Re: [time-nuts] Time interval measurement vs dual mixer method
Hello to the group, Thanks for interesting discussion. I found a nice plot in"Measurement, Instrumentation, and Sensors Handbook, Second Edition", ( John G. Webster,Halit Eren), at 42-24 page. It shows that in short term stability (tau 1 - 10 s) dual mixer method is most sensible, in long term stability TIE and DM results are similar. I'm going to do the same mesurements with Rb standard (Pendulum 6689) as DUT. Data is now collecting. SD ___ 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] CSAC purchase
Hi I’m guessing there was a question to me that somehow got lost in the world of ones and zeros …. My comment was in terms of temperature stability. The CSAC has a temp stability specification of +/-4x10^-10 over -10 to +70C. There are TCXO’s that will get below 5x10^-9 over that range and use far less power. There are OCXO’s that will get to better temperature stability numbers over that range. Neither one will do the long term aging that a Rb will. Bob > On Jan 22, 2018, at 3:49 PM, jimlux wrote: > > On 1/22/18 12:05 PM, Ronald Held wrote: > >> Bob: >>OCXO and TCXO are larger then the CSAC? How much more power would >> they need to get within a factor of ten to the 1.5s/1000 years? >> Ronald > > > OCXO and TCXO are both available smaller than the CSAC (particularly tcxo). > I'm using a vectron EX-421 OCXO and it's about 1cm on a side, the OX205 is > about 1" square and maybe 0.60" tall. > > TCXOs are available in "cellphone" form factors (e.g. tiny SMT packages) > > ___ > 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] CSAC purchase
On 1/22/18 12:05 PM, Ronald Held wrote: Bob: OCXO and TCXO are larger then the CSAC? How much more power would they need to get within a factor of ten to the 1.5s/1000 years? Ronald OCXO and TCXO are both available smaller than the CSAC (particularly tcxo). I'm using a vectron EX-421 OCXO and it's about 1cm on a side, the OX205 is about 1" square and maybe 0.60" tall. TCXOs are available in "cellphone" form factors (e.g. tiny SMT packages) ___ 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Paride Legovini via time-nuts writes: > I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm > looking for a good and possibly affordable timing GPS receiver. Unless you plan to use the timing receiver for some other function, it really is overkill for the purpose of setting up an NTP server and otherwise also requires you to set up a proper antenna in order to benefit from the extra precision. > Am I overlooking something or missing interesting options? I think that setting up at least three "good enough" NTP stratum-1 servers in your network gets you much better synchronization than trying to get a single one more precise. To that end, you can set one up for around $60 if you use a raspberryPi and a NavSpark mini w/ patch antenna (if you have reasonable reception with that). You'll find that the NTP clients will not see any measurable improvement once you have the NTP servers down below 10µs deviation and it's possible to get each individual server consistently below 1µs with a bit of care. Having at least three stratum-1 in your network will keep the clients synchronized correctly when inevitably one of the servers will have the occasional problem that makes its time wander off for a while. Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ Factory and User Sound Singles for Waldorf Q+, Q and microQ: http://Synth.Stromeko.net/Downloads.html#WaldorfSounds ___ 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Yo Paride! On Mon, 22 Jan 2018 16:38:01 +0100 Paride Legovini via time-nuts wrote: > I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm > looking for a good and possibly affordable timing GPS receiver. Before you bother looking at any GPS, you need to look at your server. Hardly any Intel CPU can give you time resolution much better than 200 nS on a PPS in. Raspberry Pi's actually have slightly better clock resolution than Intel parts, just under 190 nS. That resolution os worse than what you get out of any good modern GPS. By 'local resolution' I mean the shortest time interval you can read by repeatedly doing clock_systime() calls. clock_system() is is many key ntpd paths. The accuracy of your NTP server will be strongly affected by your server choice, and the cheap RasPi is often one of the best for the job. Fot $70 you can get a RasPi and a u-blox-8 hat. Add a few bits here and there and you have a nifty stratum 1. You'll find its harder than it looks to make a better NTP than that combo. Then, once you have a strong baseline, you can see what tricks you can do to improve on that. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp_0UNQPV09D.pgp Description: OpenPGP digital 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] CSAC purchase
