Re: [time-nuts] An embedded NTP server
On 1/1/2013 4:58 PM, time-nuts-requ...@febo.com wrote: True story: Many years ago when the very first ARM silicon arrived and they started testing it, it was generally execeeding expectations but a little bit flakey at high clock rates. After the bubbly had been drunk and hangovers subdued, the serious testing started and one of the first thing they found was that they had forgotten to hook up VCC: The chip ran entirely on leaked power from the I/O pins, most notably the #RESET pin. When they also connected the VCC pin, it was stable well above spec'ed speed. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 Ive also seen this, but with a design based on a 8 bit micro running at 50Mhz. Took a while to trace down, because the guy how laid out the board is usually good about power and gnd connections. We found it by putting a volt meter on the VCC pin, and realized it wasn't at 5 volts. (It's surprising how often people don't check VCC voltages on a new layout!) I never figured a 50Mhz proc at ~75mA would run from leakage current into the inputs, but realizing that a lot of I/O have protection diodes, it is probably more common than one would expect. Back on topic (sort of). I've been playing with some of the PIC24 chips lately. They have some neat oscillator options internally, however they seem to have a lot of jitter on I/O compared to other micros that run without a VCO and PLL. Again these PIC's are also designed to be run at low power if necessary. That said, some do have PWM with resolutions down to 1.04nS with special hardware which is impressive. I think it's a DLL locked to ~120Mhz ref clock, locked to an internal RC at ~7.5Mhz. Lots of multiplying going on there! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP 5065A short term stabilities, update
A few years ago I posted the short term stabilities of some HP 5065A. Here is an updated list with some more results. The 1 sec figures with a * indicate a maximum. The actual 1 sec results for those units will be better. The 1340A unit was exceptional! 1 SEC. 10 SEC. 100 SEC. 1K SEC. -- HP 5065A Spec. 5.0-12 1.6-12 5.0-13 5.0-13 -- 940-3.51-12 1.02-12 2.43-13 1.00-13 2432A1.40-12 6.06-13 3.31-13 3.28-14 2340A1.66-12 7.09-13 2.93-13 6.54-14 2640A1.16-12 4.06-13 1.23-13 2.10-14 2816A1 1.04-12 3.89-13 2.40-13 3.37-14 TESTER 1.15-12 7.40-13 3.66-13 7.54-14 RB09 5.50-12 1.00-12 3.00-13 3.00-13 RB02 9.00-13 3.00-13 1.00-13 6.00-14 RB12 2.00-12 4.00-13 1.10-13 5.10-14 TVB2 1.17-12 4.80-13 1.50-13 7.80-14 TVB1 1.13-12 3.32-13 1.13-13 5.10-14 2816A2 *2.62-12 1.09-12 4.12-13 1.10-13 2816A3 1.38-12 5.93-13 2.51-13 7.81-14 1532A 1.8 -12 8.0 -134.0 -13 2432A1 1.4 -12 4.5 -131.6 -13 2816A4 8.0 -13 3.2 -131.1 -13 RB34 *2.10-12 4.5 -131.15-13 2816A5 1.04-12 3.50-13 8.15-14 2816A6 *2.16-12 4.50-13 1.15-13 2740A *2.07-12 4.05-13 1.01-13 1340A9.45-13 3.31-13 9.60-14 2432A2 1.02-12 3.43-13 1.03-13 2432A3*2.01-12 4.11-13 1.25-13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 5065A short term stabilities, update
Corby, Thanks very much for the updated list. I can only imagine how much work that involved over the years. Can you describe your test setup? Also, are you up to testing/repairing more 5065A? I have a few here that I'm not making any progress on. Thanks, /tvb - Original Message - From: cdel...@juno.com To: time-nuts@febo.com Sent: Wednesday, January 02, 2013 8:18 AM Subject: [time-nuts] HP 5065A short term stabilities, update A few years ago I posted the short term stabilities of some HP 5065A. Here is an updated list with some more results. The 1 sec figures with a * indicate a maximum. The actual 1 sec results for those units will be better. The 1340A unit was exceptional! 1 SEC. 10 SEC. 100 SEC. 1K SEC. -- HP 5065A Spec. 5.0-12 1.6-12 5.0-13 5.0-13 -- 940-3.51-12 1.02-12 2.43-13 1.00-13 2432A1.40-12 6.06-13 3.31-13 3.28-14 2340A1.66-12 7.09-13 2.93-13 6.54-14 2640A1.16-12 4.06-13 1.23-13 2.10-14 2816A1 1.04-12 3.89-13 2.40-13 3.37-14 TESTER 1.15-12 7.40-13 3.66-13 7.54-14 RB09 5.50-12 1.00-12 3.00-13 3.00-13 RB02 9.00-13 3.00-13 1.00-13 6.00-14 RB12 2.00-12 4.00-13 1.10-13 5.10-14 TVB2 1.17-12 4.80-13 1.50-13 7.80-14 TVB1 1.13-12 3.32-13 1.13-13 5.10-14 2816A2 *2.62-12 1.09-12 4.12-13 1.10-13 2816A3 1.38-12 5.93-13 2.51-13 7.81-14 1532A 1.8 -12 8.0 -134.0 -13 2432A1 1.4 -12 4.5 -131.6 -13 2816A4 8.0 -13 3.2 -131.1 -13 RB34 *2.10-12 4.5 -131.15-13 2816A5 1.04-12 3.50-13 8.15-14 2816A6 *2.16-12 4.50-13 1.15-13 2740A *2.07-12 4.05-13 1.01-13 1340A9.45-13 3.31-13 9.60-14 2432A2 1.02-12 3.43-13 1.03-13 2432A3*2.01-12 4.11-13 1.25-13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10 MHz - 16 MHz clock multiplier
What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
