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Multi-thread FFT

PostPosted: Thu Oct 03, 2013 9:20 am
by Testman
Multi-thread FFT

I notice that MI's FFT appears to be single-threaded. With the proliferation of multi-core processors, it would seem that MI could greatly benefit from upgrading to a multi-threaded library for FFT. This situation is especially acute for examination of 192kHz 24-bit audio as the highest stable PC that I can hope for will only run at 4GHz stock/5GHz overclocked of which MI will only use one core.

You could charge for multi-threading as a desirable add-on module for MI Pro users.

An advanced option would be to use N-1 cores for FFT to yield back some processor time for other functions at peak utilization.

Post at 11-2-2013 11:43

Thank you very much for the suggestion. We will continue to upgrade the software in terms of both functionality and performance. MI does use multi-threading technique, but the work load may not be balanced among multi-core processors, as you have pointed out.

Post at 19-3-2013 12:09

Re: Multi-thread FFT

PostPosted: Tue Jan 27, 2015 7:36 pm
by usmanali7
I would love to be able to measure wow&flutter of tape machines .basically a known frequency is recorded to the machine, and when played back there is a measure of this frequency, which shows up slow (wow) and fast (flutter) deviations in the speed of the tape transport
a simple multi-meter display of the phase difference between input A and B, useful when aligning the heads on a tape machine.

Re: Multi-thread FFT

PostPosted: Thu Jan 29, 2015 12:26 pm
by VirtinsTech
It can be done using Multi-Instrument Pro. You can define UDDPs (User-defined Derived Data Point) using mathematical expressions. One for frequency difference and the other for phase difference. The peak frequency and its phase in each channel can be obtained by the harmonics function of the spectrum analyzer (refer to Section . They can be accessed through the DDPs: f1Freq_A(Hz), f1Phase_A(D), f1Freq_B(Hz), f1Phase_B(D). Thus, just define two UDDPs as follows: UDDP1: [f1Freq_A(Hz)]-[f1Freq_B(Hz)]; UDDP2: [f1Phase_A(D)-f1Phase_B(D)]

Re: Multi-thread FFT

PostPosted: Mon Sep 18, 2017 1:41 am
by VirtinsTech
Wow and Flutter can now be measured using Multi-Instrument. Please refer to Section of the software manual for detail.

To use the preconfigured Panel Setting File for wow and flutter measurement, go to [Setting]>[Load Panel Setting] and load \psf\pro\UnweightedPeakWowAndFlutter_10s.psf or \psf\pro\WeightedPeakWowAndFlutter_10s.psf for unweighted and weighted wow & flutter measurement.