Hi For something portable, the good old RBXO approach might well be worth considering. Bob > On Jan 22, 2018, at 3:05 PM, Ronald Held wrote: > > Magnus: > I wanted one since they were announced in 2005, AFAIR. Incorporated > into a watch was my first choice, but that price is out of range. A > portable old cell phone size version is next. > Ronald > > > What exactly motivated specifically CSAC for you? > > There might be other cheaper alternatives to your problem. > > For me CSAC solves a problem within very specific set of parameters, > where low power consumption is one of them. Depending on the actual > details of the application a TCXO might be a better choice, or even some > OCXOs. > > It's not that I want to deny you the fun of toying with CSAC, I have > three myself, but if you don't really need what it is good for, other > choices might be better. Also, the one place for such advice is for sure > this email list where a lot of experience is gathered and ready to share. > > Cheers, > Magnus > > > Bob: > OCXO and TCXO are larger then the CSAC? How much more power would > they need to get within a factor of ten to the 1.5s/1000 years? > Ronald > ___ > 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] CSAC purchase
Magnus: I wanted one since they were announced in 2005, AFAIR. Incorporated into a watch was my first choice, but that price is out of range. A portable old cell phone size version is next. Ronald What exactly motivated specifically CSAC for you? There might be other cheaper alternatives to your problem. For me CSAC solves a problem within very specific set of parameters, where low power consumption is one of them. Depending on the actual details of the application a TCXO might be a better choice, or even some OCXOs. It's not that I want to deny you the fun of toying with CSAC, I have three myself, but if you don't really need what it is good for, other choices might be better. Also, the one place for such advice is for sure this email list where a lot of experience is gathered and ready to share. Cheers, Magnus Bob: OCXO and TCXO are larger then the CSAC? How much more power would they need to get within a factor of ten to the 1.5s/1000 years? Ronald ___ 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] Symmetricom TimeSource 2500
On Mon, 22 Jan 2018 13:17:40 -0500 Bruce Hunter via time-nuts wrote: > A disappointment of the 2500's architecture is that it burns an SRI PRS-10 in > the background as a backup in case of the loss of GPS. This seems wasteful > to me as the operating life of the PRS-10 units is not unlimited. I suppose > the PRS-10 could be disabled, but this would require some simulation > circuitry as the 2500 monitors the PRS-10 and goes into a fault condition if > the expected PRS-10 presence is absent. Certainly others have utilized these > units for such use. Has anyone performed a detailed evaluation of the 2500 > units in intermittent service? The PRS-10 is in there because someone needed the additional stability performance. And to achieve that you need to run it continuously, because you need to measure its frequency and correct it as it slowly drifts. As with crystal oscillators, Rb have a retrace as well, so just measuring the frequency and shutting it off, will not do. So, what you want is bascially switching off the main component of the system. Besides, switching an Rb on and off is not a good thing for its lifespan. It's like a incandescent light bulb: They can run for decades if continuously under power, but if you switch them on and off once a day, they die within a few months. Also, Rb are spec'ed for a lifespan in the order of 20 years (the PRS10 has a lifespan of 27 years). Nobody complains if a piece of equipment needs to be replaced/repaired every 20 to 30 years. Most likely the power supply will die well before you get even to the Rb failing. 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.
[time-nuts] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
I put my layout for a GPS RS-232 level converter board up on OSHPARK's shared projects. It has places for mounting the Trimble Res-T, the Adafruit Ultimate GPS, and the CN06 (Ublox 6M). The RS-232 circuit has a selectable polarity 1PPS ouput. You can use a3.3V or 5V regulator or there is a jumper for providing the receiver with the raw input power. https://oshpark.com/shared_projects/YPvKgMYa ___ 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] SI5328
