The 1 PPS signal is derived from an 81 MHz clock (12 ns) on the GPS chip according to the Skytraq manual. So that would mean n * 12ns. ________________________________ From: time-nuts-request@febo.com<mailto:time-nuts-request@febo.com> Sent: ‎3/‎20/‎2017 9:00 AM To: time-nuts@febo.com<mailto:time-nuts@febo.com> Subject: time-nuts Digest, Vol 152, Issue 32 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-request@febo.com You can reach the person managing the list at time-nuts-owner@febo.com When replying, please edit your Subject line so it is more specific than "Re: Contents of time-nuts digest..." Today's Topics: 1. Re: ADEV query Timelab and TICC (Orin Eman) 2. ADEV query Timelab and TICC (Mark Sims) 3. Re: ADEV query Timelab and TICC (GandalfG8@aol.com) 4. Re: ADEV query Timelab and TICC (Dave Martindale) ---------------------------------------------------------------------- Message: 1 Date: Sun, 19 Mar 2017 22:09:57 -0700 From: Orin Eman <orin.eman@gmail.com> To: Tom Van Baak <tvb@leapsecond.com>, Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] ADEV query Timelab and TICC Message-ID: <CAPjY7U9JrUkbfZ=Qy-Wtna9S+=kruW0xyjj8+4LaeGb_B6uOeA@mail.gmail.com> Content-Type: text/plain; charset="utf-8" On Sun, Mar 19, 2017 at 8:03 PM, Tom Van Baak <tvb@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. Orin. [image: Inline image 3]