[time-nuts] FRK and TS-105A
rk at timing-consultants.com
Tue Jul 6 08:51:22 UTC 2010
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Magnus Danielson
Sent: 06 July 2010 09:41
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] FRK and TS-105A
Could somebody from the top of their head give me the most useful pointers
on FRK rubidiums? I now have one as part of a box, and naturally I want to
stash up on the information.
The rubidium locks nicely, if just patiently sitting there and waiting, and
the designers of the box was nice enough to dedicate a status view to the
rubidium monitoring voltages and lock status.
The box itself is a Ball Efratom TS-105A measurement box, which crunches out
frequency offsets and allan variances for 100 ms, 1 s, 10 s and 100 s
directly on the screen. All under the control of the awsome CPU powers of
The box works, but I am trying to collect info on it.
The box will run in either single mixer or double-mixer mode. It accepts
5 MHz and 10 MHz. Each counter channel receives a signal conditioned input
and 10,00001 MHz from the Rubidium. It hits the mixer after an ECL driver
and is then amplified in LM108 and comparator LM111.
From there will a cascade of TTL chips count it, presumably in the 10 MHz
from the rubidium. For 1 s this gives a resolution of 1E-7/1E6 =
1E-13 which isn't too shabby. The only SMD component seen so far is the cap
sitting directly on the mixers terminals. I have not retraced the card in
detail so far, just looked at it breefly (out of curiosity naturally).
If someone has manuals for the TS-105A I will be happy, TvB has promised to
This box is from 1985, so it is not cutting edge, but it is functional,
direct and a bit fun, so why not. :)
It would be fun if it could crank out the observables directly on serial
port or so...
My beast doesn't have the GPIB interface. It may be a matter of hooking up a
cable, but in that case it is undocumented.
time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
and follow the instructions there.
More information about the time-nuts