In message 50e45382.8090...@irtelemetrics.com, Dan Kemppainen writes: Back on topic (sort of). I've been playing with some of the PIC24 chips lately. They have some neat oscillator options internally, I've given up on PIC and Atmel microcontrollers and their antiquated CPU designs. My life is too short to fight odd-ball compilers, when I can get a real 32 bit CPU and a good compiler instead. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
On Wed, Jan 2, 2013 at 11:16 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: I've given up on PIC and Atmel microcontrollers and their antiquated CPU designs. My life is too short to fight odd-ball compilers, when I can get a real 32 bit CPU and a good compiler instead. That is a valid point if you are building a one-off project. Your time is worth something. But if you plan to sell a million AA cell battery chargers using a 32-bit controller is uneconomical. These will always be a bigger market for 8-bit chips then for 32-bit chips. For an NTP server I'd go with something that can run an OS and the NTP reverence implementation. ARM (and others) can do that. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
In message CABbxVHuc1CcVqa2fgY_nriNrT3PYHtP8BSi=5=bsbk9eyhl...@mail.gmail.com , Chris Albertson writes: That is a valid point if you are building a one-off project. Your time is worth something. But if you plan to sell a million AA cell battery chargers using a 32-bit controller is uneconomical. But that's generally not what we discuss here on time-nuts, so I didn't feel I needed to state the obvious... For an NTP server I'd go with something that can run an OS and the NTP reverence implementation. ARM (and others) can do that. Actually, the OS is not important, floating point support is. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 02/01/2013 19:25, Chris Albertson wrote: For an NTP server I'd go with something that can run an OS and the NTP reverence implementation. ARM (and others) can do that. This is exactly what I've done using the Raspberry Pi (Broadcom ARM SOC running Linux) and a GPS module with the PPS kernel hook for Linux GPIO. Still a beginner/aspiring time-nut so I'm not sure on accuracy (PLL offset jitter suggests ~5-10ms worst-case but I've not looked much into measuring it yet), but it's an improvement on internet NTP at least. (Brief writeup here: http://www.talkunafraid.co.uk/2012/12/the-ntpi-accurate-time-with-a-raspberry-pi-and-venus638flpx/ - - be gentle, it's my first 'real' timing project!) James -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) iEYEARECAAYFAlDkjUcACgkQ22kkGnnJQAzbXQCfU6nLKnJ7lPFLGcAZysxaJUuC POsAn3YKaX3IAhk4MbqGnGUNJOSv7oTa =d3dr -END PGP SIGNATURE- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Since injection locking is possible when the ratio of the 2 frequencies involved is a rational number, a 16 MHz oscillator can be directly injection locked to a 10MHz signal without the need for dividers etc. Bruce paul swed wrote: Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baakt...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Bruce is right about that fact. Thanks. Square up the 10 Mhz. Diff the leading edge (It actually doesn't matter) maybe 2-5pf cap and 300 ohm R to ground. Feed this into a transistor that is in the bottom end of a one transistor oscillator. There are actually several ways to inject. Think of a totem pole of 2 transistors. Use google and do a search and you will see what I am talking about. There were some articles that the spread spectrum hams used that describe it. On Wed, Jan 2, 2013 at 2:48 PM, Bruce Griffiths bruce.griffi...@xtra.co.nzwrote: Since injection locking is possible when the ratio of the 2 frequencies involved is a rational number, a 16 MHz oscillator can be directly injection locked to a 10MHz signal without the need for dividers etc. Bruce paul swed wrote: Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baakt...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/**mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Hi I think I'd second the thought of join with an ARM or something like it that will be happy with 10 MHz in. Next choice would be a PIC24 / dsPIC33 that's also happy with 10 MHz in. The money you will pay for the clock conversion chip(s) will go a long way spent on a CPU. Bob On Jan 2, 2013, at 1:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
From: James Harrison [] This is exactly what I've done using the Raspberry Pi (Broadcom ARM SOC running Linux) and a GPS module with the PPS kernel hook for Linux GPIO. Still a beginner/aspiring time-nut so I'm not sure on accuracy (PLL offset jitter suggests ~5-10ms worst-case but I've not looked much into measuring it yet), but it's an improvement on internet NTP at least. (Brief writeup here: http://www.talkunafraid.co.uk/2012/12/the-ntpi-accurate-time-with-a-raspberry-pi-and-venus638flpx/ - - be gentle, it's my first 'real' timing project!) James James, You might be interested in my write-up: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html and its performance: http://www.satsignal.eu/mrtg/performance_ntp.php I was playing with RasPi-1 today to see whether a different (navigation) GPS receiver or system configuration would make any difference to the oscillatory nature of the offset, hence the big step around 11:00 when the card was restarted after an hour's power down. RasPi-2 with a timing GPS receiver looks better, and it should have an identical configuration to RasPi-1 (except that the USB port is being sent data). Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Set up for short term stability tests on HP 5065A
