Re: [time-nuts] Modern HW replacement for ATOM based NTP server?
The ball bearing fan upgrade is the best idea. Bater idea is to put in a temperature controlled fan so it will spin slow or stop most of the time. I don't see the need to run each server on it's own hardware. Put the cashing DNS server on the same box as the NTP server. Or if you do have two boxes run the NTP server on both In terms of performance, ARM based credit card sized computers do well if you can get the PPS to the general purpose I/O pin that interrupts on an edge. the Pi can't do that the BeagleBone Black can and it sell for $45. It can share a power supply with your Thunderbolt, literally, no fan and it can just steel power from any GPS receiver. The BBB can like run a DNS server at the same time On Mon, Apr 6, 2015 at 3:29 PM, Frank Hughes via time-nuts time-nuts@febo.com wrote: Hi,Years ago this forum helped me put together my first GPSDO and NTP server. Using a then-popular INTEL ATOM board, FreeBSD w/ the NTP kernel, 1PPS input from aTB, works great. But as the years go by, HW improves/evolves and it might be time to recreate this functionin some other modern HW. Looking for a platform not needing a fan. While the ATOM and SSD seem to be OK w/o direct airflow, the Mini ITX Power Supply fan is needed. After three years, the stupid sleeve bearings are beginning to rattlewhich led me to this design review. Recently built a Caching DNS for the home LAN using a Technologic Systems TS-7250-V2, general purpose PC/104 embedded system Runs Debian, 3.14 kernel. Hardware Description:800 MHz CPU (PXA166)512 MB RAMMicro SD card socketRTC with battery and temp compensationTemp Sensor10/100 ethernet port2 USB HS Host ports3x RS-232 serial ports3x TTL serial portsRS-485 portPC/104 connectorUSB device console port (Micro B connector)LCD and DIO Headers75 TTL DIO (including PC/104 conn)5VDC or 8-28VDC power inputA/D converter, 5 channels (with 4-20 mA current loop) A more expensive alternative to the Pi, but reasonable. Wondering if a TS-7250-V2 is worth a try for the NTP function, or if anyone here has already used one of thesefor NTP? Or other non-Pi alternatives? I would very much appreciate some guidance as to the HW/SW combinationthat would best replace the existing NTP server. - 1PPS is available from both a Trimble TB and a Jackson Labs Fury, so I could build a parallel system. Or just put a ball-bearing fan in...73Frank HughesKJ4OLL ___ 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.
Re: [time-nuts] Modern HW replacement for ATOM based NTP server?
I think beagle bone black is the answer to this question (because rPi has a USB-network interface that´s problematic) but i´ll let others that know more than me about this specific subject follow on Daniel On 06/04/2015 19:29, Frank Hughes via time-nuts wrote: Hi,Years ago this forum helped me put together my first GPSDO and NTP server. Using a then-popular INTEL ATOM board, FreeBSD w/ the NTP kernel, 1PPS input from aTB, works great. But as the years go by, HW improves/evolves and it might be time to recreate this functionin some other modern HW. Looking for a platform not needing a fan. While the ATOM and SSD seem to be OK w/o direct airflow, the Mini ITX Power Supply fan is needed. After three years, the stupid sleeve bearings are beginning to rattlewhich led me to this design review. Recently built a Caching DNS for the home LAN using a Technologic Systems TS-7250-V2, general purpose PC/104 embedded system Runs Debian, 3.14 kernel. Hardware Description:800 MHz CPU (PXA166)512 MB RAMMicro SD card socketRTC with battery and temp compensationTemp Sensor10/100 ethernet port2 USB HS Host ports3x RS-232 serial ports3x TTL serial portsRS-485 portPC/104 connectorUSB device console port (Micro B connector)LCD and DIO Headers75 TTL DIO (including PC/104 conn)5VDC or 8-28VDC power inputA/D converter, 5 channels (with 4-20 mA current loop) A more expensive alternative to the Pi, but reasonable. Wondering if a TS-7250-V2 is worth a try for the NTP function, or if anyone here has already used one of thesefor NTP? Or other non-Pi alternatives? I would very much appreciate some guidance as to the HW/SW combinationthat would best replace the existing NTP server. - 1PPS is available from both a Trimble TB and a Jackson Labs Fury, so I could build a parallel system. Or just put a ball-bearing fan in...73Frank HughesKJ4OLL ___ 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] Modern HW replacement for ATOM based NTP server?
