[time-nuts] Some results of PRS10 and Trimble Resolution

Magnus Danielson cfmd at bredband.net
Thu Jun 29 05:46:26 EDT 2006

From: "Tom Van Baak" <tvb at leapsecond.com>
Subject: Re: [time-nuts] Some results of PRS10 and Trimble Resolution
Date: Wed, 28 Jun 2006 23:01:42 -0700
Message-ID: <004201c69b41$7f5fc480$e412f204 at computer>

> > would you have a schematic of an interpolator with say <5ns resolution  to
> > share?
> Said,
> On interpolators:
> 1) Another good example is found in the op/svc manual
> for the SR620 -- which implements (in simple, non-ASIC,
> 1980's TTL/ECL technology) time interpolators that are
> good to 25 ps. Maybe overkill for you, but the design is
> worth understanding.

Do you happend to have that (and other SR) service manual online somewhere?
I haven't checked their line to closely.

> 2) I recall this recent paper ($) also made good reading:
>     Review of methods for time interval measurements with picosecond
> resolution
>     http://www.iop.org/EJ/article/0026-1394/41/1/004/met4_1_004.pdf

It gives an overview of methods and seems to be in a little deeper on various
forms of gate-based methods.

> 3) Google for words like time interval interpolator and you
> will find quite a lot of sub-ns TIC ideas and products. Few
> seem to be cheap or available, though.

Indeed. It takes a bit of wading through tought.

> 4) The wonderful US patent database also has design
> info on time interpolators (which is good for us home
> time-nuts but perhaps not so good for you if you plan to
> put any of this into your commercial GPSDO product).

There are several paths to finding what you want, one is to search for the
manufactuers name (HP for instance).

> You may in fact find your current 3.33 ns guess is fine.
> Or maybe you'll find that it's not near good enough and
> you are leaving good performance on the table. Let us
> know what you come up with. Perhaps it will shed light
> on why the classic HP GPSDO used a ~100 ps TIC.

BTW, I know it (the Z3801) has interpolators. I just plain forgot for a while.


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