matlab中的自相关

Question

我想问如何通过我的手对声波中的每一帧做自相关函数，而不是内置函数，我做了一个代码，我不知道它是对还是错，所以请帮助我也想得到音高周期

[sound,  Fs]= wavread('aa.wav');

subplot(5,1,1);plot (sound);title('The Orignal Wave')
frameSize= 10/10^3;
overlapSize= 5/10^3;

frameSize_samples = round(Fs*frameSize);
overlapSize_samples= round(overlapSize* Fs);

shift = frameSize_samples-overlapSize_samples;

nframes=ceil((length(sound)-frameSize_samples)/shift);

frames = zeros(nframes, frameSize_samples);
for i=1:nframes
      frames(i,:) = sound( ((i-1)*shift+ 1):((i-1)*shift+ frameSize_samples) )';
end

subplot(5,1,2);plot (frames(:));title(' Wave after framing')


w = rectwin(frameSize_samples)';

frames1 = zeros(nframes, frameSize_samples);

 for i=1:nframes
     frames1(i,:)=(frames(i,:).*w);
 end

 %/////////////////////////////////////////////////////////

 % calc energy
 numSamples = length(sound);
 energy = zeros(1,nframes);  
 for frame = 1:nframes   
     energy(frame) = sum(frames1(frame).^2);             %# Calculate frame energy
 end
 subplot(5,1,3);plot (energy(:));title(' Energy')


 % calc autocorrelation


 autocorrelation = zeros(1,nframes);
 for i=1:nframes
     for k = 0:frameSize_samples
         autocorrelation(i,:)= sum(frames(i)*frames(i+k));
     end
 end


 subplot(5,1,4);plot (autocorrelation(:));title(' autocorrelation')

Answer 1

基于方程here。自相关方程看起来很好。但是我被frames搞糊涂了。您将其定义为2-D矩阵，然后对其进行线性索引(frames(i))。

此外，for循环for k=0:frameSize_samples没有做任何事情；您在每次迭代中都分配了相同的变量autocorrelation(i, :)，因此它将被覆盖。