% *** plotSOAEwf.m ***       10/27/06

% code to fiddle w/ SOAE time waveform taken using RECsoae.cpp

% specifiable parameters
file='./T4learSOAEwf1.txt';  % SOAE time waveform (assumes SR=22050 Hz)
n=1;       % where to start along waveform (default =1)
N=100;      % # of averages to take (default=60)
nPts=8192; % # of points in FFT buffer (default=8192)
SR=22050;  % sample rate (needed to determine freq. bins)

% -----------------------------------------------
wf=load(file);
time=[0:1/22050:30];
time=time(1:end-1);


for i=1:N
    spec=wf(n:n+nPts-1);
    mag= abs(rfft(spec));
    
    if i==1
        avgMAG= mag/N;
    else
        avgMAG= avgMAG + mag/N;
    end
    n=n+nPts+round(nPts*0.1);  % jump ahead to next section plus a bit xtra  
end

freq=[0:SR/nPts:(SR+1)/2];  % this is likely wrong
plot(freq,db(avgMAG));
axis([0 5000 min(db(avgMAG)) max(db(avgMAG))-5])
grid on;
xlabel('freq. [Hz]')
ylabel('mag. [dB, arbitrary]')
title(['SOAE spectrum taken from averaged segments of time waveform (', file,')'])