Re: [time-nuts] Designing an embedded precision GPS time server

Hi Nick, I've got a project along those lines that I've been hacking on for the past three years or so, and always meaning to do a thorough writeup on. I'm more of a software than hardware guy, so the heart of it is a Taijiuino Due (a weird Chinese clone of the Arduino Due, so an 84MHz ATSAM3X8E,

Re: [time-nuts] GPS seconds conversion on an Arduino

On Sat, May 13, 2017 at 9:58 PM, Mark Sims wrote: > Converting GPS seconds to Gregorian date/time on the Arduino will be an > arduous task. You take GPS seconds and add it to the GPS starring epoch to > get a Julian date. Then add in the number of leap seconds as a

Re: [time-nuts] Nortel NTGS and LH 5

Looks like it's exactly 1024 weeks off. I'm not sure if it's LH or the receiver doing it, but one of them is convinced that the year 2019 has come and gone. The GPS week number is displayed as 1937 (0x791) but the UTC time displayed is for the same day/date in GPS week 2961 (0xB91). On Thu, Feb

Re: [time-nuts] My TICC came in the mail yesterday

On Fri, Feb 24, 2017 at 7:08 PM, John Ackermann N8UR wrote: > Hi Andrew -- > > There seems to be more than a little magic involved in getting sane > three-corner measurements. I've gotten best results when the run is long > enough to have many data points per tau, and also that

[time-nuts] My TICC came in the mail yesterday

Which means, after a bit of scrounging for some BNC to SMA adapters, I have some plots worth using (more or less) of my clock! Background info: my clock's main purpose is to be a GPS-disciplined NTP server on an Arduino Due clone board. As such, accuracy beyond tens to hundreds of microseconds

Re: [time-nuts] Timelab question

On Tue, Feb 21, 2017 at 5:26 PM, Bob Stewart wrote: > Thanks, John. That will certainly get it to work as I expect it to. I doubt > I'm the only one who's lost a dataset due to being distracted and hitting the > enter key to clear the dialog box. > > Wine is just a mess as

Re: [time-nuts] Survey plot as art.

On Sun, Jan 15, 2017 at 6:23 AM, Andrew Rodland <and...@cleverdomain.org> wrote: > Relatedly, and just for fun, here's a video I made several years ago > from a few days worth of constellation status data out of a cheap SiRF > receiver. It's interesting to see how the satellite g

Re: [time-nuts] Survey plot as art.

On Sat, Jan 7, 2017 at 12:54 PM, Peter Reilley wrote: > > This is the survey from my Trimble NTBW50AA. It looks like some bacteria > floating around. Relatedly, and just for fun, here's a video I made several years ago from a few days worth of constellation status

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

On Wed, Nov 23, 2016 at 10:48 AM, John Ackermann N8UR wrote: > The TICC is implemented as a two-channel timestamping counter. That means > it can measure one or two low-frequency (e.g., pulse-per-second) inputs > against an external 10 MHz reference, or it can do a traditional

Re: [time-nuts] A different way to think about time dilation?

Yes, the math works out. Whether it actually has physical meaning is kind of a philosophical question, but it's a useful tool. https://en.wikipedia.org/wiki/Proper_time#Examples_in_special_relativity is an example worth looking at. On Sun, Jul 10, 2016 at 12:01 PM, Chris Albertson

Re: [time-nuts] Advise on building a DIY GPSDO?

