[time-nuts] Nortel GPSDO osc age alarm

[Bob Camp]

Hi

That’s a cell phone base station board. It’s got a bunch of outputs, some of which are related to the cell network it was built for rather than 10MHz. I’d bet your 9.8 MHz output is one of those. They are DDS based so there likely is some range of possible outputs. 

The age alarm is not unusual on a newly powered up board. It’s moving faster than it should. It may settle down. 

The DAC at limit is not a real good sign ….

Bob

On Jan 23, 2014, at 6:43 PM, Volker Esper <ailer2 at t-online.de> wrote:

> Hi!
> 
> I bought a Trimble/Nortel GPSDO
> 
> http://www.ebay.de/itm/300933951405?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648
> 
> and Lady Heather's now tells me that everything is alright - except
> - DAC 6.000004V
> - OSC BAD
> - osc age alarm
> 
> The rectangle "10MHz" output signal (J5) shows a signal at about 9.8MHz
> (a deviation of about 200kHz), wobbling 4Hz up and down. Oddly enough,
> the direct oscillator output (J4) shows a sine wave at a stable
> 10.0000004MHz (a deviation of 0.4Hz).
> 
> It seems to me it's not the oscillator that is bad but the servo loop -
> what can I do?
> 
> Thank you
> 
> Volker
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