Phase angle in FFT

[CG]

How is Phase angle calculated while conducting FFT in D plot? I was trying to verify D plot by conducting FFT of a single rectangular pulse with very small pulse widths (in order of micro seconds). I seem to get the phase angle wrong using D plot and it appears to be very sensitive to what extent I cut off the x co-ordinates after the pulse signal. I purchased D plot only a week ago and don;t know all the tricks.

I would appreciate if somebody could respond to this as soon as possible. Thanks in advance.

[DPlotAdmin]

The FFT routine returns an array of complex numbers; the FFT is the magnitude of those complex numbers (square root of the sum of the squares of the real and imaginery parts) and the phase angle is the arctangent of the imaginery part/real part.

I don't have that much practical experience working with phase angle but if you have an example that's producing unexpected results, you're welcome to send it to me and I'll look into it.