view extra/sinemodelpeakint.m @ 10:6840f77b83aa

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function [y]=sinemodelpeakint(x,w,N,t)
%initializing values
M = length(w); % window size - the longer the more frequency resolution
N2 = N/2+1; % positive part of the spectrum
Ns= 1024; % FFT size for synthesis (even)
H = 256; % analysis/synthesishop size
soundlength = length(x); % length of input sound array - samples

fftbuffer = zeros(N,1); % initialize buffer for FFT

%Create a loop to step through the sound array x
%initializing the loop
hNs = Ns/2; % half synthesis window size
hM = (M-1)/2; % half analysis window size used to overlap windows

pin = max(H+1,1+hM); % initialize sound pointer to middle of analysis window
pend = soundlength-max(H,hM); % last sample to start a frame

y = zeros(soundlength,1); % initialize output array
w = w/sum(w); % normalize analysis window
sw = zeros(Ns,1);
ow = triang(2*H-1); % overlapping window
ovidx = Ns/2+1-H+1:Ns/2+H; % overlap indexes
sw(ovidx) = ow(1:2*H-1);
bh = blackmanharris(Ns); % synthesis window
bh = bh ./ sum(bh); % normalize synthesis window
sw(ovidx) = sw(ovidx) ./ bh(ovidx);

while pin<pend
    xw = x(pin-hM:pin+hM).*w(1:M)'; % window the input sound - STFT definition
  
    %zero phased window
    fftbuffer(:) = 0; % reset buffer
    fftbuffer(1:(M+1)/2) = xw((M+1)/2:M); % zero-phase fftbuffer
    fftbuffer(N-(M-1)/2+1:N) = xw(1:(M-1)/2);

    %compute FFT of the zero phased frame
    X = fft(fftbuffer);

    %calculate  magnitude and phase spectrum of of positive frequencies
    mX = 20*log10(abs(X(1:N2)));
    pX = unwrap(angle(X(1:N2)));
    
        
    %Find the locations, ploc, of the local maxima above a given 
    %threshold, t, in each magnitude spectrum by finding changes of slope.
    ploc = 1+find((mX(2:N2-1)>t).*(mX(2:N2-1)>mX(3:N2)).*(mX(2:N2-1)>mX(1:N2-2)));
    
    %Find the magnitudes, pmag, and phases, pphase, of the obtained
    %locations.
    pmag = mX(ploc);
    %pmag = mX(ploc)*0.4; 
    pphase = pX(ploc); 
    
    
    %peak interpolation
    [iploc, ipmag, ipphase] = peakinterp (mX, pX, ploc);
    
    
% plotting the peak values on top of the magnitude and phase spectra at the
% magnitude and phase frame
  
subplot(211); 
plot(mX);
hold on
plot(ploc,pmag,'m*');   %m is for magenta color
plot(nploc,npmag,'c*'); %plot the new magnitude spectra
title('magnitude and peak values');
hold off
subplot(212);
plot(pX);
hold on
plot(ploc,pphase,'m*');
plot(nploc,npphase,'c*');
title('phase and peak values');
hold off
pause