Tom, My setup consists of: NBS 106B DMTD unit that I have upgraded a bit A selected FTS 1200 as an offset oscillator Berts mini counter RS232 interfaced to a laptop for the 1 sec taus without the * the reference is a cherry picked 10811 for the others as well as the higher taus the reference is the EFOS2 Active Hydrogen Maser + the odd cables attenuators etc. I think that's about it! Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
What's the simplest way to generate 16 MHz from 10 MHz? Well, it's a few dollars and *is* a TSSOP, but I've been playing with TI's CDCE913/925/937/949 series. They're nice little I2C-programmable fractional-N PLL chips. You can either program them in software, or save the config to on-board flash and pin-select various configs. They also have onboard varactors and EFC inputs for making a VCXO. The on-board VCXO range is 80 to 230 MHz, so I'd multiply the 10 MHz up to 160 MHz and then divide by 10. I like to throw one in a circuit and know that I can generate whatever clocks I need in software. They're also pin-compatible, so if you lay down a pad for a part larger than needed, you have spare outputs in case you need them for something. (The second digit in the P/N is the number of PLLs; the third is the number of outputs.) The main limitation is that there's no way to produce a desired phase relationship between different divisors for e.g. a half-speed clock. Looking for something cheaper, I can see SiLabs' Si51210 factory- programmable part, which is cheaper in quantity, but I don't know the minimum order quantities. It depends what you mean by simplest; the injection-locking idea is definitely the simplest circuit, but it does require some up-front work to find coupling capacitor values that work reliably over tolerance. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 02/01/2013 20:05, David J Taylor wrote: James, You might be interested in my write-up: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html and its performance: http://www.satsignal.eu/mrtg/performance_ntp.php I was playing with RasPi-1 today to see whether a different (navigation) GPS receiver or system configuration would make any difference to the oscillatory nature of the offset, hence the big step around 11:00 when the card was restarted after an hour's power down. RasPi-2 with a timing GPS receiver looks better, and it should have an identical configuration to RasPi-1 (except that the USB port is being sent data). Cheers, David Interesting stuff indeed - the timing receiver certainly looks much more stable, which is to be expected. I'm not seeing quite as much stability on my Pi/setup - http://i.imgur.com/6L8ur.png is the munin-measured kernel offset for the last day. I've only been running it for a few days but I'd have thought the clock loop should've stabilized a bit more than it has at present. Could be that this particular GPS receiver isn't managing very well at all to give particularly precise PPS pulses, which is possible given it's a navigational receiver. The datasheet specifies a 60nsec accuracy but it's unclear if that relates to the 1PPS output. Once this one's been running for a few more days I should have some more interesting graphs; I'm getting one of my home boxes set up with Graphite so I can push more detailed statistics and information to that from the RPi about NTP etc and get a better feel for what's going on. Cheers, James -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.17 (MingW32) iEYEARECAAYFAlDkl9IACgkQ22kkGnnJQAyjxQCfUYma1e8MuRcWD8Ldk0IRHOKy lnQAoK8+Qr0DcADVwFJi0XtGvRC9hPx9 =5JMB -END PGP SIGNATURE- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Am 02.01.2013 19:54, schrieb Tom Van Baak: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. Probably not the simplest way, but straightforward maybe you can recycle parts of it: http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png That's how I did (optional) 10 MHz --- 32 MHz for my DG8SAQ VNWA. parts are cheap available @ digikey. regards, Gerhard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I looked at the TI chip that really seems simple. On Wed, Jan 2, 2013 at 3:58 PM, Gerhard Hoffmann dk...