I revisited this problem yesterday and have it *almost* completely
resolved. By running the synthesizer programming formulas in parallel, I
am able to determine the actual tuned frequency as a function of a
requested frequency and adjust my software local oscillator to compensate.
The synthesizers
Phil,
Unfortunately the answer is rather complicated because there are two
frequency synthesizers involved, not just one. The code that handles
tuning in the firmware is set_freq() here:
https://github.com/mossmann/hackrf/blob/master/firmware/common/tuning.c#L57
To determine the exact frequency
I would like to determine the *exact* frequency of the HackRF when set
to a given frequency. Like nearly all modern tuners they use
"fractional-N" synthesis. They can only tune to frequency steps that are
often not a simple fraction of 1 Hz, and this step size often varies
with operating band.
I'd
