dlloyd:
Yes, but your code already knows the input frequency, so at 2 Hz, only 1 sample is necessary. 100 Hz in --> 50 samples, 1000 Hz --> 500 samples, etc. So there would always be 2 Hz update in changing the output frequency, giving low jitter throughout the whole range 2 Hz -5 KHz input.
good point, Thanks for the help, I will try that.