@arcor.de wrote: Am 02.01.2013 19:54, schrieb Tom Van Baak: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. Probably not the simplest way, but straightforward maybe you can recycle parts of it: http://www.hoffmann-**hochfrequenz.de/downloads/**vnwa_sync_1.1.pdfhttp://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf http://www.hoffmann-**hochfrequenz.de/downloads/**vnwa_sync_1.1_layout.pnghttp://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png That's how I did (optional) 10 MHz --- 32 MHz for my DG8SAQ VNWA. parts are cheap available @ digikey. regards, Gerhard __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I wrote: The on-board VCXO range is 80 to 230 MHz, so I'd multiply the 10 MHz up to 160 MHz and then divide by 10. In case it's not obvious, I meant to write the on-chip VCO. Obviously it's *not* a crystal oscillator; I just failed to supervise my typing fingers carefully enough. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Undocumented FE5680A commands, and a python script
Hello, I've read about undocumented FE5680A commands (On excellent Didier' FE5680 FAQ page). This python script is a collection of the functions I'm using to connect to FE5680: http://pastebin.com/VpZVuw0t And I will add to it more functions based on these new fields. I'd like to know if anybody have worked out more details about these commands. Thanks, Fabio. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
On 1/2/13 11:37 AM, Poul-Henning Kamp wrote: Actually, the OS is not important, floating point support is. floating point support in the sense that the compiler supports it and generates appropriate code to use software FP or hardware FP as available? Or you need HW floating point for performance. (after all, I ran floating point FORTRAN code on a 4 MHz Z80 with 48k back in the late 70s... not speedy, but it works) We just went through an exercise to enable the use of HW FP on our SPARC processors for flight use. The original gcc tool chain RTEMS setup used software FP, even though the hardware has an FPU. But to implement the GPS receiver, we needed HW FP, so we had to work through all those issues. I don't recall precisely what the issues were (probably something about saving/restoring FPU registers or, at least, not tampering with their contents through an interrupt or library call). The problem wasn't that GCC couldn't generate the right object code, it was something more high level than that. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
The optimum width of the injection pulse is equal to 1/2 the period of the output frequency of the injection locked oscillator. In this case a pulse width of around 31.25ns Bruce paul swed wrote: Bruce is right about that fact. Thanks. Square up the 10 Mhz. Diff the leading edge (It actually doesn't matter) maybe 2-5pf cap and 300 ohm R to ground. Feed this into a transistor that is in the bottom end of a one transistor oscillator. There are actually several ways to inject. Think of a totem pole of 2 transistors. Use google and do a search and you will see what I am talking about. There were some articles that the spread spectrum hams used that describe it. On Wed, Jan 2, 2013 at 2:48 PM, Bruce Griffiths bruce.griffi...@xtra.co.nzwrote: Since injection locking is possible when the ratio of the 2 frequencies involved is a rational number, a 16 MHz oscillator can be directly injection locked to a 10MHz signal without the need for dividers etc. Bruce paul swed wrote: Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baakt...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/**mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
On Wed, Jan 2, 2013 at 12:37 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: Actually, the OS is not important, floating point support is. That is one reason that the recent crop of inexpensive ARM Cortex M4 experimenter boards is quite interesting. I picked up two of the TI Stellaris Launchpads on preorder for $5 each and also snagged a free STM32F3 board (both are Cortex M4). I haven't gotten to them yet, but I have projects in mind (always too many projects and not enough time). I just finished reading a book that described the STM Cortex line in detail. All I can say is wow. What you get for the money is quite impressive. Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
Hi That's the point I've been trying to make for about a month now. At some point, for a hobby project, the cost of the CPU becomes irrelevant. In my book, once the CPU goes below the price of lunch at McDonalds, it really doesn't matter much. Bob On Jan 2, 2013, at 7:36 PM, Joseph Gray jg...@zianet.com wrote: On Wed, Jan 2, 2013 at 12:37 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: Actually, the OS is not important, floating point support is. That is one reason that the recent crop of inexpensive ARM Cortex M4 experimenter boards is quite interesting. I picked up two of the TI Stellaris Launchpads on preorder for $5 each and also snagged a free STM32F3 board (both are Cortex M4). I haven't gotten to them yet, but I have projects in mind (always too many projects and not enough time). I just finished reading a book that described the STM Cortex line in detail. All I can say is wow. What you get for the money is quite impressive. Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
