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Altera_Forum's avatar
Altera_Forum
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17 years ago

NCO 8.1 Problem

HI, no matter what output freq. I set my NCO to have it is always coming out at 20 Mhz, or this is what I am measuring on the scope. I don't think this was happening when i was using quartus 6....
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

I think that your problem is with the phi_inc_i then

This input is responsible for the NCO output frequency

The mega wizard only shows you the value you should set the phi_inc_i, but it doesn't effectively change the frequency

In the thread http://www.alteraforum.com/forum/showthread.php?t=3895 you can find some information on how this works

You must set the phi_inc_i with the value shown on the Phase Increment Value parameter indicated by the wizard to get the desired frequency

I hope this helps you

Regards,

Thiago