I have an ADF4350 setup to generate 3177.216MHz and 1588.608MHz derived from a 26MHz reference clock and would like to work out the frequency error down to a fraction of a Hz. Assume we have a perfect 26MHz reference clock.
Using the following settings:
input ref clock - 26MHz
pfd freq = 2.6MHz
N counter: 1222
R counter: 10
doubler : 0
BS counter: 21
RF divider: 2
Given these settings how can I calculate back the actual frequency of the VCO output? The frac-n synth has only a finite resolution so the VCO will not be exactly 3177.216MHz. 12bits for the fractional and 12bit modulus. If I plug this in the formula from the datasheet I will get back exactly the frequency I want. The formula though uses floating point numbers though so you won't see the rounding errors.
target RF output freq: 1588608000.000 Hz
Aux output freq: 3177216000.000 Hz
calculated Rf freq: 1588608000.000 Hz