fft with cdaq9178 & daqmx

[012user]

I'm using daqmx to for signal acquistion on the cDAQ-9178 system. The FFT performance is slow (the harmonics change slowly, and they're there for a little longer after the signal is switched off). Any ideas to improve? 

[tannerite]

Hi,

How are you performing the FFT? Could you take a screenshot of your program?

Regards

[v124]

please see attached vi. FFT is done for the waveform

[tannerite]

LabVIEW's "Find Examples" also hasnt a good implemeation called FFT and Inverse FFT.vi. To perform an FFT, you must feed it an array. By definition, an FFT cannot be "real time". The delay could be that you are feeding the function a large array each time you perform the transform. You could possibly shorten the array and zero pad the rest. It really depends on your application.

Best,

Tanner

[012user]

reading fewer samples does make fft faster. But then for the application accuracy is required. Therefore fewer samples is not desirable.

[tannerite]

I understand. Have you had a chance to check out some of the resources that v124 or myself has posted? Also, A screenshot would be helpful in determining the root cause of your issue.

Best,

Tanner