On 1/2/13 4:46 PM, Bob Camp wrote: Hi That's the point I've been trying to make for about a month now. At some point, for a hobby project, the cost of the CPU becomes irrelevant. In my book, once the CPU goes below the price of lunch at McDonalds, it really doesn't matter much. yes.. it's all about ease of interfacing and ease of programming. (unless you're making hundreds or 1000s of them) This is why Arduino is so popular.. dead simple for a lot of hackery kinds of things. The first steps on the learning stairway are pretty darn low (to the point that *artists* use them grin.. what is the world of computers coming to?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
Hi Arduino's original popularity was based on low cost. These days you can get a *lot* more for your money. Bob On Jan 2, 2013, at 8:07 PM, Jim Lux jim...@earthlink.net wrote: On 1/2/13 4:46 PM, Bob Camp wrote: Hi That's the point I've been trying to make for about a month now. At some point, for a hobby project, the cost of the CPU becomes irrelevant. In my book, once the CPU goes below the price of lunch at McDonalds, it really doesn't matter much. yes.. it's all about ease of interfacing and ease of programming. (unless you're making hundreds or 1000s of them) This is why Arduino is so popular.. dead simple for a lot of hackery kinds of things. The first steps on the learning stairway are pretty darn low (to the point that *artists* use them grin.. what is the world of computers coming to?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Tom, This may not be the answer you are looking for, but the simplest way may be to use a uC that has a PLL for clock generation. Didier On Wed, Jan 2, 2013 at 12:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
+1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? On 3 January 2013 06:25, Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Jan 2, 2013 at 11:16 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: I've given up on PIC and Atmel microcontrollers and their antiquated CPU designs. My life is too short to fight odd-ball compilers, when I can get a real 32 bit CPU and a good compiler instead. That is a valid point if you are building a one-off project. Your time is worth something. But if you plan to sell a million AA cell battery chargers using a 32-bit controller is uneconomical. These will always be a bigger market for 8-bit chips then for 32-bit chips. For an NTP server I'd go with something that can run an OS and the NTP reverence implementation. ARM (and others) can do that. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
On 1/2/13 5:34 PM, Tom Harris wrote: +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? Well, one might not need a full-up multitasking OS, but I'd sure like to have a high level interface to the network (say BSD sockets or something like that). And most OSes (or OS-like infrastructure) also gives you some handy stuff like timers, threads, queues, etc. If you are doing something that is TRULY single function, the one big loop scheme can work, particularly if you've got a lot of nice libraries to do stuff like string handling/parsing/device interaction. I think the dividing line might be where you are trying to do more than one thing with different time scales. It would be straightforward to do something like multiple PID loops with a common sample/update rate (like a lot of PLC industrial controllers do), but as soon as you start running things at different rates (check the Ethernet, check the serial port, update the loop, etc.) having an OS to do the book-keeping is pretty nice. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
On 01/02/2013 08:34 PM, Tom Harris wrote: Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? You certainly do not need an OS. For this project I am using a RTOS called ChibiOS that provides a threading interface and handles the tedium of flinging packets as well as timers, serial, etc. but it's not an OS in the same sense as Linux is and I'm still interacting directly with the critical peripherals. Since the PPS measurements are being done in dedicated hardware and the Ethernet interface is a hard-wired MAC and not USB, it performs quite a bit better than something with the overhead of a managed OS. Raspberry Pi and some other Linux-ready boards I've seen also use Ethernet interfaces built into the USB host, not quite sure why that's more cost-effective but it's sure to result in much poorer jitter versus a direct MAC. I'm using a F1 part which does not have a FPU, so all the math is 64bit integers. Soft floats are also an option, and for even the fanciest GPSDO there's not nearly enough number crunching going on to make a FPU absolutely necessary. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] clock-block any need ?