On Mon, Apr 6, 2015 at 5:29 PM, Frank Hughes via time-nuts time-nuts@febo.com wrote: Looking for a platform not needing a fan. While the ATOM and SSD seem to be OK w/o direct airflow, the Mini ITX Power Supply fan is needed. After three years, the stupid sleeve bearings are beginning to rattlewhich led me to this design review. Recently built a Caching DNS for the home LAN using a Technologic Systems TS-7250-V2, general purpose PC/104 embedded system Runs Debian, 3.14 kernel. Beagle Bone Black. -- Brian Lloyd 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ 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] Modern HW replacement for ATOM based NTP server?
On Mon, 6 Apr 2015 22:29:23 + (UTC) Frank Hughes via time-nuts time-nuts@febo.com wrote: Looking for a platform not needing a fan. While the ATOM and SSD seem to be OK w/o direct airflow, the Mini ITX Power Supply fan is needed. That depends highly on how much knowledge in linux and especially embedded linux you have. If you know how to build your own kernel, what initrd means and today it's actually initramfs and not initrd and you do not fear to build whole software systems by hand, then you can go for one of the many embedded boards. The beaglebone black, the minnow max and SAMA5D come to mind. The Minnow Max has the advantage of being an x86 based system and thus behaves very much like it (not completely though). The BBB has a huge supporting community and you can find a lot of information online. The SAMA5D based systems are nice because Atmel seems to care very much about proper support in the kernel. If you don't feel confortable with the challenges of an embedded system, i would recommend to stick with an ITX (or smaller) PC. Eg The APU[1] from pc-engines, which is the successor of his successful ALIX boards. Pascal Dornier is very helpfull if you have any issues with his boards, and full documentation (including schematics) is online. Attila Kinali [1] http://www.pcengines.ch/apu.htm -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] Need advice for multilateration setup
On Mon, 06 Apr 2015 23:02:01 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: You want to keep your chip-rate up to make the integer ambiguity of the carrier phase simple. The carrier frequency divided by chipping rate ratio indicate how difficult problem it is to solve (GPS L1 C/A code has 1540). The 70 cm band has rather narrow allocations. The 23 cm band allow for much wide allocations. The benefit of the 70 cm band is naturally the easy of getting hardware. Yes. But I would do carrier phase tracking only after code phase tracking proved to be not accurate enough. Improving later and switching to another band is relatively easy, once you've proven that the system in principle works. Another benefit of a higher chipping rate is that it can allow for a higher bandwidth, allowing for tighter tracking of the rocket dynamics. The chipping rate at some code legnth creates the maximum tracking rate, and some fraction of that is the highest bandwidth tolerable. That's a very good argument for higher chiping rates. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] 53230A noise floor
Tangetially relevant; I made a patch for TimeLab to use the gap-free frequency measurement-mode for the 53230A, if anyone is interested. On Fri, Apr 3, 2015 at 4:34 PM, Tom Van Baak t...@leapsecond.com wrote: There is probably a good explanation for the ADEV-level in standard (pi-counting?) reciprocal frequency counter mode as well as the roughly 1/sqrt(10) enhancement in ADEV when increasing the gate-time 10-fold. Anders, See the part the end that shows why averaging breaks ADEV: http://leapsecond.com/pages/adev-avg/ I collected the data with a simple program that just calls the READ? function repeatedly, which does result in some dead-time between measurements. Yes, that's the easy way. But for more valid results use gap-free continuous mode (SENS:FREQ:MODE CONT). From the manual: CONTinuous configures the instrument to make continuous resolution-enhanced, gap-free measurements. This mode should be selected for true Allan deviation computation (CALCulate:AVERage subsystem). In this mode, all samples for a each trigger are started by a single gate open (instead of gate open/close per sample), and the measurements are computed back-to-back with no dead time. CONTinuous can only be used for frequency and average period measurements. Available only on the Agilent 53230A. /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] Modern HW replacement for ATOM based NTP server?
albertson.ch...@gmail.com said: In terms of performance, ARM based credit card sized computers do well if you can get the PPS to the general purpose I/O pin that interrupts on an edge. the Pi can't do that the BeagleBone Black can and it sell for $45. What/why can't the Pi do? I have one handy that is processing a PPS on a GPIO pin. David Taylor has a web page with all the fine print on how to set it up. (Thanks.) -- These are my opinions. I hate spam. ___ 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] Modern HW replacement for ATOM based NTP server?
