[time-nuts] Symmetricom SA.35M Information Request

[Magnus Danielson]

Hi Ed,

On 03/16/2016 07:11 AM, Ed Palmer wrote:
> Hi Magnus,
>
> Yes, the 10 MHz output sweeps about +114 and -168 Hz.  The 6.834 GHz is
> moving +84 to -107 KHz.  Not the same ratio, but close enough. So the RF
> side all looks good.  Good thing too since this thing is much too small
> to have any trimmers.  I haven't even found the VCXO.  I think it must
> be on the bottom of the board.

OK, so you sweep over the expected range. Good.

> I got a copy of the Designer's Guide from a kind soul  (Thank you
> again!).  It makes one cryptic mention of a Parameter Recovery mode that
> could result in a 2 hour lock time.  I let it run and logged the
> result.  It tries really hard to get a lock!  It spent 3 hours tweaking
> parameters for the laser trying to get a lock before it gave up.  The
> results look like it might have actually been successful at setting the
> laser parameters so I'm moving on to the detector side.  I haven't found
> the detector yet so I haven't looked for any modulation.  I have to
> reread some documents I found.  I don't think this laser-based unit uses
> the typical modulation scheme.

Never the less, it will be interesting to see if the modulation signal 
makes it through. Exactly what signal it is will be interesting to see, 
but it will be audio-rate.

> I'm doing a lot of reading between the lines and plain-old guessing.
> Lots of fun! :)

Yay! :)
Functioning stuff is so booring, you won't learn from it as if it 
breaks, you need to debug it and figure it out. :)

> I've temporarily set it aside to help a guy try to resurrect an
> FTS-4040A Cesium.  Is that a dead STEL-1173 I smell?  We haven't got to
> that point yet, but it's on my radar!

Haha! That one again. Would be nice to cook up a FPGA replacement for 
it. Should not be too hard, getting the pins match is what will hurt.

Cheers,
Magnus

> Ed
>
> On 2016-03-15 8:02 PM, Magnus Danielson wrote:
>> Ed, On 03/14/2016 10:10 PM, Ed Palmer wrote:
>>> >Does anyone have any info on the Symmetricom SA.35M Miniature Rb
>>> >Standard?  I have the data sheet, patent document and the MACDEMO
>>> >program.  Is there anything else available?  For example, I'd like some
>>> >more explanation of the various parameters read by the MACDEMO program.
>>> >
>>> >I have a sick unit that I'm exploring.  It won't lock.  The VCXO is
>>> >sweeping and I've confirmed the presence of the 6.834 GHz RF signal so
>>> >I'm now looking towards the laser.
>>> >
>>> >I don't expect that I'll be able to get it working, but it's fun to
>>> play
>>> >with.
>> Does the VCXO sweep over the right frequencies. Does it cross 10 MHz?
>>
>> Can you see any status for fundamental and second overtone responses?
>>
>> Can you measure from the detector?
>>
>> Cheers,
>> Magnus
>
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