On Mon, 22 Jan 2018 08:18:29 -0600 "Chris Caudle" wrote: > The DSP loop filter gives a really wide range of loop bandwidth, down to > fractional Hz for some parts. Using a DDS for the VCO gives a lot of > flexibility in output frequency selection, but means that there can be > problems with spurs. Part of the SiLabs secret sauce is supposed to > reduce spurs compared to a simpler NCO implementation, but I don't think > you can eliminate spurs entirely with any kind of DDS based design. The secret sauce is not so secret, actually. It's just how you build a higher order delta-sigma modulator. Most PLL implementations still use a 1st-order modulator, with the well known spur problem (they arise from the "idle-tone" problem in delta-sigma modulators) The "low-spur" fractional PLLs use a 2nd or 3rd order modulator. There has been some research in the last decade or so on how to reduce those spurs further (mostly using even higher order and some times using tricks like actively introducing errors to spread the spurs) and most of it can be found online on IEEE and the like. For a gentle introduction, have a look at Schreier, Pavan and Teme's book "Understanding Delta Sigma Data Converters." I find the idea of using two cascaded control loops neat. It helps to control erros (aka noise) contributed by the second (inner) loop. However, how this reduces suceptibility to vibration, I am not entirely sure. The reason why most people do not do this is easily explained: it's more difficult to get a stable system with nested loops, as the conditions for stability becomes more complex than with just a standard, straight forward PID loop. 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] SI5328
There are many small volume assmebly houses available. But the problem is that you will have setup costs in the order of at least 100-300€, even if you go to China. So, producing lots of less than 10 is not economical, probably should aim for 100. I recently ran across MacroFab (https://macrofab.com/), who can do small orders (quantity: 1) of boards, assembled, for what seems like reasonable prices. I haven't actually used them, but I did run a recent board through their process (except for actually ordering), and they came out with a price of ~$170 for a board that cost me ~$100 to assemble myself ($35 for board, ~$65 for BoM), so that's not too bad. I imagine the numbers would be smaller for simpler boards (this one is ~80 components and pretty big -- 110mm x 60mm). The price came down pretty quick for quantity 3 or 5 or 10, though I don't remember the specifics. The downside being that you have to be able to upload part-placement info that is actually correct. Most layout programs don't seem to have an issue generating it, though -- I just uploaded my gerbers and my KiCad PCB file and it just ran with it. FWIW, it's not that hard to do even fine-pitch SMD stuff onesself. There's a little bit of startup cost (you really want to build a proper reflow toaster), but with high quality PCBs available via OSHPark (and fast! My *four layer* board was ~10 days), and quality stencils available via OSHStencils, doing even fine-pitch SMD work at home is surprisingly easy. In most simple cases, you don't even need the stencils... -j ___ 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
On Mon, 22 Jan 2018 16:38:01 +0100 Paride Legovini via time-nuts wrote: > I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm > looking for a good and possibly affordable timing GPS receiver. > > As far as I can tell there are a few common options. One is the Trimble > Resolution T (or SMT), that should be good and proven. The major > annoyance is converting the 3.3V TTL serial logic-level to RS232, but > should be doable with a MAX3232 and a few capacitors. > > Another option is this UBLOX LEA-5T: > > https://www.ebay.it/itm/291769145465 > > The seller advertises an RS232 output pin, but I'm not sure it's > actually available, and I'd need at least lines, one for the NMEA > strings and one for the 1PPS signal. So, even if a RS232 TX pin is > actually there, it is probably not enough to build a good reference > clock, and I'd still need to convert some TTL levels to RS232... > > Does anybody have experience with this receiver? > How does it compare to the Resolution T/SMT? For raw GPS PPS output, your performance is limited by multi-path and how much of the sky you see. If you have perfect conditions, I expect both to perform at the same level. Under not so perfect conditions, go for the LEA. I have here a Trimble UCCM and Oscilloquartz Star4 GPSDO (using a LEA-5T). Compared to the Star4, the UCCM is basically deaf. And mind you, the LEA-5 family came out somewhen around 2006, ie is already a more than 10 year old design and probably of the same age as the UCCM. The modern LEA's got a few dB better yet. For an NTP server, where you wont need anything better than 1µs resolution, I think one of the many 10-bucks ublox LEA/NEO boards that you can find on ebay are good enough (standard navigation receivers give you better than 100ns accuracy). If you still want to have a timing receiver, then go for one of the NEO-M8T, LEA-M8T or LEA-6T based boards. Be aware that the NEO modules do not have the circuit to provide power to the antenna, so it must be either passive or you need an external bias-T. The LEA's can provide up to 50mA (so no Zephyr!). If you want to step up your game and get even better stability, take one of the LEA based GPSDOs (like the Star4 mentioned above). 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.