Internally the rPI is a ver awkward beast: the CPU is connected to a GPU, and the GPU is connected to the GPIOs... so lots of jitter and latency. It was designed to be a video decoder... the CPU is there for testing and housekeeping. It works, surelly, but it´s not designed to have low latency and jitter. Daniel On 07/04/2015 09:39, Hal Murray wrote: albertson.ch...@gmail.com said: In terms of performance, ARM based credit card sized computers do well if you can get the PPS to the general purpose I/O pin that interrupts on an edge. the Pi can't do that the BeagleBone Black can and it sell for $45. What/why can't the Pi do? I have one handy that is processing a PPS on a GPIO pin. David Taylor has a web page with all the fine print on how to set it up. (Thanks.) ___ 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] Modern HW replacement for ATOM based NTP server?
On Mon, Apr 6, 2015 at 6:29 PM, Frank Hughes via time-nuts time-nuts@febo.com wrote: Or just put a ball-bearing fan in Sites like lilliputing follow the low power/embedded market. I'd suggest starting there. All of my low power systems use power bricks. This includes mini-itx boards. I've had bad experience with a Minnow board and a Sheva. Okay experience with BeagleBoneBlack and RaspberryPi. Good experience with Compulab fit-PC2 systems and Jetway mini-itx fanless boards (the latter two using Atom CPUs). Very good experience with Supermicro fanless mini-itx. It turns out that list is also mostly sorted by price. ___ 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] Need advice for multilateration setup
Hi, On 04/07/2015 02:08 PM, Attila Kinali wrote: On Mon, 06 Apr 2015 23:02:01 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: You want to keep your chip-rate up to make the integer ambiguity of the carrier phase simple. The carrier frequency divided by chipping rate ratio indicate how difficult problem it is to solve (GPS L1 C/A code has 1540). The 70 cm band has rather narrow allocations. The 23 cm band allow for much wide allocations. The benefit of the 70 cm band is naturally the easy of getting hardware. Yes. But I would do carrier phase tracking only after code phase tracking proved to be not accurate enough. Improving later and switching to another band is relatively easy, once you've proven that the system in principle works. One might look at the available frequencies and see if there is a telemetry band available which allows wider bandwidth. For the application, I don't see that very much transmitted power is needed. There is definitely a benefit in locking up the carrier and chipping rate, preferably so that there is an integer number of carrier cycles per chip. For those unused to the terminology, a chip is a single 0 or 1 out of the pseudo-random generator. It's encoded as +1 or -1 before being mixed with the carrier, thus forming an BPSK signal. There is a gain for the receiver if the transmitter has the carrier and code synchronized to each other like this. Another benefit of a higher chipping rate is that it can allow for a higher bandwidth, allowing for tighter tracking of the rocket dynamics. The chipping rate at some code legnth creates the maximum tracking rate, and some fraction of that is the highest bandwidth tolerable. That's a very good argument for higher chiping rates. I expect that the launch is a bit challenging for the tracking loop. Much of these challenges should be relatively easy to simulate, such that testing can be done before a the first solder-joint gets soldered. 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] Modern HW replacement for ATOM based NTP server?
I think beagle bone black is the answer to this question (because rPi has a USB-network interface that´s problematic) but i´ll let others that know more than me about this specific subject follow on Daniel == Problematic if you are after microsecond-level accuracy, perhaps, but so would the BeagleBone be. If your needs are more in the 100 microsecond range, either would be fine with a reasonably wide PPS pulse. Yes, the BeagleBone is somewhat better at serving externally according to my own tests, but the Raspberry Pi has the greatest support in the community, if you want to use it for other tasks as well, and doesn't suffer from the problem of generating RF interference at GPS frequencies. Both are excellent little devices! 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.