On Sun, Apr 3, 2016 at 6:04 PM, Nicolas Braud-Santoni wrote: > Hi, > > I've been slowly becoming a fellow timenut over the last few years, > though said nuttery had yet to go beyond adding some wiring to > get the PPS signal out of my GPS and into my NTPd. > > >

[time-nuts] Belated leap second video / result

Here's a video of my Spectracom 9183 and my homebuilt GPS/Rb NTP server both cruising through last month's leap second (the first one in my new lab) without incident. Apologies for the blur/bloom on the laptop screen, I guess I didn't get the focus exactly right. You can still read it as long as

Re: [time-nuts] GPS for ntp

On Mon, Oct 20, 2014 at 10:50 PM, Neil Schroeder gign...@gmail.com wrote: The one thing that hasn't yet happened is making the beaglebone timestamp on the linux side in a way that works for ntp. Custom code no problem. Freebsd PPSAPI no problem. Linux, nothing there yet. I have been working

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

Simon, This is a fantastic idea and I have every intention of trying to replicate it at home with tools on hand. Thanks for sharing, and I hope you can show off some results. On Wed, Oct 8, 2014 at 1:09 PM, Simon Marsh subscripti...@burble.com wrote: I've been a lurker on time-nuts for a while,

Re: [time-nuts] Sun Outage

You pick up satellite TV with a parabolic dish that points at one spot in the sky where the geostationary satellite lives. A sun outage happens when the sun wanders into the focus and overloads the receiver with noise that drowns out the satellite signal (at least, it raises the noise floor enough

Re: [time-nuts] First few measurements of my Arduino Due GPSDO

On Thu, Sep 25, 2014 at 3:34 AM, Neil Schroeder gign...@gmail.com wrote: Are all the devices you're using or considering capable of hardware timestamps? Or are you doing it in software today? The PPS from the GPS is timestamped fully in hardware using the input capture function of the hardware

Re: [time-nuts] First few measurements of my Arduino Due GPSDO

? I remember saying after you had taken your last set of pictures that you'd popped it...! On Mon, Sep 15, 2014 at 6:48 AM, Andrew Rodland and...@cleverdomain.org wrote: Neil, I'm working on a blog post now, I'm hoping to have it complete by Monday or Tuesday. I'll send a followup here when

[time-nuts] First few measurements of my Arduino Due GPSDO

Hi all, I've got some figures in from my clock, and I figured I would post them here in hopes of getting some eyes on them and some help with interpretation. Reference is a Spectracom NetClock 9183 with OCXO option. Frequency is good to better than 10^-9, PPS is specified as +/- 50ns.

Re: [time-nuts] First few measurements of my Arduino Due GPSDO

On Sun, Sep 14, 2014 at 4:29 AM, Andrew Rodland and...@cleverdomain.org wrote: My clock is quantized at 10MHz, so you wouldn't expect better than 100ns accuracy. But I added -50ns to the offset in software, making it zero in on the edge where the offset is 0 counts 50% of the time and -1 count

Re: [time-nuts] First few measurements of my Arduino Due GPSDO

your design and build logs/notes. On Sunday, September 14, 2014, Andrew Rodland and...@cleverdomain.org wrote: Hi all, I've got some figures in from my clock, and I figured I would post them here in hopes of getting some eyes on them and some help with interpretation. Reference

Re: [time-nuts] Help understanding an ADEV

Your intuition isn't completely wrong -- the law of averages still applies. As you provide more and more good data it will eventually overwhelm the initial bad data, and the result will get closer to correct. But it will take a *lot* of data to overwhelm even a few data points that have a

Re: [time-nuts] Update on my Arduino GPSDO / NTP server - going atomic

when I get close. Sent from my iPad On Sep 6, 2014, at 10:18 AM, Andrew Rodland and...@cleverdomain.org wrote: Yes, the source is at http://github.com/arodland/Due-GPS-NTP-Server . It should be able to run just fine on the Due part of an Udoo, but you'll have to come up with a different

[time-nuts] Arduino Rb NTP server: good news, bad news, a photo

I've done some more work on the code, mostly in the area of health monitoring -- it's able to look at whether the GPS is locked, whether the Rb is locked, and whether the PLL has a good capture, and decide accordingly whether to enable 1PPS and whether to report a good lock on NTP. It will

