Diadem FFT script

[DSP_ott]

Hello

I’m trying to do an FFT and a PSD on some acceleration data that varies from amplitude in (g’s) to zero then to an amplitude.

I would like to remove the part when the data goes to zero then to amplitude before I run the FFT.

I currently do it manually using the band cursor in DIAdem. I’m new to the DIAdem and I was wondering if somebody can help.

Thank you,

[James M]

Hi DSP_ott,

You can remove the offending values in your channel by using the CTNV function in the calculator:
Ch("YourChannelName") = Ch("YourChannelName") + CTNV(Ch("YourChannelName") = 0 Or Ch("YourChannelName") = AmplitudeValue)

This will replace all channel values equal to zero or AmplitudeValue with NoValue, which will be ignored when computing the FFT.

For more information about working with NoValue in the calculator, please refer to this KnowledgeBase:
Working with NoValues in the Calculator in DIAdem 10.1

Regards,

Message Edited by James M on 06-05-2007 10:57 AM