Re: [time-nuts] Mini-time lab cost and maintenance
Every timelab needs a time interval counter. I'd say look for a HP 5334B with option 010. I've picked up two from ebay for about USD100 each, and that comes with a decent 18011. After that, watch your cash disappear as you discover a need for faster/better/more accurate instruments, not to mention better and better oscillators.. Ole On Tue, Apr 7, 2015 at 12:33 AM, Chris Albertson albertson.ch...@gmail.com wrote: You can do a lot for $200 if you can build electronics yourself. Decent GPS with PPS starts at under $20 on eBay. Same for surplus 10MHz oscillators. People have build usable counters for cheap microprocessor development boards and software.But it all depends on what you want to measure On Mon, Apr 6, 2015 at 9:30 AM, Adam Blakney akblak...@gmail.com wrote: I was wondering how expensive it would be to have even a small and lower level time lab. What are some less expensive models of machinery i would need, and how much maintenance is required? Thanks, Adam ___ 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. ___ 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] 53230A noise floor
Ole Petter Ronningen: Tangetially relevant; I made a patch for TimeLab to use the gap-free frequency measurement-mode for the 53230A, if anyone is interested. Thanks for this great support! Ulli ___ 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] Modern HW replacement for ATOM based NTP server?
On Tue, 7 Apr 2015 17:39:01 +0100 David J Taylor david-tay...@blueyonder.co.uk wrote: Problematic if you are after microsecond-level accuracy, perhaps, but so would the BeagleBone be. If your needs are more in the 100 microsecond range, either would be fine with a reasonably wide PPS pulse. Not really. If you know how to write C, you can use the timer on the BBB and get to sub-us accuracy levels (IIRC ~10ns). The biggest problem would be to get the data into ntp in the right way, as I am not sure whether ntp supports that kind of input. But I know at least someone working on this. The rpi has, AFAIK, no timer units Attila Kinali -- _av500_ phd is easy _av500_ getting dsl is hard ___ 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] Modern HW replacement for ATOM based NTP server?
Looking for a platform not needing a fan. While the ATOM and SSD seem to be OK w/o direct airflow, the Mini ITX Power Supply fan is needed. If you are happy with Raspberry Pi or BeagleBone Black, they are the low cost low power way to go. They run Linux. They don't have a real disk. If you do a lot of disk activity, you might wear out the SD card frequently enough to be annoying. That hasn't been a problem for me but I don't have a lot of years on them yet. You could use a USB disk. The Raspberry Pi has a HDMI connector so you can run a real display. The BBB has a mini/micro HDMI connector. I ignore those and ssh in from my main PC. (Some people refer to that mode of operation as headless.) You can get no-fan style power for Mini-ITX size systems. The ones I'm familiar with have a tiny DC-DC converter that mounts on the big power connector and runs off a laptop size external supply. http://www.mini-box.com/DC-DC You could just change the fan or whole power supply whenever the fan dies. Maybe you will get lucky and find one with a fan that lasts a long time. You could try an old laptop. The battery will decay over the years, but it will probably work well enough to cover short dropouts and/or let you wander around for a few minutes. Some laptops have fans. (I have a Dell Latitude D430. It has been running 24x7 for several years. The fan still works. The battery is only good for 10 or 15 minutes.) -- These are my opinions. I hate spam. ___ 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] Modern HW replacement for ATOM based NTP server?