Re: [time-nuts] Update on my Arduino GPSDO / NTP server - going atomic

at 1s) that I could use. I have about 100 projects going on but a project like this has been on the back burner for awhile. I have a couple of furies I could test it against also. Bill Sent from my iPad On Sep 5, 2014, at 2:07 PM, Andrew Rodland and...@cleverdomain.org wrote: After some

Re: [time-nuts] Update on my Arduino GPSDO / NTP server - going atomic

On Fri, Sep 5, 2014 at 3:07 PM, Andrew Rodland and...@cleverdomain.org wrote: 1. Should I try using the analog EFC to zero out the amount of correction I ask the X72's DDS for? Could reduce jitter in the timebase, could just add noise. I suppose I can test this one easily enough. Update

Re: [time-nuts] OCXO Voltage Input? (Bob Camp)

On Sat, Sep 6, 2014 at 9:13 PM, Hal Murray hmur...@megapathdsl.net wrote: What's the mechanism for making spurs with a crystal? Get the corners nice and pointy and strap it to a boot. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go

Re: [time-nuts] Update on my Arduino GPSDO / NTP server - going atomic

ticks. 3. Anything else I should consider? If anyone is curious, code is at https://github.com/arodland/Due-GPS-NTP-Server . Thanks for following, Andrew On Tue, Jul 29, 2014 at 12:42 AM, Andrew Rodland and...@cleverdomain.org wrote: Hi all, After a couple years not doing anything except

Re: [time-nuts] Update on my Arduino GPSDO / NTP server - going atomic

Well, my *previous* clock was on the Mega 2560 (an AVR chip, although admittedly one with more code space and IO than usual). I made some mention of it back in 2012. It had 500ns timer granularity and no Rb (just DPLL of a timer running off of the onboard crystal) but it still managed well enough

[time-nuts] Update on my Arduino GPSDO / NTP server - going atomic

Hi all, After a couple years not doing anything except letting it sit in my den and provide time for my home network, I've decided to start hacking on my hobby project again. For reference, what I've got right now is a Freetronics EtherMega (ATMega2560-based Arduino clone with integrated W5100

Re: [time-nuts] zero crossing of venus

Jim Lux jimlux@... writes: On 6/5/12 5:20 PM, Tom Van Baak wrote: Attached are two snapshots of a NASA live feed -- an interesting reminder about the difficulty measuring timing signals with great precision. When you look closely, the leading edge of the sun is rather ill-defined, not

Re: [time-nuts] PICTIC II ready-made?

Hal Murray hmurray@... writes: albertson.chris@... said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some

[time-nuts] PICTIC II ready-made?

I've been having a lot of fun with this time-nut stuff over the past year or so, and I'm thinking about going atomic in the next year (GPSDRbO), but I'm a microprocessor kind of guy, and I have incredibly clumsy hands with electronics and soldering. As much, I'm wondering: Would anyone be willing

Re: [time-nuts] Rigol scopes

lstoskopf@... writes: I bought one of the 50 MHz versions at Dayton last year. OK for my needs. Not mentioned here is that the difference between the 50 and 100 MHz scopes is software control of roll off on the input. I haven't done it, but procedure was available on the WEB on how to

Re: [time-nuts] FPGA GPSDO (Was: Re: NTP jitter with Linux)

Chris Albertson albertson.chris@... writes: On Fri, Apr 6, 2012 at 9:41 PM, Andrew Rodland andrew@... wrote: Another option would be building something on an FPGA. This would be a considerable stretch for me, since I've never done FPGA work, but if I build from the ground up, I can

[time-nuts] FPGA GPSDO (Was: Re: NTP jitter with Linux)

Azelio Boriani azelio.boriani@... writes: On a side note, speaking of deterministic systems, why has no one built a GPSDO with an FPGA yet? Or an NTP server? :) Yes, I have: I have a GPSDO entirely on a 50Kgates FPGA (Spartan3 XC3S50) without microprocessor. GPS is the iLotus M12M and