[time-nuts] New 5370A

Bob Stewart bob at evoria.net
Thu May 14 12:39:34 EDT 2015


Hi Magnus,
Would the 5335A have the same sort of clock noise that I'm seeing on the 5370?  I see it when testing on both the 5335A and the 5370A.  I'm setting up a new test as follows:  Internal 5370A clock, PPS from GPSDO to arm input, PRS45A to start input, and a 6 ft piece of RG-58 from start to stop input.  Do you have the same sort of trace on your end when using the internal clock of whatever your test unit is?
Bob

      From: Magnus Danielson <magnus at rubidium.dyndns.org>
 To: time-nuts at febo.com 
Cc: magnus at rubidium.se 
 Sent: Wednesday, May 13, 2015 11:52 PM
 Subject: Re: [time-nuts] New 5370A
   
Hi Bob,

On 05/14/2015 05:11 AM, Bob Stewart wrote:
> I got a new 5370A, so of course I've been running a bunch of tests on it.  In the image linked below, the start channel is my PRS-45A, the stop channel is my GPSDOe ("e" is for engine) and the ARM channel is fed by the PPS from my SSR-6Tru.  As you can see in the notes, the test parameters are all the same, except for the clock source for the 5370A.  As you might guess, my question is about the blue line, which is where the 5370A uses its internal 10811 as its clock reference.  Is it normal for tests run like this to have the left side of the ADEV be such a "wiggle" on the internal reference?  I had noticed the same thing with the 5335A I've been using up till now and had just assumed there was a problem with its 10811.  The OCXO in my GSPDO is a surplus Trimble 34310-T.  It's been running for several weeks, but is still in retrace.
>
> http://evoria.net/AE6RV/5370A/Test1.png

The wiggle indicates that you have some form of disturbance on top of 
your signal. It could be hum, it could be the 5 MHz PWM noise that the 
5370A/B clock buffer board produces. Anyway, that wiggle is typical of a 
noise-source and ADEV isn't always the best tool to find out what it is. 
A FFT would potentially be better for analyzing that issue.

> And kudos to John for Timelab.  It doesn't play well with Wine in Linux, but that's not terribly surprising, all things considered.

Yes, it's a good tool and it's sad that it doesn't play well with Wine 
in Linux. I think John pointed out that Wine did not treat a 
line-drawing call correctly. Anyway, regardless of who is at fault, it's 
sad they don't play well together.

Cheers,
Magnus


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