2021년 9월 2일
Can somebody help on to edit the above code so it would accept 2 .wav files then to plot in one graph?
Only I need Amplitude spectrum figure (freq Vs magnitude)

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### 답변(1개)

Nega Ejjigu 2021년 9월 4일
wondering if some one able to rewrite the above code to accept 2 wav files input then two plot just frequency domain in one plot
##### 댓글 수: 1표시숨기기 없음
Walter Roberson 2021년 9월 4일
This is not an Answer to the Question that was asked, and you need to create completely different plots than are used here.

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R2018b

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