find Pitch-synchronous windowing based on pitch tr

问题:

As seen in comment link a pitch by Talkin’s Robust Algorithm for Pitch Tracking in voicebox (function name is "fxrapt") is extracted.

http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/doc/voicebox/fxrapt.html

However, I need to find pitch pulses in the LP error signal by detecting the maximum amplitude within each pitch period. For each pitch pulse, a Hamming window of two pitch periods long. if T(i-1), T(i), T(i+1) denote the locations of three successive pitch pulses. How can I design a analysis window for the pitch pulse at spans from T(i-1) to T(i+1), as illustrated in bellow link Figure ?

I am looking for MATLAB code for it. I will really appreciate, if anyone can help me. Thanks.

回答1:

Steps:

• Apply the pitch track to find the period at each frame, not use overalp in your pitch track, you need do it synchronous and linearly.
• At every time that you find the Period = P search the maximun absolute amplitude on the signal between the range 1 to P*2

these two steps can be done like this:

while ( (k+Step-1) <= Nsamples )

    frame = x(k:k+steps-1);

    P=PITCHTRACK_FUNCTION_HERE

    [v, l] = max(abs(frame(1:P*2)));

   if count == 1

      marks(count) = l;

   else

     marks(count) = l+k-1;

  count = count +1;

  k=k+Step;

end

• you now have all marks referring to your entire signal, then walk around the vector marks to aplly a Hamming window of two pitch periods long !

  test=zeros(length(x),1);
  
  for p=2:length(marks)-2
  
     last=marks(p-1);
  
     next=marks(p+1);
  
  
     test(last:next)=test(last:next) + x(last:next) .*  hamming(length(x(last:next)));
  
  
  
   end
  

PS:

x = your signal

Nsamples = length(x)

k = begins with 1

Step = 256 or 512 or 1024 or 2048