function y = synth_AM_noise(f0);
% f0: modulation frequency in Hz
% y=synth_AM_noise	- synthesize amplitude modulated noise


global sr;	% sampling rate


y = synth_noise;
D = size(y, 2) / sr;
x = abscissa(D);

x = 0.5 * (1+cos(x*2*pi*f0));
y = y .* x;