% makes sinusoidal frequency modulation of tone carrier srate = 44100; dur = 1; fc = 1000; % carrier frequency mrate = 4; % modulation rate mindex = 100; % modulation index (for fm = max_freq_change/modulation rate = (fc +/- mindex)/mrate) amp = 0.5; wdms = 10; % window to stop click(need wind.m in same directory) % end of user input t = [ 0 : 1/srate : dur-1/srate ]; y_fc = [2 * pi * fc * t]; y_fm = [-mindex * sin(2 * mrate * pi * t)]; y = amp * sin( y_fc + y_fm); y = wind(srate,wdms,y); wavwrite(y, srate, ['fm_tone.wav']); sound(y,srate) figure plot(t,y); axis([0 dur/2 -1 1]);