Tech Note 41 Detail

FFT Not Displaying or Displaying Incorrectly

Affected Products:

CI-6550 NOT A VALID PART NUMBER

Problem/Symptom:
When used in FFT mode, the FFT is either missing or is incorrect. This problem is most evident on old, slow Macs.

PASCO Solution:
  • Reduce the number of points in the FFT (512 or less).
  • Make sure the sample rate is 5-10 times the maximum frequency you hope to see. If you are using a scope to set the rate automatically, make sure you can see 2-4 complete cycles of your signal in the scope trace.
  • Reduce the number of channels sampled.
  • Make sure you are monitoring and NOT recording.
  • Increase the width of the FFT window.
  • If you are on a slow 68K Mac, don't click impatiently; Clicking interrupts the FFT computation.

Creation Date: 01/1/2000
Last Modified: 02/11/2003
Mod Summary: