Re: [time-nuts] Microsemi up for sale?

> > rich...@karlquist.com said: > > 2. Magnetic state selection, as used in the 5071A, would be replaced by > > optical pumping. Len Cutler was heartbroken that HP/Agilent management > > wouldn't fund this effort. > > > It turns out that, even now in 2018, optical pumping is not ready for >

Re: [time-nuts] Microsemi up for sale?

Just a change to the last part of the name then ;) https://www.ft.com/content/10192a2a-1d99-11e8-956a-43db76e69936 "semi" -> "chip" On Sat, Jan 27, 2018 at 1:27 AM, Clint Jay wrote: > Perhaps of interest to the list > > https://www.theregister.co.uk/2018/01/25/microsemi/ >

Re: [time-nuts] Phase noise in stable 32

For AllanTools and other testing I have tried the FFT plots in Stable32. It seems to use a fairly simple FFT which has problems for divergent noise-types. The Welch algorithm is better for these. The x-axis should end at the Nyquist frequency, i.e. half of your data rate. For meaningful

Re: [time-nuts] On the IETF leap-seconds.list SHA1

> > > For the Paris Observatory and USNO files my program agrees with the SHA1s > > in the files. > > For the IETF file there seems to be one byte, a "0" at the start of the > > third group of 8 hex characters missing. > >This is not a bug but a « feature ». From the ntpd leap hash checking >

Re: [time-nuts] On the IETF leap-seconds.list SHA1

the future maintenance of 'leapseconds'. > > That is, it's just a copy of NIST's file. > > Your email would make a lot more sense if you had included the URLs > directly rather than referring to your source code and output file that > happen to contain them. > > --jh...@mit.edu > John Hawkinson > > Anders Wallin <anders.e.e.wal...@gmail.com> wrote on Wed, 20 Dec 2017 > at 13:51:21 +0200 in

[time-nuts] On the IETF leap-seconds.list SHA1

Hi all, So I'm doing the typical Wednesday thing you might do, that is writing a small script for checking the SHA1 checksum in leap-seconds.list files. I came up with [1] which produces output [2]. For the Paris Observatory and USNO files my program agrees with the SHA1s in the files. For the

Re: [time-nuts] Favorite counters (current production)?

The CNT-90/91 an 53230 both have graphical presentation, which is very > beneficial. The SR-620 still have better performance even being older than > everything else. > Magnus can you elaborate on the SR-620 performance? In my hands the 53230A with a spec of 20ps single-shot does about 11-13 ps

Re: [time-nuts] Spice simulation of PSRR and phase noise

FWIW I recently took a peek inside a commercial distribution-amplifier and it seems to use two LMH6702 op-amps in parallel. There are two of these dual-LMH6702 stages with a 1:2 splitter after the first, and then a 1:4 splitter after the second stage. 8 outputs in total, with an additional op-amp

Re: [time-nuts] Distribution amplifier (again!) - now mostly ok but has gain peaking

On Sat, Jan 28, 2017 at 5:53 PM, Mattia Rizzi wrote: > Have you tried to use clock distribution components like 5PB1108? You could > use that to distribute the LT1711 output to the output stages > *independently*. You could use also 5PB1108 as output stage as well (but >

[time-nuts] Isolated 1PPS-input for distribution-amp?

Hi all, I'm looking for a solution for galvanic isolation of a 1PPS signal-input to a distribution amplifier. We have an old box using HCPL-2411 at the input followed by 74LS04, but the degraded rise-time (from below 3ns out of a clock, to >12 ns out of the box) and increased jitter (from below

Re: [time-nuts] gLAB PPP noisy clock residuals

> I have not been able to get a copy of the nrcan-ppp softwarepackage, so I > am looking elsewhere. ESA gLAB looks like it might fit the bill. The > problem, in short, is that the data I get from postprocessing with gLAB is > much, _much_ noisier than the results I get from submitting the RINEX

Re: [time-nuts] Measuring coax temperature coefficient with a TICC

The recent supplement to Microwave journal has a piece on phase stability of cables (predictably - written by a vendor of said cables..): http://www.microwavejournal.com/publications/1/editions/223 maybe you can recalculate your results in PPM and plot against temperature, to compare with the

Re: [time-nuts] RFDO - Experience and questions

FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days ago. The signals look like this from our site: http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg

[time-nuts] Distribution amplifier (again!) - now mostly ok but has gain peaking

Hi all, I've been tinkering with another distribution amplifier design and made some measurements earlier this week. The goal is roughly 1:8 fan-out, gain of 0 dB, for good quality (Cs, maser, OCXO) 5 or 10 MHz signals in the range of maybe +0 dBm to +15 dBm - in a 1U form-factor. Earlier I made

Re: [time-nuts] PN/AM and 1.5Hz spur from frequency doubling?

?) Anders On Fri, Jan 20, 2017 at 11:06 AM, Anders Wallin <anders.e.e.wal...@gmail.com > wrote: > Thanks for all the comments so far. > I will try the doubler with another quieter source, and try removing > various potential noise-sources and exchanging cables... > > I have no

Re: [time-nuts] PN/AM and 1.5Hz spur from frequency doubling?

Thanks for all the comments so far. I will try the doubler with another quieter source, and try removing various potential noise-sources and exchanging cables... I have now uploaded a few more images of the same data to the shared album linked in my earlier post. Anders On Thu, Jan 19, 2017 at

[time-nuts] PN/AM and 1.5Hz spur from frequency doubling?

I'm seeing +20-30 dBc/Hz of excess AM/PN, as well as a strong 1.5 Hz spur created by frequency doubling from 5 MHz to 10 MHz. https://goo.gl/photos/GFx9tQoxrSmyzUQo8 The input amplitude to the doubler should be just above the recommended 11 dBm. What's going on?? thanks! Anders

[time-nuts] Measuring sidereal/solar time? Re: A Leap Second is coming

out of curiosity, are there any amateur/semi-pro experiments that can measure the length of the solar or sidereal day to sub-millisecond resolution? To reproduce data like this: https://upload.wikimedia.org/wikipedia/commons/5/5b/Deviation_of_day_length_from_SI_day.svg Something in the sky that

Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

Nice work! On the website in the introduction you mention 22ps single-shot time-stamping on the 5370A/B. I think it's well established that the 53230A does about 11-12 ps for time-intervals, which corresponds to about 9 ps single-channel. see for example:

Re: [time-nuts] Thinking outside the box a super reference

> > > Just for the heck of it, I'd go laser instead of the old UHF lamp. > > > > With respect to precision machining, that space has changed a lot > > over the last five years, with precision CNC machines, factory > > or home-built, dropping dramatically in price. > Yes, the laser technique is

Re: [time-nuts] theoretical Allan Variance question

FWIW this example in AllanTools generates white pm and compares to the IEEE1139 ADEV formula: https://github.com/aewallin/allantools/blob/master/examples/ieee1139_white_pm.py two comments: 1. Theoretical white noise has infinite power, so limiting the RMS to some value already implies you have

Re: [time-nuts] disappearance of NIST UT1 time service

somewhat related: if someone has NTP service distributing TAI, that could be useful for monitoring how the leap second is added to UTC-distributing normal NTP servers come December 31st? might have to set one up myself if there are none in Europe? AW On Thu, Oct 27, 2016 at 1:50 PM, Mike Cook

[time-nuts] Phase-noise through mixer?

Hi group! Can someone help me with how phase-noise through a mixer is calculated? Let's say I connect a 1 GHz signal with -80 dBc/Hz PN (wrt. 1GHz carrier) at some offset to the RF port. I then connect a 900 MHz signal with also -80dBc/Hz PN (wrt. 900MHz carrier) at the same offset. I'm

Re: [time-nuts] Ettus OctoClock measurements

> > > The results are decent but not stellar: > > http://www.anderswallin.net/2016/09/ettus-octoclock- > distribution-amplifier/ > > In particular the AM noise on the 10MHz looks high. Any > thoughts/comments? > > I am not surprised. They used a digital clock distribution chip. The chip > is not

[time-nuts] Ettus OctoClock measurements

Hi all, I measured an Ettus OctoClock with a 3120A phase-noise probe (for the 10MHz) and the 1PPS channel skew with a 53230A TIC. The results are decent but not stellar: http://www.anderswallin.net/2016/09/ettus-octoclock-distribution-amplifier/ In particular the AM noise on the 10MHz looks

Re: [time-nuts] NCOCXO anyone?

