[time-nuts] DMTD - analog multiplier vs. diode mixer ?

Magnus Danielson magnus at rubidium.dyndns.org
Tue Jan 5 21:41:16 UTC 2016

With some sine-to-square conversion as signal conditioning, not too hard 
these days, this could be a relatively straight forward approach.
CERN already have digital clocks, so the DDMTD approach fits them well.

For normal mixers you want to signal condition the signal prior to the 
mixers, and then signal-condition the beat notes too.

For DDMTD you do the same, but you do the post mister conditioning in 
the digital domain.

I have always assumed that signal-to-noise have been the main difference 
between the Gilbert cell multiplies vs. diode mixers.


On 01/05/2016 09:19 PM, Bruce Griffiths wrote:
> You could also consider a DDMTD as useed in CERN's White rabbit project.Apart from the sine to logic level conversion its all digital. With care in the design the jitter should be sub picosecond.
> Bruce
>      On Wednesday, 6 January 2016 9:01 AM, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
>   My little HP5065 project is continually running into the jitter of
> my HP5370B counter which is annoying me, so I'm looking int DMTD.
> Everybody seems to be using traditional diode-mixers for DMTD,
> and to be honest I fail to see the attraction.
> Why wouldn't a analog multiplier like AD835 be better idea ?
> What am I overlooking ?

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