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– Postscript –
Here is a ‘paper’ method of calculating values for the various latches of the ADF4110. The ADIsimPLL utility does not handle awkward decimal frequencies conveniently although, by rounding them off, loop filter values may be derived quite easily.
Given: Fxtal = [( P x B ) + A ] x Fref / R
If R is made equal to the reference frequency times the oscillator chain multiplier then [( P x B ) + A ] must equal the injection frequency. From there, after arbitrarily choosing P, it is simple arithmetic to work out B and A. As the lower the value of R means the higher the phase-detector reference frequency, and possibly the lower the phase noise, the results may be plugged into the spreadsheet and optimised as described there by dividing it down as far as possible with A still remaining an integer or else equal to zero.
An example calculation:
F = 5760MHz (using 144MHz transceiver)
Finj = 5760 – 144 = 5616MHz
Multiplier = 48
Fxtal = 5616 / 48 = 117.0MHz
Fref = 10MHz
Putting R = 10 x 48 = 480
So then ( P x B ) + A = 5616
Choosing P = 8
B = INT( 5616 / P ) = 702
A = P x FRACT( 5616 / P ) = 0
Finally: [( 8 x 702 ) + 0 ] x 10 / 480 = 117.0 and,
although A = 0, R may still be divided further.
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