> rich...@karlquist.com said: > > Also in 1996, phase microsteppers were already legacy technology and > didn't > > have a good reputation for spectral purity. Another non-panacea. > > What is a phase microstepper and/or how does it compare to a DDS? > > (Google gets lots of hits, but they all

Re: [time-nuts] Quartz Crystal Motional Movement

> Indeed there is an physical limitation for the Q of piezoelectric > resonators, which is given by phonon interactions etc. For quartz this > limit is given approximately by Q*f = 15E12. See attached graph (sorry, in > German). NIce figure! Here's a similar one for MEMS resonators (mostly Si I

Re: [time-nuts] Timelab and the 53220A - getting best results

A time-interval measurement between 1-PPS outputs of your two clocks is the most straightforward to interpret. With the 20ps 53230A I get a noise-floor of about 1.8e-11/tau(s) for this measurement. I haven't tried the 100ps version, I suspect the hardware is identical and HPAK just de-rates the

Re: [time-nuts] Capturing a 1PPS signal with a Keysight 53230A

4. With 1PPS you probably want to run it in time-interval mode and measure the phase difference of two clocks: have it start on CH1 with (say) the 1PPS from your microsemi, and stop on CH2 with your uBlox. You should still have it on ext-REF with 10MHz from the Rb-clock. gate time refers to

[time-nuts] PICDIV build

hi all, I wrote down some notes on a recent PICDIV build and measurements: http://www.anderswallin.net/2016/04/picdiv-frequency-divider/ If/when I make v2 of this board: - any suggestions for boosting the output amplitude of both 1PPS and 10MHz CMOS? Something that drives 3.3Vpp into 50R with

Re: [time-nuts] [Announce] Simulation software for powerlaw noise and PTP clock synchronization

> > I would like to announce the public availabilty of two software projects > which I have been working on for my master thesis: > > * LibPLN: a portable C++ library for the efficient simulation of Powerlaw > Noise (PLN) > Do you get agreement between PLN time-series and calcluated ADEVs, as per

Re: [time-nuts] Unix software to generate nice looking *DEV plots

allantools has functions for most of the xDEV statistics, and it is tested against Stable32 https://github.com/aewallin/allantools or https://pypi.python.org/pypi/AllanTools matplotlib works for plotting, but there are probably many alternatives. Anders On Thu, Mar 17, 2016 at 7:35 PM, Didier

Re: [time-nuts] MV89A / MTI-260 / HP10811 carrier board

Hi, looks quite useful! What's the benefit of the Xilinx CPLD (2-3 dollars/euro) over a PICDIV (<1 dollar/euro) ? Sync-input for the PPS-output would be useful. Also a PPS LED that blinks. If the PPS-divider is directly under the OCXO it will get more or less warm - could that be a problem?

[time-nuts] Distribution Amplifier: a look inside the 6502B

Hi all, I'm continuing with my distribution amplifier project described here: http://www.anderswallin.net/2015/12/frequency-distribution-amplifier-first-tests/ http://www.anderswallin.net/2015/12/frequency-distribution-amplifier-v2-simulations/ The conclusion from those v1 board tests were that

[time-nuts] Distribution amplifier, v2 simulation+design

Hi all, Based on the response to my distribution amplifier prototype I ran a few SPICE simulations with the old AD8055 design and an improved design. The changes are: - better op-amp - improved DC-bias "T" circuit - lower resistance values (esp. gain-setting resistors) results & discussion in my

Re: [time-nuts] SMD TADD-1 distribution amplifier - seeking comments and suggestions?

> > AD8055 in non-inverting circuit with 1+2k7/2k7 gain has 9.6 nV/sqrt(Hz) > > input-referred voltage noise PSD (if I calculated correctly..) > > With +10dBm input the corresponding SSB PN floor should be around > -163dBc/Hz. > HI, How is that calculated? I only get this far: 9.6nV/sqrt(Hz)

Re: [time-nuts] SMD TADD-1 distribution amplifier - seeking comments and suggestions?

e, > > current roll back supply that is controlled by a timer that charges > > the cell every time power is restored, and several times a year if > > power doesn't fail. > > > > Discharge must be abruptly stopped when the cell voltage drops below > > around

Re: [time-nuts] SMD TADD-1 distribution amplifier - seeking comments and suggestions?

nough with an LM329 reference.A damped LCR filter at the input will > improve the PSRR at switchmode output frequencies. > > Bruce > > > > On Tuesday, 1 December 2015 9:02 AM, Anders Wallin < > anders.e.e.wal...@gmail.com> wrote: > > > HI all, > I

Re: [time-nuts] Phase noise from Allan Deviation ?

>From PN to ADEV you integrate under the PN-curve with a certain weighting-function. This paper shows the weighting function: https://www.researchgate.net/publication/6308454_Considerations_on_the_measurement_of_the_stability_of_oscillators_with_frequency_counters to go the other way around you

Re: [time-nuts] Data collection from 5115A phase noise test set?

Thanks for these useful comments! It seems there is no way to estimate frequency from looking at the phase data then? Does TimeLab have automated collection for the frequency-counter data on the control port? Anders On Fri, Dec 11, 2015 at 2:51 AM, John Miles wrote: > > Hi

[time-nuts] Data collection from 5115A phase noise test set?

Hi all, A 5115A phase noise test set landed in our lab and I am wondering about the data collection. It has two telnet ports one for commands and one for phase data. When issuing "start" on the command-port it starts spitting out phase-difference values on the data port. However it seems to me

Re: [time-nuts] Phase microstepper designs?

Do you mean delay-generators for 1PPS? Or a finely-tunable frequency synthesizer? For 1PPS, the fine-delay FMC card might be worth a look: http://www.ohwr.org/projects/fmc-delay-1ns-8cha/wiki afaik it works by first time-stamping the input pulse, then delaying the output with an integer number

[time-nuts] SMD TADD-1 distribution amplifier - seeking comments and suggestions?

HI all, I need to build a few distribution amplifiers (>90% for 10MHz, sometimes maybe 5MHz) and instead of reinventing the wheel I decided to try to modernize the TADD-1 into an all (almost) SMD design. Here are some draft sketches:

Re: [time-nuts] SRS FS710 spurs at 50Hz and harmonics?

en that happens the ripple > goes > way up. A quick check with a scope should tell you what’s happened. 50 Hz > triangle > wave = blown diode. 100 Hz triangle wave = blown cap. > > Bob > > > On Oct 1, 2015, at 4:04 AM, Esa Heikkinen <tn1...@nic.fi> wrote: > > &g

[time-nuts] SRS FS710 spurs at 50Hz and harmonics?

I seem to get very strong spurs at 50Hz and harmonics with an old second-hand SRS FS710: http://www.anderswallin.net/2015/09/srs-fs710-noise-measurement/ feature or bug? Anyone looked at the powersupply and figured out what parts to change? Anders (going crazy measuring all things in sight with

Re: [time-nuts] Symmetricom experts?

FWIW our SyncServer S250 has a PSU with an electrolytic cap that has failed at least twice over the years: http://www.anderswallin.net/2015/08/psu-electrolytic-cap-fix/ Anders On Thu, Sep 24, 2015 at 10:21 AM, G1FEF wrote: > Do we have any Symmetricom experts on this list? >

Re: [time-nuts] measuring os latency for pps

Back in 2012 while playing with LinuxCNC, a program for real-time control of CNC machines, I made a few graphs on the real-time vs. normal kernel performance: http://www.anderswallin.net/?s=latency These are purely software generated and measured events (i.e. we set a thread to run at 1 ms

[time-nuts] monitoring NTP servers?

Hi all, Is there a ready made set of scripts for monitoring a bunch of NTP servers? Preferably for generic unix/linux like ubuntu. I imagine it would look something like: 1. measure data with a test machine, either use output of ntpq -p or perhaps python and ntplib. Variable measurement interval,

Re: [time-nuts] 53230A noise floor

I finally had time to compare the 53230A CONT (resolution-enhanced, aka lambda-counting) and RCON (undocumented! reciprocal continuous counting, aka pi-counting) modes, and wrote down some notes: http://www.anderswallin.net/2015/06/cont-vs-rcon-mode-on-the-53230a-frequency-counter/ comments on my

Re: [time-nuts] Nature: Hyper-precise atomic clocks face off to redefine time

Here are some details on the gravity measurements: http://projects.npl.co.uk/itoc/project-structure/reg/gravity-observations/ AFAIK this campaign is done with GPS-PPP and TWSTFT for frequency comparison. The troposphere makes it hard to reach 1e-17 level for the satellite links - even with a week

[time-nuts] 53230A noise floor

Hi all, I ran some tests on a new 53230A counter that just arrived: http://www.anderswallin.net/2015/04/keysight-53230a-noise-floor-test/ The time-interval single-shot noise and resulting ADEV seems easy enough to explain. I didn't yet have time to look closely at Enrico Rubiola's notes over

Re: [time-nuts] 53230A noise floor

See the part the end that shows why averaging breaks ADEV: http://leapsecond.com/pages/adev-avg/ Hi Tom, thanks for reminding me of that page. I did no averaging of the data myself, and I think it's logical that the counter noise floor goes down with increasing gate time - I just haven't

