[time-nuts] Couple of questions for Racal 1992 owners

Ed Palmer ed_palmer at sasktel.net
Wed Aug 26 23:22:36 UTC 2009


My 1992 has a similarly ugly reference output - until I terminate it.  
Then it's a fairly nice square wave between 0 and 1 volt.  Rise & fall 
times are in the range of 5 ns.  The manual doesn't state what the wave 
shape is, only that it's > 600 mVp-p into 50 ohms. I have a brochure 
that says "TTL levels giving approx. 1Vp-p into 50 ohms".  My phase 
measurements also have a similar amount of 'noise' to yours.

Which timebase does yours have?  I've got option 4E (similar to 4B).  
Although the timebase appears to be stable, I've noticed that the 
counter drifts about 5e-9 during warmup, even when the oscillator has 
been on standby for many days.  It takes a couple of hours to settle 
down.  Does yours do anything similar?

Ed

John Green wrote:
> Just acquired a used 1992 off eBay. Excellent, almost like new with manual
> and even spare fuses. I noticed that the internal reference's waveform is
> more like a nasty sawtooth than a nice sine wave. Is that normal? Also, when
> I hook my GPSDO through a two way splitter and two different length cables
> and measure phase, I get a +\- 3 LSD ambiguity. Is that about right?
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