function y = synth_damp
% y=synth_damp - Synthesize Patterson's "damp" stimulus.

global sr;	% sampling rate
D = 0.1; 	% s - duration
fc = 800;	% Hz - carrier frequency
fe = 40;	% Hz - envelope frequency
half = 4;	% ms - half-life

half = half / 1000;

x = abscissa(D);

% carrier
y = sin(x * pi * 2 * fc);

% envelope
z = mod(x, 1/fe) / half;		% sawtooth, 1 at half-life
z = exp(z * log(0.5));

y = y .* z;