Re: [time-nuts] Need advice for multilateration setup

What's your budget? Put a white-rabbit switch (3.5keur) in the middle, and install a mile of single-mode fiber to each rx-station. Then use TDC or FDEL SPEC-cards (1.5keur each) at the RX-stations to time-stamp the incoming pulse. 1 ns systematic and 50 ps RMS random error should be doable. The

Re: [time-nuts] Time tagging fpga

Anders, The counter runs on a Pipistrello. I looked at the information on the web about time taggers before starting. I decided to try an oversampling scheme described by a group of Italian? physicists for a multichannel time tagging instrument. They used 4x oversampling. My version is

Re: [time-nuts] Time tagging fpga

On Sat, Nov 22, 2014 at 5:37 AM, Robert Darby bobda...@triad.rr.com wrote: I finally got the time tagging fpga I was playing with to a semi-usable state. I mentioned in an earlier post that I was unable to compile or link the FTDI library but Magnus Karlsson very kindly rewrote a program of

[time-nuts] 53230A input channel fault?

Hi all, I have a 53230A that behaves differently on ch1 and ch2. With ch2 at DC/1Mohm/postive-slope/1V it triggers ok on my PPS signal and shows e.g. a pusle-width measurement etc. The same signal connected to ch1 fails to trigger. I noticed the Vpp and Vmax/Vmin voltage readings are not

Re: [time-nuts] 53230A input channel fault?

A colleague of mine had seen this exact same behavior on another 53230A. The problem is a narrow trace right after the CH1 BNC input. http://www.anderswallin.net/2014/11/53230a-counter-input-channel-fix/ There might be some chemical corrosion going on, since the other counter that experienced

Re: [time-nuts] Measuring ADEV for a beginner

what you want to measure is a time-series of either frequency data or phase data. the simplest possible case for a beginner would be to have two clocks with 1-PPS (one pulse per second) outputs, and connect one clock to the start-input and the other to the stop-input of a time-interval counter. If

Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop

two D-flops in series make a synchronizer!? (see the input-channels on Nutt-type time interval counters) http://chipdesignmag.com/print.php?articleId=32?issueId=5 you've lost all your noise - but you've also got rid of all the signal - so not great for improving SNR. On Tue, Oct 14, 2014 at 6:32

Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop

Interesting 2008 discussion on using a sound-card ADC for a DMTD system! Did anyone build a DMTD-system and measure the performance using a 24-bit soundcard? Does it matter that the ADC in the sound-card is probably clocked by a crystal clock that is 50ppm off and has bad ADEV? Anders On Sun,

Re: [time-nuts] fast switching quiet synthesizer

On Tue, Oct 7, 2014 at 8:32 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Some of the modern DDSes can take 10 MHz directly and step it up internally before hitting the DDS core, but it may be that you need to synthesize a higher clock from the 10 MHz first. We've been

Re: [time-nuts] New TIC test run

Do you have the schematic for this online somewhere? what is the range of the interpolator? which TIC is the red/blue points? the blue data looks like it is aliased somehow, perhaps a number that is truncated/rounded badly? On Sat, Mar 8, 2014 at 9:46 PM, Bob Stewart b...@evoria.net wrote: I

Re: [time-nuts] ADEV from phase or frequency measurement

Here is python code for the most common deviations https://github.com/aewallin/allantools/blob/master/allantools/allantools.py each statistic (ADEV, MDEV, TDEV, and so on) has two functions. one takes fractional frequency data, the other phase data. frequency2phase() and phase2freqeuncy() show

Re: [time-nuts] Sample R script for ADEV under Linux wanted

I recently copy/pasted/googled together this Python library: https://github.com/aewallin/allantools patches, sample datasets, and new tests are welcome! Anders On Mon, Feb 3, 2014 at 2:02 AM, Bob Stewart b...@evoria.net wrote: Subject says it all. Does anyone have a script I could use as a

Re: [time-nuts] high (spacial) precision GPS in Kickstarter

AFAIK 'normal' RTK does not provide a clock solution. There's something called 4D RTK which does: http://saegnss1.curtin.edu.au/Publications/2010/Feng2010Four.pdf apparently the results can be very good - but I think the errors quoted are for time-transfer between two RTK receivers (?). If there

Re: [time-nuts] PICPET- was Affordable (cheap) COTS (etc)

Given that Arduinos are now sold in (almost) every super-market, and the programming IDE is free/open-source, and the C/C++ code is familiar to many, I would have thought the logical evolution of the pictic is to become an Arduino shield? One drawback (AFAIK) is that e.g. Arduino Due doesn't have

