zappedagain
Electrical
- Jul 19, 2005
- 1,074
I'm getting an interesting FFT result (see attached diagram) off a pulse that I am digitizing. You can see that I have a lower magnitude alias at 16 KHz. This isn't at 2 times the Nyquist frequency but at about 0.64 times the Nyquist frequency. Why at that frequency?
In our system, we piece the sample data together from a non-linear time delay, and then interpolate it back to fixed time samples before it gets processed through the FFT. I believe I read a few years ago that this type of FFT anomaly is due to distortion in the time samples. I can't find that reference though.
Does anybody have any leads on how to track this issue down? Good books to reference? A name for this phenomenon?
Thanks,
Z
In our system, we piece the sample data together from a non-linear time delay, and then interpolate it back to fixed time samples before it gets processed through the FFT. I believe I read a few years ago that this type of FFT anomaly is due to distortion in the time samples. I can't find that reference though.
Does anybody have any leads on how to track this issue down? Good books to reference? A name for this phenomenon?
Thanks,
Z