在Matlab中编程(如何实时处理) [英] programming in matlab (how to process in real time)

问题描述

我正在尝试在Matlab中制作频谱图， 这是我的代码:

i am trying to make a spectrogram in matlab, here is my code:

% Record your voice for 100 seconds.
recObj = audiorecorder;
disp('Start speaking.')
recordblocking(recObj, 100);

% Store data in double-precision array.
my= getaudiodata(recObj);
figure;
specgram(my,512);

问题是，在我讲话时我希望显示频谱图，所以它应该在我讲话时进行更新.当音频来自麦克风时，如何绘制频谱图?所以我应该能够实时查看频谱图

problem is that while i am speaking i want the spectrogram to be shown, so it should be updating as i speak. How can i plot the spectrogram while the audio is coming from microphone? so i should be able to see spectrogram in real time

我也尝试过

% Record your voice for 100 seconds.
recObj = audiorecorder;
disp('Start speaking.')
a=0;
figure;
while a<60
    recordblocking(recObj, 100);

    % Store data in double-precision array.
    my= getaudiodata(recObj);

    specgram(my,512);
    a=a+1;
end

但是它只会在while循环出现时显示频谱图(因此在运行60次之后)

but it will only display the spectrogram when the while loop fishes (so after running 60 times)

推荐答案

这是一种可能的实现.主要问题是，您忘记在末尾调用 DRAWNOW 每个循环:

Here is one possible implementation. The main problem was that you forget to call DRAWNOW at the end of each loop:

Fs = 8000;                    %# sampling frequency in Hz
T = 1;                        %# length of one interval signal in sec
t = 0:1/Fs:T-1/Fs;            %# time vector
nfft = 2^nextpow2(Fs);        %# n-point DFT
numUniq = ceil((nfft+1)/2);   %# half point
f = (0:numUniq-1)'*Fs/nfft;   %'# frequency vector (one sided)

%# prepare plots
figure
hAx(1) = subplot(211);
hLine(1) = line('XData',t, 'YData',nan(size(t)), 'Color','b', 'Parent',hAx(1));
xlabel('Time (s)'), ylabel('Amplitude')
hAx(2) = subplot(212);
hLine(2) = line('XData',f, 'YData',nan(size(f)), 'Color','b', 'Parent',hAx(2));
xlabel('Frequency (Hz)'), ylabel('Magnitude (dB)')
set(hAx, 'Box','on', 'XGrid','on', 'YGrid','on')
%#specgram(sig, nfft, Fs);

%# prepare audio recording
recObj = audiorecorder(Fs,8,1);

%# Record for 10 intervals of 1sec each
disp('Start speaking...')
for i=1:10
    recordblocking(recObj, T);

    %# get data and compute FFT
    sig = getaudiodata(recObj);
    fftMag = 20*log10( abs(fft(sig,nfft)) );

    %# update plots
    set(hLine(1), 'YData',sig)
    set(hLine(2), 'YData',fftMag(1:numUniq))
    title(hAx(1), num2str(i,'Interval = %d'))
    drawnow                   %# force MATLAB to flush any queued displays
end
disp('Done.')

我只显示每次迭代中的频率分量.如果需要，您应该可以修改它以显示光谱图...

I simply display the frequency components in each iteration. You should be able to modify that to show the spectrogram if you want...

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