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

Charles Steinmetz csteinmetz at yandex.com
Tue Jan 5 21:26:14 EST 2016


Bruce wrote:

>You mean DMTD =  dual mixer time differencenotDDMTD = Digital dual 
>mixer timer difference.The latter uses a pair of synchronisers / 
>shift registers instead of a pair of mixers.

I don't see how your comment is relevant to my post -- I did not 
mention either DMTDs or DDMTDs.  I only noted that the AD835 is 
noisier than a diode mixer, although not as noisy as many analog 
multipliers -- and that some noise improvement has been demonstrated 
by using parallel multipliers.

Charles



>On Wednesday, 6 January 2016 12:03 PM, Charles Steinmetz 
><csteinmetz at yandex.com> wrote:
>
>
>  Poul-Henning 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 ?
>
>You could have mentioned any of dozens of popular analog multipliers,
>and the answer would have been, "because they are way too
>noisy."  The AD835 is also substantially noisier than diode mixers,
>but it at least begins to bridge the gap.  The folks at CERN have
>been improving phase detector S/N by averaging the output of several
>AD835s for the TPMON project, with promising results.  There is a
>preliminary report in "EUROTeV Report 2006-005-1."
>
>See also:
>
>RF-based electron beam timing measurement with sub-10fs resolution,
>A. Andersson and J. P. H. Sladen, CERN (EUROTeV Report 2008-015)
>[phase detector with 8x AD835 analog multipliers].
>
>ANDERSSON, A. and SLADEN, J. P. H.: "First tests of a precision beam
>phase measurement system in CTF3" (Proc. PAC07).
>
>"PRECISION BEAM TIMING MEASUREMENT SYSTEM FOR CLIC SYNCHRONIZATION,"
>A. Andersson, J. P. H. Sladen, CERN (Proceedings of EPAC 2006).
>
>Best regards,
>
>Charles




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