Forum Discussion

HGAEN's avatar
HGAEN
Icon for New Contributor rankNew Contributor
6 years ago
Solved

Inconsistencies in FFT IP Core and Matlab FFT Output

I'm attempting to simulate a fixed point variable streaming FFT IP core in Matlab, and compare its output to the output of the built-in Matlab fft. The core produces transforms that are similar to th...
  • CheepinC_altera's avatar
    CheepinC_altera
    6 years ago

    Hi,

    Sorry for the delay. I have been performing some tests in Matlab on this. For your information, based on my understanding, Matlab FFT seems to be working with Natural data type only. I have generated a FFT instance with configuration similar to yours but set the Input Order = Natural instead of Digit Reverse. This is to further isolate the part of undoing digit reverse.

    As I simulated the Matlab model using your fft_test.m, it seems like I am able to get similar peak frequency between Matlab FFT and CV FFT. I have sent the simulation zip and the screenshot to you through the Forum email for your reference.

    Note that I am using CV FFT in Q17.0Std and Matlab R2015a since I only have these available in my PC.

    Please let me know if there is any concern. Thank you.

    Best regards,

    Chee Pin

CheepinC_altera's avatar
CheepinC_altera
Icon for Regular Contributor rankRegular Contributor
6 years ago

Hi,

Sorry for the delay. I have been performing some tests in Matlab on this. For your information, based on my understanding, Matlab FFT seems to be working with Natural data type only. I have generated a FFT instance with configuration similar to yours but set the Input Order = Natural instead of Digit Reverse. This is to further isolate the part of undoing digit reverse.

As I simulated the Matlab model using your fft_test.m, it seems like I am able to get similar peak frequency between Matlab FFT and CV FFT. I have sent the simulation zip and the screenshot to you through the Forum email for your reference.

Note that I am using CV FFT in Q17.0Std and Matlab R2015a since I only have these available in my PC.

Please let me know if there is any concern. Thank you.

Best regards,

Chee Pin