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Altera_Forum's avatar
Altera_Forum
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17 years ago

NCO:Sine Waveform

Hi. I am trying to use the NCO to generate the sine waveform. However, the waveform obtained is different where it is attached. May i know where to modify it in order to get the correct the sine waveform?

FYI, i chose the parellel CORDIC algorithm to generate sine waveform.

Spec:

Phase Acc: 32

Angular Position: 16

Magnitude Precision: 16

Clock rate: 50M

desired freq: 1M

phi_inc_i: 85899346

Thanks

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Looks like you have a sign problem. The NCO output is a signed vector, and I assume that you are displaying it as an unsigned.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    I try to add phase dithering with diff level(min, average and max). However, three look alike. Do u have any experience on it(add phase dithering or other noise)?

    thanks