[time-nuts] Symmetricom TimeSource 2500
Reading the recent discussion about GPS receivers for a Stratum 1 NTP server caused me to reflect on the Symmetricom TimeSource 2500 I have been using for years as a GPS-based frequency reference. I only turn this on for a couple of days when it is likely I will need it, but am not sure if this intermittent operation really achieves stratum 1 performance. A disappointment of the 2500's architecture is that it burns an SRI PRS-10 in the background as a backup in case of the loss of GPS. This seems wasteful to me as the operating life of the PRS-10 units is not unlimited. I suppose the PRS-10 could be disabled, but this would require some simulation circuitry as the 2500 monitors the PRS-10 and goes into a fault condition if the expected PRS-10 presence is absent. Certainly others have utilized these units for such use. Has anyone performed a detailed evaluation of the 2500 units in intermittent service? Bruce hunter, KG6OJI ___ 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] SI5328
Hoi Bert, On Mon, 22 Jan 2018 06:34:42 -0500 ew via time-nuts wrote: > In my opinion the SI 5328 is worth looking at for time nut application, like > offset frequency. My problem is solder ability. Does any one know a source > for an evaluation board or as an alternative a source that would do a small > volume assembly? As others have written, an eval board is available. There are many small volume assmebly houses available. But the problem is that you will have setup costs in the order of at least 100-300€, even if you go to China. So, producing lots of less than 10 is not economical, probably should aim for 100. 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Hi It is doubtful that the pc board has an RS-232 to TTL converter onboard. The module it’s self “talks” TTL levels rather than RS-232 levels. RS-232 to TTL adapters are dirt cheap and easy to find on eBay. Make sure you get one that has control lines along with the basic RX and TX functions. (You need to buffer the PPS signal). They also allow you to put in a “pulse stretcher” on the PPS if the default is to short for your computer. There is no value in a “timing” GPS vs a “normal” GPS for NTP. As long as you have a PPS output, you are good to go. As noted elsewhere, something like the more modern M8 series is just as cheap and will do a better job. Simply get any of the modules and an adapter. Hook them up and move on. Total cost should come in < $30 delivered. There are tons and tons of details on how do do all this in the archives. Bob > On Jan 22, 2018, at 10:38 AM, Paride Legovini via time-nuts > wrote: > > Dear fellow nuts, > > I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm > looking for a good and possibly affordable timing GPS receiver. > > As far as I can tell there are a few common options. One is the Trimble > Resolution T (or SMT), that should be good and proven. The major > annoyance is converting the 3.3V TTL serial logic-level to RS232, but > should be doable with a MAX3232 and a few capacitors. > > Another option is this UBLOX LEA-5T: > > https://www.ebay.it/itm/291769145465 > > The seller advertises an RS232 output pin, but I'm not sure it's > actually available, and I'd need at least lines, one for the NMEA > strings and one for the 1PPS signal. So, even if a RS232 TX pin is > actually there, it is probably not enough to build a good reference > clock, and I'd still need to convert some TTL levels to RS232... > > Does anybody have experience with this receiver? > How does it compare to the Resolution T/SMT? > > Another option is the Trimble Thunderbolt. This seems to do exactly what > I need, but it costs at least ten times more than the other modules. > Beside coming with a ready to use RS232 port and a nice case, does it > have other advantages? > > Am I overlooking something or missing interesting options? > > Cheers, > > Paride IZ3SUS > ___ > 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Why not consider a more recent current UBlox module? e.g. the M8T https://www.u-blox.com/en/product/neolea-m8t-series A quick internet search will find several suppliers of ready made boards/modules... On 22/01/2018 15:38, Paride Legovini via time-nuts wrote: > Dear fellow nuts, > > I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm > looking for a good and possibly affordable timing GPS receiver. > > As far as I can tell there are a few common options. One is the Trimble > Resolution T (or SMT), that should be good and proven. The major > annoyance is converting the 3.3V TTL serial logic-level to RS232, but > should be doable with a MAX3232 and a few capacitors. > > Another option is this UBLOX LEA-5T: > > https://www.ebay.it/itm/291769145465 > > The seller advertises an RS232 output pin, but I'm not sure it's > actually available, and I'd need at least lines, one for the NMEA > strings and one for the 1PPS signal. So, even if a RS232 TX pin is > actually there, it is probably not enough to build a good reference > clock, and I'd still need to convert some TTL levels to RS232... > > Does anybody have experience with this receiver? > How does it compare to the Resolution T/SMT? > > Another option is the Trimble Thunderbolt. This seems to do exactly what > I need, but it costs at least ten times more than the other modules. > Beside coming with a ready to use RS232 port and a nice case, does it > have other advantages? > > Am I overlooking something or missing interesting options? > > Cheers, > > Paride IZ3SUS > ___ > 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. > -- Stephen Tompsett ___ 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Paride The LEA-5T differs from other devices only that it has saw tooth information that can be used for correction or in a loop' I did a board and have one with variable delay using the 5T. Looking at the picture I do not even see an output for that information. Any later standard $10 module will be as good or better because he mentions 15 ns. What do you need and please also look at what GPS is able to do without ionospheric correction Bert In a message dated 1/22/2018 11:07:52 AM Eastern Standard Time, time-nuts@febo.com writes: Dear fellow nuts, I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm looking for a good and possibly affordable timing GPS receiver. As far as I can tell there are a few common options. One is the Trimble Resolution T (or SMT), that should be good and proven. The major annoyance is converting the 3.3V TTL serial logic-level to RS232, but should be doable with a MAX3232 and a few capacitors. Another option is this UBLOX LEA-5T: https://www.ebay.it/itm/291769145465 The seller advertises an RS232 output pin, but I'm not sure it's actually available, and I'd need at least lines, one for the NMEA strings and one for the 1PPS signal. So, even if a RS232 TX pin is actually there, it is probably not enough to build a good reference clock, and I'd still need to convert some TTL levels to RS232... Does anybody have experience with this receiver? How does it compare to the Resolution T/SMT? Another option is the Trimble Thunderbolt. This seems to do exactly what I need, but it costs at least ten times more than the other modules. Beside coming with a ready to use RS232 port and a nice case, does it have other advantages? Am I overlooking something or missing interesting options? Cheers, Paride IZ3SUS ___ 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] Suggestion for a timing GPS receiver (Trimble / Ublox / other?)
