[time-nuts] Best phase detector / mixer for 100MHz?

Magnus Danielson magnus at rubidium.dyndns.org
Fri Nov 23 22:34:18 UTC 2012


Hi Anders,

On 11/23/2012 04:42 PM, Anders Time wrote:
> I have been using an minicircuits mixer as a phase detector for measuring
> low frequency(5-10MHz) and it is usually good enough. But when I want to
> measure 100MHz the sensitivity of the mixer decreases a lot, so when I want
> to measure some really low noise 100MHz(Pascall -178dBc floor with 18dBm
> out) oscillators the sensitivity is not good enough. I read in an old
> article by Walls, Stein et al(Design considerations in state-of-the-art
> signal processing and phase noise measurement system) that one can use two
> diodes in series in the double balanced mixer to increase the sensitivity.
> I tried this with some standard 1n5711 Schottky and the sensitivity is now
> 1V/rad, but is there a easier way to do this? /Anders

Craig Nelson and friends over at NIST had a little different stab at 
mixer which might interest you:
http://tf.boulder.nist.gov/general/pdf/2554.pdf

This was intended for 5 MHz, but I am sure you would enjoy reading about 
it never the less.

Cheers,
Magnus



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