Optimizing Power Spectrum Performance

[gcs]

I'm continuously acquiring data from two channels on a PXIe-5122 at a rate of 50 MS/s (100 MS/s total). I would like to compute the power spectral density of each channel while acquiring the data. I'm currently using the FFT Power Spectrum and PSD VI.  I benchmarked the performance of the FFT Power Spectrum and PSD VI on its own and was processing at a rate of about 3 MS/s per channel.

Is there a more efficient VI should I should be using to calculate the PSD?

Is calculating the PSD at these rates even feasible?  If not, any suggestions for alternatives?  (Would an LV FPGA be an option?)

Thanks!

geoff

[Andrew_B]

Hello Geoff,

This is Andrew Brown, an Applications Engineer from National Instruments. The FFT Power Spectrum and PSD VI you mentioned is the recommended method of determining the PSD of data channels. Calculating the PSD given your sampling rates (100 MS/s) would definitely be much faster using the LabVIEW process. However, I was unable to find a specific benchmark.

Some additional resources on using LabVIEW FPGA are located at NI LabVIEW FPGA and in the LabVIEW FPGA Help for FFT. Please let me know if you have related questions on this issue. Thanks, and have a great day!

Regards,

Andrew Brown 

[gcs]

I ended up using LabVIEW FPGA to calcualte the FFTs, power spectra, and cross power specta; accumulate them; and transfer them back to the host.  The host VI handled scaling, display, logging, etc.  This could be done at 50 MHz and worked quite well.  Much, much faster than trying to do it all in software!