Question

需要帮助，因为有点丢失。我试图绘制下面的代码，我在其中制作了白噪声并使用STFT进行带通滤波，但现在我需要将信号绘制成每个通道的两个图形。结果应该是图表。对于图1a。，水平轴应为频率，垂直轴应为幅度。对于（2）.b，横轴应为时间，纵轴应为频率，并使用颜色表示幅度。

function newwhitenoise()
L = 5000; %Sample length for the random signal
Pause = 10000; %Sample Pause Gap
mu = 0;
sigma = 2;

%Need to see left signal is not displaying
Left_signal = sigma*randn(L,1) + mu;
Right_signal = sigma*randn(L,1) + mu;

Long_signal = [Left_signal zeros(L,1); zeros(Pause,2); zeros(L,1) Right_signal];

%Player Object
soundRecord(Long_signal);


disp([Left_signal zeros(L,1)]);
%sound(Long_signal, Fs);

%Plots subplots in graph
%figure
%subplot(211);
%plot(Left_signal, 'b'); grid on;
%subplot(212);
%plot(Right_signal, 'r'); grid on;
end

function signalplayer(signal)
    %load(signal);
    fs = 44100; %Sample Frequency
    obj = audioplayer(signal,fs);
    play(obj);
end

function soundRecord (signal)
fs = 44100; %Sample Frequency
recObj = audiorecorder(44100, 16, 2);
get(recObj)

%save sound to wave file
%filename = 'location.flac';
audiowrite('input.wav',signal, fs);


if ~exist('inFile')
    inFile = 'input.wav';
end

if ~exist('outFile')
    outFile = 'output.wav';
end

if ~exist('frameWidth')
    frameWidth = 4096;          % size of FFT frame, better be a power of 2
end
frameHop = frameWidth/2;

analWindow = hanning(frameWidth);

[inBuffer, Fs] = wavread(inFile);

x = [inBuffer(:,1); linspace(0, 0, frameWidth)'];                   % use left channel only, zeropad one frame at the end

clear inBuffer;

numSamples = length(x);

numFrames = floor(numSamples/frameHop)-1;

% disp(frameWidth);
% disp(numSamples);
% disp(frameHop);
% disp(numFrames);
% disp(size(analWindow));
% disp(size(transpose(analWindow)));

y = linspace(0, 0, numSamples)';


n = 0;                              % init sample pointer.  unlike MATLAB, i like counting from 0

for frameIndex = 1:numFrames

     xWindowed = x(n+1:n+frameWidth) .* analWindow;     % get and window the input audio frame

     X = fft(fftshift(xWindowed));              % do the FFT

     Y = X;                         % copy the input spectrum to output

                                % do whatever processing to Y that you like

     yWindowed = fftshift(real(ifft(Y)));           % convert back to time domain, toss the imaginary part
 %disp(size(x(1:frameWidth)));
 %disp(size(yWindowed));

     y(n+1:n+frameWidth) = y(n+1:n+frameWidth) + yWindowed;

     n = n + frameHop;
end

wavwrite(y, Fs, 'output.wav');

Answer 1

对于图表1，请尝试pwelch，对于图表2，请尝试spectrogram pwelch基本上是STFT平方幅度的平均值。 spectrogram函数返回信号的STFT，因此它对时域中的信号进行操作使用相同的输入参数调用这两个函数，并且在没有输出的情况下调用时，将结果绘制在当前轴上如果您希望频率轴为图2中的垂直轴（y），请在'yaxis'的调用中使用选项spectrogram。我建议你查看两个函数的文档。

在matlab中绘制短时傅立叶变换（注意窗口大小和步长）

1 个答案: