Finding the Bug
The code below is suppose to plot 13 cycles of a sinusoidal wave. However there is a problem with the code. The problem in the following code:
F0 =13; T0 =1/F0; Ts = 0.07; t = 0:Ts:13*T0; x = real(exp(j*(2*pi*F0*t-pi/2))); plot(t,x)
Is that the sample rate Ts is incorrect. In the example Ts is too large and should be less than 1/26 instead. The current sampling rate causes matlab to take points the signal are at distances between the points greater than the half of the period of the waveform. As a result it does not produce the correct plot.