[time-nuts] Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input

[Matt Huszagh]

Hi,

I've got a 10 MHz distribution amplifier and am considering purchasing a
5 MHz reference. Most (not all) of my equipment accepts a 5 MHz
reference, but I'd like to be able to use the existing distribution
amplifier I have if possible. Therefore, I'm considering ways I might
generate a low-noise 10 MHz signal from the 5 MHz reference.

An obvious way is to use a doubler. However, as I understand it, even an
ideal doubler will add 20log(2)=6 dB of phase noise to the 10 MHz
signal. It seems like a possibly more expensive, but lower noise way
would be to use a PLL with a divider that locks the divided 10 MHz
signal to the 5 MHz input. If the time constant of the loop filter is
set long enough, does this avoid the phase noise multiplication issue?