[time-nuts] Re: Symmetricom/Datum FTS-1050A Disciplined Frequency Standard

[Tom Van Baak]

Joe,

Yes, going back many years on time-nuts, two desirable military grade 
vintage portable quartz frequency standards were AN/URQ-10 and 
AN/URQ-23. The latter contained a FE-1050A oscillator which could be 
disciplined by an external reference. The manual goes into great detail. 
[1] See especially pages 2-10, 2-14, 3-2, 3-5, and 5-12.

Right, there is the front panel switch for short (1 s) / long (100 s) 
time constant. In this instrument the integration is analog, not 
digital. The text says it's a 1200 MΩ resistor; although the schematic 
shows 2500 MΩ. Note also the use of a "memory circuit" to maintain 
frequency when the reference input is removed. The manual is wonderful 
old school.

Corby's photos match what's in the PDF. Let it us know if this is the 
same instrument that you remember. I have a URQ 10 and 23 if you have 
more questions. Let us know if your Symmetricom / FTS / Datum 1050A 
looks like a clone of the FE-1050A.

/tvb

[1] ko4bb.com and search manuals for 1050A or URQ23

30,516,123 // 
FrequencyElectronics_ANURQ-23_Frequency_Time_Standard_Service_Manual.pdf


On 4/18/2022 3:18 PM, Joseph Gwinn wrote:
> It has two switch-selectable integration periods, one second and one
> hundred seconds.  I assume that the integration is digital, but in
> hardware versus a computer.
>
> I can provide the documentation, if anybody wants a copy.  Apparently
> a number of folk were looking here, over the years.  Maybe something
> to add to Febo.com.