Demos
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n = 64 ` number of points tm = 2 ` max. time in seconds dt = tm/n ` time interval ` the time array t = 0 to tm-dt len n ` the frequency array in Hz (used in the graphs) n2 = n/2 f = (-n2 to n2-1)/tm k = 5 ` signal frequency (Hz) dc = 0.2 ` dc level h1 = dc + sin(2*pi*k*t) ` first signal H1 = abs(ffts(h1)) ` fft with shift h2 = h1 + 0.7*sin(2*pi*(k+3)*t) ` second signal H2 = abs(ffts(h2)) ` fft with shift ` We now modulate the sine by a decaying exponent a = 3 hh = sin(2*pi*k*t)*exp(-a*t) ` modulated signal HH = abs(ffts(hh)) ` fft with shift |