% ### BuildClick.m ###       10.04.13


% code to visually build up a click by successively adding higher and
% higher frequency


clear; clf;

% --------------------------------
% User Inputs

SR= 44100;         % sample rate [Hz]

Npoints= 8192;     % length of fft window (# of points) [should ideally be 2^N]
% [time window will be the same length]



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

dt= 1/SR;  % spacing of time steps

% create a freq. array (for FFT bin labeling)
freq= [0:Npoints/2];
freq= SR*freq./Npoints;

% quantize the freq. (so to have an integral # of cycles)
% [see quantizeF.m for further aspects on this]
df = SR/Npoints;

% create an array of time points, Npoints long
%t= linspace(0,Npoints/SR,Npoints);
t=[0:1/SR:(Npoints-1)/SR];


% click
CLKon= 1000;     % index at which click turns 'on' (starts at 1)
CLKoff= 1001;   % index at which click turns 'off'
clktemp1= zeros(1,Npoints);
clktemp2= ones(1,CLKoff-CLKon);
signal= [clktemp1(1:CLKon-1) clktemp2 clktemp1(CLKoff:end)];




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

% *******
% plot time waveform of signal
if 1==1
    figure(1); clf
    plot(t*1000,signal,'k.-','MarkerSize',5)
    grid on; hold on;
    xlabel('Time [ms]')
    ylabel('Signal')
    title('Time Waveform')
end


% *******
% now plot rfft of the signal

sigSPEC= rfft(signal);

% MAGNITUDE
figure(2); clf;
subplot(211)
plot(freq/1000,db(sigSPEC),'ko-','MarkerSize',3)
hold on; grid on;
ylabel('Magnitude [dB]')
title('Spectrum')
% PHASE
subplot(212)
% radians (wrapped)
%plot(freq,angle(rfft(signal)),'o-','MarkerSize',3)
% cycles (unwrapped)
plot(freq/1000,cycs(sigSPEC),'ko-','MarkerSize',3)
xlabel('Frequency [kHz]')
ylabel('Phase [cycles]')
grid on;
%axis([0 2500 -350 10])



% *******
% now make animation of click getting built up

sum= zeros(1,numel(t));
figure(3); clf;
for nn=1:numel(freq)
    sum= sum+ abs(sigSPEC(nn))*cos(2*pi*freq(nn)*t + angle(sigSPEC(nn)));
    plot(t,sum)
    legend(['Highest freq= ',num2str(freq(nn)/1000),' kHz'])
    pause(0.2)
end