[time-nuts] ADEV query Timelab and TICC

Orin Eman orin.eman at gmail.com
Mon Mar 20 01:09:57 EDT 2017

On Sun, Mar 19, 2017 at 8:03 PM, Tom Van Baak <tvb at leapsecond.com> wrote:

> Thanks for the raw data. It's very nice (2 hours 16 minutes = 8219
> points). Everything looks fine with the exception of 8 glitches. These are
> sometimes obvious jumps in phase, which cause massive spikes in frequency.
> Two plots attached.

First, thanks to Tom for taking a look at these files.

> Almost every data point is within a few ns of each other. This is good.
> The standard deviation is a fraction of 1 ns. But once in a while there is
> a relatively massive phase jump. This is bad. Interestingly these 8 phase
> jumps all appear to be about 25 ns or a multiple of 25 ns in magnitude. The
> full list is (ns units):
> 24.575
> 24.724
> 24.831
> 25.047
> 25.087
> 25.549
> 25.589
> 49.623
> 25 * N ns is not random. So I think this is not a Windows problem, not a
> USB problem, not a TimeLab problem, not a TICC problem either.

Personally, I didn't think it was any of the the above either.  The PicDiv
trace showed no such glitches, so I was fairly confident that the TICC was
working well.  But just to verify that, I connected the LTE-Lite PPS to the
5370A and let it run for a few hours.  The 5370A captures similar
glitches.  I have sent the file on to Tom.

For entertainment value, I have attached the current Lady Heather
screenshot for the LTE-Lite.  It has little relationship to the .tim files
I sent to Tom since I generated those a few weeks ago.  FWIW, it shows an
off by two error writing some text, for example: "PDTDT".  This seems to
happen if you go to some other screen (I think it was help in this case)
then returning.


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