Matlab starter code

%% For sinusoidal modeling, additive synthesis, 
%% and noise reduction lab.
clear all;
[x,fs] = wavread('wrenpn1.wav');
x = x/max(abs(x)); sound(x,fs); nx = length(x);

%% ANALYSIS PARAMETERS
frameRate =200;  % Hz
R = floor(fs/frameRate);  
M = 2*R;  % Exact COLA not required
nFrames = floor(nx/M)*2;
N = 2^(1+floor(log2(5*R+1))); % FFT length, zero-padding by 5+

maxPeaks = 1; % Up to this many sinusoidal peaks (pure birdsong)

%% VECTOR VARIABLES DECLARATION
amps = zeros(maxPeaks,nFrames);
freqs = zeros(maxPeaks,nFrames);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% ANALYSIS
%%
w = hanning(M);
for m=1:nFrames
        tt = (m-1)*R+1:(m-1)*R+M; 
        xw = w .* x(tt);
        Xw = fft(xw,N); % window phase inconsequential
        [ampsm,freqsm] = findpeaks(Xw,maxpeaks); % Write this!
        amps(:,m) = ampsm;
        freqs(:,m) = freqsm;
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% SYNTHESIS

y = zeros(1,(nFrames+1)*R);
for m=1:nFrames
        tt = (m-1)*R+1:(m-1)*R+R;  % Write the following too:
        [y(tt),state] = 
          additivesynth(amps(:,m),freqs(:,m),tt,state);
end
% Add a frame of silence to make sure amps ramp down to zero:
tt = nFrames*R+(1:R);
y(tt) = additivesynth(zeros(maxpeaks,1),freqs(:,nFrames),state);
y = y/max(abs(y)); sound(y,fs);

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written by Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and Associate Professor (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA), teaching courses and pursuing research related to signal processing applied to music and audio systems. See http://ccrma.stanford.edu/~jos/ for details.