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JWall40's avatar
JWall40
Icon for New Contributor rankNew Contributor
5 years ago

No output from FFT IP

I am trying to perform a FFT on a single 1024 sample frame, using streaming architecture. However, I cannot get source_valid to go high or any output. Here's my signal tap 4k samples Start of...
CheepinC_altera's avatar
CheepinC_altera
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi,

Thanks for sharing the QAR. As I look into the design, I understand that you are using Max10 and there is a NCO feeding data to FFT. You are using counters to control the SOP/EOP.

When look into your FFT configuration, I notice the following:

1. Length = 128. If I remember it correctly, you mentioned that you are feeding 1024 samples. Not sure if this is something expected? If not, try setting to 1024.

2. Representation = Block Floating Point. Can you try with Fixed Point.

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

Best regards,

Chee Pin

  • JWall40's avatar
    JWall40
    Icon for New Contributor rankNew Contributor
    5 years ago

    It works!!!! Thank you very much :)

    The length was intentional, I reduced it so I could see more cycles using signal tap without using up all my resources.

    Changing to variable streaming and then fixed point solved the problem. Why does fixed point representation solve the problem? Is it something to do with the Max10 family?

    Many thanks and best regards

    Jack