% STA 293
% Thursday 10/7
%
% SPECTROGRAM of a synthetic signal
% LinChirp (increasing freq) + QuadChirp (decreasing freq).
%
%  WindowFT -- Window Fourier Transform
%   Usage
%     specgm = WindowFT(sig,w,m,Name,titl)
%   Inputs
%     sig      1-d signal
%     w        window half-length, default = n/2
%     m        inter-window spacing, default=1
%     Name     string: 'Rectangle', 'Hanning', 'Hamming',
%              'Gaussian', 'Blackman'; Default is 'Rectangle'
%     titl     Optional Title String Modifier
%   Outputs
%     specgm   Window Fourier Transform of sig, n+1 by n complex matrix
%   Side Effects
%     Image Plot of the Window Fourier Transform
%   Description
%   Algorithm
%      supposes signal is non-periodic, i.e. zero-padded
%   Example
%     sig = ReadSignal('Caruso');
%     sig = sig(1:128);
%     specgm = WindowFT(sig);
%   See Also
%     MakeWindow IWindowFT
%   References
%     Mallat, "A Wavelet Tour in Signal Processing"; 
%             4.2.3 Discrete Windowed Fourier Transform.
%
        close all;
        N = 1024;
        f = MakeSignal('Chirps',N);

% for nice plots
        delta = 1/15;
        unit = (1-3*delta)/3;
        h0 = [delta delta 1-2*delta 2*unit];
        h1 = [delta 2*(unit+delta) 1-2*delta unit];
       
figure;clf;

        axes('position',h1);
                plot(f);
                axis([1 N min(f) max(f)]);
        axes('position',h0);
        window = 50;
        specgm = WindowFT(f,window,1,'Gaussian');
                set(0, 'DefaultAxesFontSize', 12);
                set(0, 'DefaultAxesFontName', 'Times')
 print(gcf,'-deps', 'spectrogram.eps')

%-------------------------------------------------------