function y = EXspectrogram(file)
% ### EXspectrogram.m ###         10.27.14
% Reads in wav file created via separate program (e.g., Audacity) and makes a spectrogram
% NOTE: make sure sample rate specified here matches that used when recording the data!

% -------
P.SR= 44100;  % SR data collected at [Hz]
P.windowL= 2048;   % length of window segment for FFT {2048}
P.overlap= 0.8;    % fractional overlap between window, from 0 to 1 {0.8}
P.maxF= 8000;   % max. freq. for spectrogram [Hz] {8000}
fileN= './spectrogram2030.jpg';    % filename to save image to
% -------
pts= round(P.windowL*P.overlap);      % convert fractional overlap to # of points
disp(sprintf('Assumed sample rate = %g kHz', P.SR/1000));
A= wavread(file);
spectrogram(A,blackman(P.windowL),pts,P.windowL,P.SR,'yaxis');  % create spectrogram and plot (via built-in function)
axis([0 size(A,1)/P.SR 0 P.maxF])
colorbar

% -------
% save picture to file as a jpg w/ a user-specified resolution
REZ= '-r180';     % resolution for exporting colormaps to jpg
print('-djpeg',REZ,[fileN]);


% NOTE: to play back the audio, type:
% > sound(A,SR)
% where SR is the appropriate sample rate (e.g., fiddle with if you want to
% change the pitch)

% NOTE: To save an array (A) to .wav file, type:
% > wavwrite(A,SR,16,filename);