Hi! Take a look at https://www.febo.com/pipermail/time-nuts/2014-December/089217.html and https://www.febo.com/pipermail/time-nuts/2014-December/089681.html. There you can see sub-microsecond accuracy. Edésio On Tue, Apr 07, 2015 at 09:52:57PM +0200, Attila Kinali wrote: On Tue, 7 Apr 2015 17:39:01 +0100 David J Taylor david-tay...@blueyonder.co.uk wrote: Problematic if you are after microsecond-level accuracy, perhaps, but so would the BeagleBone be. If your needs are more in the 100 microsecond range, either would be fine with a reasonably wide PPS pulse. Not really. If you know how to write C, you can use the timer on the BBB and get to sub-us accuracy levels (IIRC ~10ns). The biggest problem would be to get the data into ntp in the right way, as I am not sure whether ntp supports that kind of input. But I know at least someone working on this. The rpi has, AFAIK, no timer units Attila Kinali -- _av500_ phd is easy _av500_ getting dsl is hard ___ 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] Need advice for multilateration setup
On 4/7/15 11:33 AM, Magnus Danielson wrote: Hi, O One might look at the available frequencies and see if there is a telemetry band available which allows wider bandwidth. For the application, I don't see that very much transmitted power is needed. If the OP is a licensed amateur radio person, then choosing one of the low microwave ham bands would be easy. Parts to generate a carrier and BPSK at 2.39-2.45,3.3-3.5, 5.6-5.8 GHz are cheap and readily available. You might be able to get away with a VCO and no crystal as the transmitter, but even if you can't, there's tons of PLLs out there that will nicely lock to a crystal and are cheap. You might want to do a link budget and see how much power you need to radiate, so that you get a decent SNR at the receiver. free space path loss between isotropic antennas (in dB) = 34 + 20 log10(freq in MHz) + 20 log10(distance in km). 1km at 3 GHz is 34+69 = 103 dB. If you radiate 1 mW (0dBm) from an omni (a piece of wire), you'll see -103 dBm at the input to your receiver, which is a fairly healthy signal. A detection bandwidth of 10 Hz would have a noise floor of -164 dBm before taking into account the receiver noise, but even if the receiver is terrible, you're still looking at tens of dB SNR with a very simple transmitter. That's a very good argument for higher chiping rates. I expect that the launch is a bit challenging for the tracking loop. If you're trying to track in real time, certainly. If you're doing post processing, less so. ___ 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] Modern HW replacement for ATOM based NTP server?
Is the new RPi2 any different in that regard? On April 7, 2015 8:17:12 AM CDT, Daniel Mendes dmend...@gmail.com wrote: Internally the rPI is a ver awkward beast: the CPU is connected to a GPU, and the GPU is connected to the GPIOs... so lots of jitter and latency. It was designed to be a video decoder... the CPU is there for testing and housekeeping. It works, surelly, but it´s not designed to have low latency and jitter. Daniel On 07/04/2015 09:39, Hal Murray wrote: albertson.ch...@gmail.com said: In terms of performance, ARM based credit card sized computers do well if you can get the PPS to the general purpose I/O pin that interrupts on an edge. the Pi can't do that the BeagleBone Black can and it sell for $45. What/why can't the Pi do? I have one handy that is processing a PPS on a GPIO pin. David Taylor has a web page with all the fine print on how to set it up. (Thanks.) ___ 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. -- Sent from my Motorola Droid Razr HD 4G LTE wireless tracker while I do other things. ___ 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] Modern HW replacement for ATOM based NTP server?
Hi Now you need to sort out the B, the A+ and the B+ in the Raspberry world. There may be more that I have not yet noticed. As far as I can tell, they all are pretty limited once you get past the tight video integration on the B and B+. Bob On Apr 7, 2015, at 12:41 PM, Didier Juges shali...@gmail.com wrote: Is the new RPi2 any different in that regard? On April 7, 2015 8:17:12 AM CDT, Daniel Mendes dmend...@gmail.com wrote: Internally the rPI is a ver awkward beast: the CPU is connected to a GPU, and the GPU is connected to the GPIOs... so lots of jitter and latency. It was designed to be a video decoder... the CPU is there for testing and housekeeping. It works, surelly, but it´s not designed to have low latency and jitter. Daniel On 07/04/2015 09:39, Hal Murray wrote: albertson.ch...@gmail.com said: In terms of performance, ARM based credit card sized computers do well if you can get the PPS to the general purpose I/O pin that interrupts on an edge. the Pi can't do that the BeagleBone Black can and it sell for $45. What/why can't the Pi do? I have one handy that is processing a PPS on a GPIO pin. David Taylor has a web page with all the fine print on how to set it up. (Thanks.) ___ 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. -- Sent from my Motorola Droid Razr HD 4G LTE wireless tracker while I do other things. ___ 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] Modern HW replacement for ATOM based NTP server?
On 07/04/2015 17:58, Hal Murray wrote: If you are happy with Raspberry Pi or BeagleBone Black, they are the low cost low power way to go. They run Linux. They don't have a real disk. If you do a lot of disk activity, you might wear out the SD card frequently enough to be annoying. That hasn't been a problem for me but I don't have a lot of years on them yet. You could use a USB disk. You can configure the main partition to run read only. This improves lots of things in this regard. Daniel ___ 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.
