Hi team,
my customer is using 2 of the LMX2594s tuned in 1MHz running in fractional and integer mode depending on the tune frequencies.
When they run in fractional mode, to reduce spurious performance, they increase the mod order and pfd delay and see improvement in spurious performance once they get to a 3rd order modulator with a pfd delay of 3.
the issue is now they are seeing a low level noise/spur that is moving through the spectrum of the LO output. it is seemingly periodic and just above the noise floor of the spectrum. have we seen this before and is there a solution? are there methods/best practices to reduce this?
Thanks,
Kevin