Re: [time-nuts] L1/L2 GPS Receiver

Looking at this graph: http://www.thinksrs.com/assets/instr/PRS10/PRS10diag2LG.gif If you have a good PRS10, it only needs adjusting on the many-hours timescale? How much better is a dual-frequency receiver going to be for this, compared to a single frequency receiver? The real benefit of

Re: [time-nuts] sysclock source for AD9912 DDS?

the DDS over 3-wire bit-banged SPI (hardware SPI port is already in use on my arduino). Anders On Mon, Dec 30, 2013 at 5:56 PM, Anders Wallin anders.e.e.wal...@gmail.comwrote: I've tested the AD9912 evaluation board: http://www.anderswallin.net/wp-content/uploads/2013/12/dds_test_2013-12-30

[time-nuts] sysclock source for AD9912 DDS?

I've tested the AD9912 evaluation board: http://www.anderswallin.net/wp-content/uploads/2013/12/dds_test_2013-12-30.png I want to use it with a 10MHz external input clock, but it looks like the on-board PLL that generates a 1200MHz sample clock from my input isn't that great, since I get strong

Re: [time-nuts] sysclock source for AD9912 DDS?

Thanks for all replies so far! It looks like I will play around with the evaluation board some more, and see if I can get the on-chip PLL to behave better. The settings with 2x edge-detector and 60x PLL were the only ones I could find where the output frequency setting in the software

Re: [time-nuts] PPP with RTKLib?

, but the 4ns offset remains. strange. Anders On Fri, Dec 20, 2013 at 2:04 PM, Anders Wallin anders.e.e.wal...@gmail.comwrote: Hi all, I want to use PPP for post-processing of RINEX 2.10 files from a Dicom GTR50/51 GPS receiver. The GTR50 references the time-stamps in the RINEX file to an external

[time-nuts] PPP with RTKLib?

Hi all, I want to use PPP for post-processing of RINEX 2.10 files from a Dicom GTR50/51 GPS receiver. The GTR50 references the time-stamps in the RINEX file to an external PPS input, so this is a way of remotely monitoring a clock. Does anyone know how to run PPP-Static calculations with RTKLib?

Re: [time-nuts] refclock - NTP server settings/tuning?

On Mon, Sep 30, 2013 at 1:17 AM, Hal Murray hmur...@megapathdsl.net wrote: anders.e.e.wal...@gmail.com said: The refclock driver is a userspace C-program (daemon) that essentially does: while(1) { gettimeofday(tv,NULL) // system time, for NTP receiveTimeStamp

Re: [time-nuts] refclock - NTP server settings/tuning?

Thanks for all replies, I can try changing maxpoll to a larger value and see if the trace is smoother. The refclock driver is a userspace C-program (daemon) that essentially does: while(1) { gettimeofday(tv,NULL) // system time, for NTP receiveTimeStamp get_wr_time(wr_tv); // WR time,

Re: [time-nuts] refclock - NTP server settings/tuning?

[1] http://en.wikipedia.org/wiki/White_Rabbit Sorry the correct link is http://en.wikipedia.org/wiki/The_White_Rabbit_Project :) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

[time-nuts] refclock - NTP server settings/tuning?

Hi all, If I have an NTP server with a refclock that is assumed very accurate (~few nanoseconds/day drift at most, with 1 ns jitter), how well should NTP be able to keep the system clock on time? I'm using a White Rabbit (WR) [1] SPEC PCI-card that receives accurate time over WR, and I wrote a

Re: [time-nuts] Generate 1 PPS signal on serial port

On Tue, Aug 6, 2013 at 4:07 PM, Mark C. Stephens ma...@non-stop.com.auwrote: However if you are hell bent on generating PPS in software somehow (please let me know you plan? - curious) FWIW: Over in the hobby-CNC world where it is common to use the parallel port for driving machine tools

[time-nuts] Typical NTP performance? Monitoring multiple NTP servers?

Hi all, I have two NTP-related questions: 1. We are setting up a White-Rabbit[1] network for time-distribution. We 'seed' the WR-network with 10MHz and PPS signals form atomic clocks. This means on each computer in the network there's a very accurate PTP-server running on the WR-card, as well as

Re: [time-nuts] NIST Optical lattice clocks

According to Wikipedia, The optical clock based on it is exact to 17 digits after the decimal point! I hope that doesn't mean it is time to trade my HP 5370B in shortly... How do they measure down to these resolutions? Short answer: instead of a few GHz (Cs clock or H-maser), go to 500 THz or