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Mark Sims | 12 Jun 2012 23:48
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NTGS50AA glitches


I saw a similar DAC jump when I replaced the SMB pigtail to my board.   The unit went into a brief holdover and
came out with a shift in the dac vaue.   I would try wiggling the coax connection (without moving the board)
and also gently tapping around the board (maybe start with the oscillator can) with a screwdriver handle
to see if anything causes an upset.
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Dan Rae | 13 Jun 2012 01:19
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Re: NTGS50AA glitches

On 6/12/2012 2:48 PM, Mark Sims wrote:
> I saw a similar DAC jump when I replaced the SMB pigtail to my board.   The unit went into a brief holdover and
came out with a shift in the dac vaue.   I would try wiggling the coax connection (without moving the board)
and also gently tapping around the board (maybe start with the oscillator can) with a screwdriver handle
to see if anything causes an upset.
>
>   		 	   		
>

Interesting.  I just picked it up gently and rotated it through 90 
degrees.  This has produced another 1.5 mV DAC step and corresponding 
temporary jumps in the PPs and Temp traces.

I seem to recall much bigger effects than this when adjusting ovens like 
the 10811 which I always would try to adjust in the orientation that 
they were to be finally used in, so I really shouldn't be surprised.

Dan
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Bob Camp | 13 Jun 2012 02:32
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Re: NTGS50AA glitches

Hi

You are going to get a 5x10^-10 to 2x10^-9 per G frequency shift on most of these oscillator. For anything
below 5x10^-10 a pretty exotic crystal would be needed...

Bob

On Jun 12, 2012, at 7:19 PM, Dan Rae wrote:

> On 6/12/2012 2:48 PM, Mark Sims wrote:
>> I saw a similar DAC jump when I replaced the SMB pigtail to my board.   The unit went into a brief holdover and
came out with a shift in the dac vaue.   I would try wiggling the coax connection (without moving the board)
and also gently tapping around the board (maybe start with the oscillator can) with a screwdriver handle
to see if anything causes an upset.
>> 
>>  		 	   		
>> 
> 
> Interesting.  I just picked it up gently and rotated it through 90 degrees.  This has produced another 1.5 mV
DAC step and corresponding temporary jumps in the PPs and Temp traces.
> 
> I seem to recall much bigger effects than this when adjusting ovens like the 10811 which I always would try
to adjust in the orientation that they were to be finally used in, so I really shouldn't be surprised.
> 
> Dan
> 
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