Re: [time-nuts] GPS receiver time message offsets to 1PPS (updated)

Hi So everything is inside a 10 ms sdev except: UBLOX LEA-6T NMEA at 11.1 ms (Binary is much better) Adafruit Ultimate at 39.8 ms Neither one of those are really surprising. NMEA is not the best thing on uBlox. The specs on the Adafruit part have never made much sense for timing. Somebody was

Re: [time-nuts] Q/noise of Earth as an oscillator

Hi > On Jul 27, 2016, at 12:57 PM, Ron Ott wrote: > > There might be two Qs: one relating to the axil rotation and another > concerning the volume behavior of the earth as a giant bowl of Jello. But > you'd have to figure out how to really slam the planet to excite the

Re: [time-nuts] Q/noise of Earth as an oscillator

Neville Michie wrote: > The conical pendulum has a simple form of a weight on a string, instead > of oscillating in one plane as a conventional pendulum, it swings around > in a circular orbit in the horizontal plane. It has a definite resonant > frequency. I don't think it

Re: [time-nuts] GPS receiver time message offsets to 1PPS (updated)

Yo Mark! On Thu, 28 Jul 2016 02:13:09 + Mark Sims wrote: > I found what was causing the apparent ramps in the message offset > time for the Motorola mode receivers and the Z38xx receivers. And the problem was? RGDS GARY

Re: [time-nuts] Q/noise of Earth as an oscillator

There might be two Qs: one relating to the axil rotation and another concerning the volume behavior of the earth as a giant bowl of Jello.  But you'd have to figure out how to really slam the planet to excite the entire volume. Earthquakes are probably too wimpy. Ron From: Chris Caudle

[time-nuts] GPS receiver time message offsets to 1PPS (updated)

The Skylab is effectively useless for sub-second timing. The message arrival time periodically jumps around, up to +/- 300 msecs. There are a couple of values that it seems to prefer, but any value can be seen. NMEA works a lot better on most receivers that I expected. They send several

[time-nuts] GPS receiver time message offsets to 1PPS (updated)

Lady Heather keeps the date/time time in two sets of variables. One is the receiver time message values in UTC (or GPS) time. The other is local time (UTC/GPS adjusted for time zone or time scale) that is used for the clock displays. There are integer year,month,day, hours,minutes,seconds

Re: [time-nuts] NCOCXO anyone?

On Thu, 28 Jul 2016 14:06:09 -0700 Alex Pummer wrote: > On 7/28/2016 11:03 AM, Attila Kinali wrote: > > On Fri, 22 Jul 2016 08:19:43 + (UTC) > > Bruce Griffiths wrote: > > > >> No, the first one merely uses a pair of cascaded heterodyne PLLs >

[time-nuts] phase noise in digital divider, 2nd harmonic

Hi, Been a while since I visited, I recall there are many, well, time nuts here. I am trying to track down a source of phase noise in a frequency synthesizer design. One part of the frequency reference upconverts a DDS and then divides it down again using a digital divider - standard

[time-nuts] Very Accurate Delta Time RF Pulse Measurements

Hi Guys, This is a little outside of time-nuts scope, but not by much. I'm interested in finding the time between two rising edges above a set threshold with preferably nS or high ps timing accuracy. Can this be simply done with a few programmed Microchip PICs or with a good short term OCXO

Re: [time-nuts] NCOCXO anyone?

if you send the circuit to me Attila, I would try to help you 73 KJ6UHN Alex by the way aside of that ham license, I have some fifty years of experience and also an MSEE On 7/28/2016 11:03 AM, Attila Kinali wrote: On Fri, 22 Jul 2016 08:19:43 + (UTC) Bruce Griffiths

[time-nuts] Histogram of T2 arrival times

http://users.megapathdsl.net/~hmurray/time-nuts/T2-hist.png 24K samples from KS-24361 200K samples from Z3801A The systems collecting the data have 200-300 microsec peak-peak of clock offset, mostly tracking daily temperature swings. A major fraction of the timing difference is explained by

Re: [time-nuts] Q/noise of Earth as an oscillator

Hi All, Tom gave me a nudge to look here - I hadn't been following this thread. For those that don't know, I study pulsars and so the way we measure what pulsars do could be relevant to this discussion. First, I have never heard of a Q measure when referencing a pulsar. I think the key here is

Re: [time-nuts] NCOCXO anyone?

Diophantine Frequency Synthesizer Design for Timekeeping Systems |   | |   | |   |   |   |   |   | | Diophantine Frequency Synthesizer Design for Timekeepi...Abstract Diophantine Frequency Synthesis (DFS), a number-theoretic approach to the design of very high resolution frequency synthesizers,

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

Taking a look for it also turned up a recent time-nuts thread https://www.febo.com/pipermail/time-nuts/2016-May/097801.html On Thursday, 28 July 2016, Scott Stobbe wrote: > There was a pic app note on alternate uses for the cap sense block a while > back, not sure it

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

Hi If you have a need to do < 1 ns with a counter approach, the counter will need to have a GHz clock in it. If you want to use an MCU counter, it will need to have a GHz level clock routed to it. You are unlikely to find an MCU that will do that. An FPGA can get you to 1.25 ns with direct

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

There was a pic app note on alternate uses for the cap sense block a while back, not sure it that it will push you into the ps. On Thursday, 28 July 2016, Jerome Blaha wrote: > Hi Guys, > > This is a little outside of time-nuts scope, but not by much. I'm >

Re: [time-nuts] NCOCXO anyone?

On Fri, 22 Jul 2016 08:19:43 + (UTC) Bruce Griffiths wrote: > No, the first one merely uses a pair of cascaded heterodyne PLLs > as shown on p3 of the manual. Ok. I tried to understand how this circuit works. While I can see how a small and precise frequency