Forum Discussion

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

NCO Frequency modualtion

Hi, I am trying to make a frequency sweeper with an NCO. Can anyone tell me how the modulation input into the NCO works. I want it sweep from 1MHZ to 48MHZ? Thank you in advance.
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

isn't a small phase increment equal to a low frequency and a large phase increment a high frequency...so an up counter is appropriate?

that's right, the sample rate should be more than double of the maximum frequency of 48MHz. sweep is a modulation that increases bandwidth, so extra care has to be taken not to alias. if you do a pretty slow sweep you can get away with no oversampling.