SDR question for Phi Pi
BR
Posts: 92
Phil, been thinking about your quest to build a SDR using a Prop. You, Pedward and others have done really neat things to build radio receivers and transmitters using a Prop and it's counters. But in many cases are limited by problems with the jitters, and the noise it induces.
But if I understand correctly, there are situations where the counter output is jitter-free...the catch being that the frequency needs to be an integer multiple of PLL frequency which in turn must be related to Prop clock frequency within certain constraints. That correct? <EDIT: actually I'm pretty sure my statement of requirements to get jitter-free output is not correct, but you get the idea>
If yes it would seem to drastically limit the Prop's usefulness if jitter-free output needed since only a few specific frequencies could be used. Except the prop is a fully static design. So what if you fed the Prop's CLKIN using a VCO? Would that allow the CTRs to be set up in a jitter-free configuration with the output frequency modulated using the VCO rather than modulating in the CTR itself?
But if I understand correctly, there are situations where the counter output is jitter-free...the catch being that the frequency needs to be an integer multiple of PLL frequency which in turn must be related to Prop clock frequency within certain constraints. That correct? <EDIT: actually I'm pretty sure my statement of requirements to get jitter-free output is not correct, but you get the idea>
If yes it would seem to drastically limit the Prop's usefulness if jitter-free output needed since only a few specific frequencies could be used. Except the prop is a fully static design. So what if you fed the Prop's CLKIN using a VCO? Would that allow the CTRs to be set up in a jitter-free configuration with the output frequency modulated using the VCO rather than modulating in the CTR itself?