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Altera_Forum's avatar
Altera_Forum
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10 years ago

nco v13.0 megacore problem

Hi i need seting-up a nco at 100MHz clock and 10 MHz output sine vawe.

I use nco megacore v13.0, but if i put desired output frequency 10 Mhz

the real output frequency is 1 Mhz.

Why?

Regards, Luca

2 Replies

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

    your accumulator is 2^32 , Fs is 100MHz, tuning word is 42949673 so output F = 100MHz * 42949673/2^32 = 1Mhz

    for 10 Mhz the tuning word should be 10 times larger i.e. 10/100 *2^32 = 429496730

    I don't know why gui is displaying that but your vco should be ok in circuit