On 02/01/13 02:57, Dennis Ferguson wrote: On 27 Dec, 2012, at 15:13 , Magnus Danielsonmag...@rubidium.dyndns.org wrote: On GE, a full-length packet is about 12 us, so a single packets head-of-line blocking can be anything up to that amount, multiple packets... well, it keeps adding. Knowing how switches works doesn't really help as packets arrive in a myriad of rates, they interact and cross-modulate and create strange patterns and dance in interesting ways that is ever changing in unpredictable fashion. I wanted to address this bit because it seems like most people base their expectations for NTP on this complexity, as does the argument being made above, but the holiday intervened. While I suspect many people are thoroughly bored of this topic by now I can't resist completing the thought. Be advised that it was the short description of a much lengthier discussion. Yes, the delay of a sample packet through an output queue will be proportional to the number of untransmitted bits in the queue ahead of it, yes, the magnitude of that delay can be very large and largely variable and, even, yes, the statistics governing that delay may often be unpredictable and non-gaussian, exhibiting dangerously heavy tails. The thing is, though, that this doesn't necessarily have to matter so much. A better approach might avoid relying on the things you can't know. Hard to avoid fundamental properties of transmission, at least when they have been made fundamental properties. Recall that the queue length is quantized in steps, and that various padding (preamble-sequence, header, trailer, postamble-sequence) occurs. 8-bit quantization is safe to assume as minimum step for GE, due to its 8B10B encoding format on the optical channel. For optical GE, event resolution is therefore 8 ns. To see how, consider a different question: what is the probability that any two samples sent through that queue will experience precisely the same delay (i.e. find precisely the same number of bits queued in front of it when it gets there)? I think it is fairly conservative to predict that the probability that two samples will arrive at a non-empty output queue with exactly the same number of bits in front of them will be fairly small; the number of bits in the queue will be continuously changing, so the delay through a non-empty queue should have a near-continuous (and unpredictable) probability distribution, as you point out, and if the sampling is uncorrelated with the competing traffic it is unlikely that any pair of samples will find exactly the same point on that distribution. Yes and no. It is hard to do with a low asking rate, but some properties can improve with a high asking rate. The exception to this, of course, is a queue length of precisely 0 bits (which is precisely why the behaviour of a switch with no competing traffic is interesting). The vast majority of queues in the vast majority of network devices in real networks are no where near continuously occupied for long periods. The time-averaged fractional load on the circuit a queue is feeding is also the probability of finding the queue not-empty. If the average load on the output circuit is less than 100% then multiple samples are probably going to find that queue precisely empty; if the average load on the output circuit is 50% (and that would be an unusually high number in a LAN, though maybe less unusual in other contexts) then 50% of the samples that pass through that queue are going to find it empty. Since samples that found the queue empty will have experienced pretty much identical delays, the results (for some value of result) from those samples will cluster closely together. The results from samples which experienced a delay will differ from that cluster but, as discussed above, will also differ from each other and generally won't form a cluster somewhere else. The cluster marks the good spot independent of the precise (and precisely unknowable) nature of the statistics governing the distribution of samples outside the cluster. If we can find the cluster we have a result which does not depend on understanding the precise behaviour of samples outside the cluster. Whenever you want to do this, you need to measure the network more furiously, those the asking rate goes up. Given this it is also worth while to consider jitter, which intuition based on a normal distribution assumption might suggest should be predictive of the quality of the result derived from a collection of samples. In the situation above, however, the dominant contributors to jitter, however measured, are going to be the samples outside the cluster since they are the ones that are jittering (it is that property we are relying on to define the cluster). If jitter mostly measures information about the samples the estimate doesn't rely on then it tells you little about the samples the estimate does rely on, and hence can provide no prediction about the quality
Re: [time-nuts] An embedded NTP server
On 03/01/13 03:26, Jim Lux wrote: On 1/2/13 5:34 PM, Tom Harris wrote: +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? Well, one might not need a full-up multitasking OS, but I'd sure like to have a high level interface to the network (say BSD sockets or something like that). And most OSes (or OS-like infrastructure) also gives you some handy stuff like timers, threads, queues, etc. If you are doing something that is TRULY single function, the one big loop scheme can work, particularly if you've got a lot of nice libraries to do stuff like string handling/parsing/device interaction. It fails quite quickly if you have not though through the real time execution needs. Essentially, what execute when, triggered by what, with what data and how late can it be, and what else needs to be done? Real time properties does not need to be resolved by a real-time operating system, but it needs to be resolved by doing the real time analysis, and then attempting to find stable solutions. Bare-bone processors can work just as well, but things like HW-drivers, lack of network support etc. can be trouble-some. I think the dividing line might be where you are trying to do more than one thing with different time scales. It would be straightforward to do something like multiple PID loops with a common sample/update rate (like a lot of PLC industrial controllers do), but as soon as you start running things at different rates (check the Ethernet, check the serial port, update the loop, etc.) having an OS to do the book-keeping is pretty nice. If it gives the needed infrastructure. It can just as well keep the confusion high enough that the issues becomes fuzzidized enough for you not to see them clearly. Also, do not underestimate what a little HW/FW-support can do to relax requirements significantly, or for that matter seemingly trivial OS support features. HW/FW timestamping is one. Good quality timer support another. Just grabbing an RTOS and believing that it will solve all problems will not work. I've seen it fail miserably. I all to often see people expecting a few lines of code to solve bad system design, so do the system design and figure out your needs, then figure out what hardware and software platforms support those needs the best. You end up with a few alternatives and then iterate a good solution. It's always in the nitty gritty details, so few wide assumptions work very well. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
how about a Propeller? 8 cpu's no waiting :-) Don Magnus Danielson On 03/01/13 03:26, Jim Lux wrote: On 1/2/13 5:34 PM, Tom Harris wrote: +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? Well, one might not need a full-up multitasking OS, but I'd sure like to have a high level interface to the network (say BSD sockets or something like that). And most OSes (or OS-like infrastructure) also gives you some handy stuff like timers, threads, queues, etc. If you are doing something that is TRULY single function, the one big loop scheme can work, particularly if you've got a lot of nice libraries to do stuff like string handling/parsing/device interaction. It fails quite quickly if you have not though through the real time execution needs. Essentially, what execute when, triggered by what, with what data and how late can it be, and what else needs to be done? Real time properties does not need to be resolved by a real-time operating system, but it needs to be resolved by doing the real time analysis, and then attempting to find stable solutions. Bare-bone processors can work just as well, but things like HW-drivers, lack of network support etc. can be trouble-some. I think the dividing line might be where you are trying to do more than one thing with different time scales. It would be straightforward to do something like multiple PID loops with a common sample/update rate (like a lot of PLC industrial controllers do), but as soon as you start running things at different rates (check the Ethernet, check the serial port, update the loop, etc.) having an OS to do the book-keeping is pretty nice. If it gives the needed infrastructure. It can just as well keep the confusion high enough that the issues becomes fuzzidized enough for you not to see them clearly. Also, do not underestimate what a little HW/FW-support can do to relax requirements significantly, or for that matter seemingly trivial OS support features. HW/FW timestamping is one. Good quality timer support another. Just grabbing an RTOS and believing that it will solve all problems will not work. I've seen it fail miserably. I all to often see people expecting a few lines of code to solve bad system design, so do the system design and figure out your needs, then figure out what hardware and software platforms support those needs the best. You end up with a few alternatives and then iterate a good solution. It's always in the nitty gritty details, so few wide assumptions work very well. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Interesting problem Re: 10 MHz - 16 MHz clock multiplier What is low cost?? Serious question. john k6iql -Original Message- From: time-nuts-request time-nuts-requ...