[time-nuts] DMTD - analog multiplier vs. diode mixer ?
bruce.griffiths at xtra.co.nz
Tue Jan 5 22:36:57 UTC 2016
On Tuesday, January 05, 2016 09:37:00 PM Poul-Henning Kamp wrote:
> In message <553575724.582265.1452024437677.JavaMail.yahoo at mail.yahoo.com>,
Bruce Griffiths writes:
> >The noise of such Gilbert cell based analog multipliers far exceeds that of
> >the traditional mixer.
> Yes, but does that really matter in this case ?
> The interesting output will be coming out of a LPF so
> most of the noise will die there?/
Yes I believe it does as the mixer multiplier noise sets a lower limit to the
beat frequency jitter.
If only the noise from the 2 mixers were correlated then the jitter
contribution from this would largely cancel out as does the noisee
contribution of the offset oscillator.
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