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Altera_Forum
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9 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...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 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