@febo.com To: time-nuts time-nuts@febo.com Sent: Wed, Jan 2, 2013 9:19 pm Subject: time-nuts Digest, Vol 102, Issue 10 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-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@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: 10 MHz - 16 MHz clock multiplier (Didier Juges) 2. Re: An embedded NTP server (Tom Harris) 3. Re: An embedded NTP server (Jim Lux) 4. Re: An embedded NTP server (Michael Tharp) 5. Re: clock-block any need ? (Magnus Danielson) -- Message: 1 Date: Wed, 2 Jan 2013 19:31:52 -0600 From: Didier Juges shali...@gmail.com To: Tom Van Baak t...@leapsecond.com, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier Message-ID: CAMQqFu=ghst14ygddgw8pvjrnmnryyfne13g06p+qrmv48a...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Tom, This may not be the answer you are looking for, but the simplest way may be to use a uC that has a PLL for clock generation. Didier On Wed, Jan 2, 2013 at 12:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Message: 2 Date: Thu, 3 Jan 2013 12:34:15 +1100 From: Tom Harris celephi...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] An embedded NTP server Message-ID: cahjg12qxpb9px8dp6ngk-x575etnsfc+csqr6acsrx7gfw-...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? On 3 January 2013 06:25, Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Jan 2, 2013 at 11:16 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: I've given up on PIC and Atmel microcontrollers and their antiquated CPU designs. My life is too short to fight odd-ball compilers, when I can get a real 32 bit CPU and a good compiler instead. That is a valid point if you are building a one-off project. Your time is worth something. But if you plan to sell a million AA cell battery chargers using a 32-bit controller is uneconomical. These will always be a bigger market for 8-bit chips then for 32-bit chips. For an NTP server I'd go with something that can run an OS and the NTP reverence implementation. ARM (and others) can do that. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com -- Message: 3 Date: Wed, 02 Jan 2013 18:26:24 -0800 From: Jim Lux jim...@earthlink.net To: time-nuts@febo.com Subject: Re: [time-nuts] An embedded NTP server Message-ID: 50e4ec50.1030...@earthlink.net Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 1/2/13 5:34 PM, Tom Harris wrote: +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
How about simply using a 16MHz GPSDO? We have shipped FireFly-1A units with 16MHz Ocxo.. Those can also generate 16MHz out of a 1PPS reference. Bye, Said Sent From iPhone On Jan 2, 2013, at 12:58, Gerhard Hoffmann dk...@arcor.de wrote: Am 02.01.2013 19:54, schrieb Tom Van Baak: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. Probably not the simplest way, but straightforward maybe you can recycle parts of it: http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png That's how I did (optional) 10 MHz --- 32 MHz for my DG8SAQ VNWA. parts are cheap available @ digikey. regards, Gerhard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Tom For simple, cheap, low performance and fast to build with junk box parts, hard to beat: What I made long ago for myself (before time-nut days). I still use it today for low end stuff, and it is all done with standard 74HC DIP parts. The main IC is a 74HCT4046 Phase lock loop with internal Osc. The internal osc output is divided by 16 using a 74HC93. The 10MHz ref is divide by 10 using a 74HC90 The two 1 MHz signals are feed into it's phase comparator. A couple of resistors and caps and I have a low tech 16 / 8 / 4 / 2 / 1 MHz tracking ref. With a couple of tweaks, I got the noise jitter down to a couple of ns as measured with a scope. 16 MHz is pushing the limits of the internal Osc, but I did not have any trouble getting there using less than the recommended osc cap. ws What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
On 02/01/13 19:54, Tom Van Baak wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? One approach is to divide by 5 to get 2 MHz, but recalling that the 20% PWM factor (top bit of divide by 5 counter) has a strong 8th overtone compared to the 40% PWM factor, an LC-tank at 16 MHz and a simple gain-stage (such as the Wenzel sine input) should be able to pull it off. The divide by 5 is standard TTL/CMOS of your choosing. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] An embedded NTP server
Not only SSH access, loggin g things like DNS lookup and rading the ntp.comf file from local (flash?) memory. And then without an OS you'd have to implement sceduling and process creation yourself. How else to accept SSH log ins, talk to multiple NT clients and yu reference clocks and write to the log server all at the same time? The trouble is that if you decide to go with an OS all of this becomes easy because it is already available for ARM and any other platforms the OS runs on. On Wed, Jan 2, 2013 at 10:44 PM, David J Taylor david-tay...@blueyonder.co.uk wrote: From: Tom Harris +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? == Having an OS makes access to things like SNMP for monitoring, SSL for control, and Samba for log extraction and management easier. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