Dear fellow nuts, I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm looking for a good and possibly affordable timing GPS receiver. As far as I can tell there are a few common options. One is the Trimble Resolution T (or SMT), that should be good and proven. The major annoyance is converting the 3.3V TTL serial logic-level to RS232, but should be doable with a MAX3232 and a few capacitors. Another option is this UBLOX LEA-5T: https://www.ebay.it/itm/291769145465 The seller advertises an RS232 output pin, but I'm not sure it's actually available, and I'd need at least lines, one for the NMEA strings and one for the 1PPS signal. So, even if a RS232 TX pin is actually there, it is probably not enough to build a good reference clock, and I'd still need to convert some TTL levels to RS232... Does anybody have experience with this receiver? How does it compare to the Resolution T/SMT? Another option is the Trimble Thunderbolt. This seems to do exactly what I need, but it costs at least ten times more than the other modules. Beside coming with a ready to use RS232 port and a nice case, does it have other advantages? Am I overlooking something or missing interesting options? Cheers, Paride IZ3SUS ___ 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] SI5328
It might be possible to hand solder the 36-pin 0.5mm pitch QFN to this Schmartboard product: http://schmartboard.com/schmartboard-ez-qfn-36-pins-5mm-pitch-32-pins-65mm-pitch-2-x-2-grid-202-0043-01/ One question is would the die attach pad, which apparently needs grounding, get enough heat sinking. Bob L. > Sent: Monday, January 22, 2018 at 6:34 AM > From: "ew via time-nuts" > To: time-nuts@febo.com > Subject: [time-nuts] SI5328 > > In my opinion the SI 5328 is worth looking at for time nut application, like > offset frequency. My problem is solder ability. Does any one know a source > for an evaluation board or as an alternative a source that would do a small > volume assembly? > > Bert Kehren > ___ > 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] SI5328
On Mon, Jan 22, 2018 at 4:34 AM, ew via time-nuts wrote: > In my opinion the SI 5328 is worth looking at for time nut application, > like offset frequency. My problem is solder ability. Does any one know a > source for an evaluation board or as an alternative a source that would do > a small volume assembly? > > Bert Kehren > There is a development board. It is about $200. Search for SI5328-EVB from the usual places. https://octopart.com/search?q=si5328-evb&start=0 You can download the support software and try it out ahead of time from here: https://www.silabs.com/products/development-tools/timing/clock/si5328-evb-development-kit There have been several discussions about it as part of Leo Bodanar's GPSDOs. Search the recent archives of this list: https://www.mail-archive.com/search?l=time-nuts%40febo.com&q=si5328 Mark ___ 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] SI5328
Hello, here you can find the source of the development board with the Silicon price and the neccessary software package: https://www.silabs.com/products/development-tools/timing/clock/si5328-evb-development-kit - Chris Am 22.01.2018 um 12:34 schrieb ew via time-nuts: In my opinion the SI 5328 is worth looking at for time nut application, like offset frequency. My problem is solder ability. Does any one know a source for an evaluation board or as an alternative a source that would do a small volume assembly? Bert Kehren ___ 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] SI5328
Bert, please look at the following manual: https://www.silabs.com/documents/public/user-guides/Si5328EVB.pdf - Chris Am 22.01.2018 um 12:34 schrieb ew via time-nuts: In my opinion the SI 5328 is worth looking at for time nut application, like offset frequency. My problem is solder ability. Does any one know a source for an evaluation board or as an alternative a source that would do a small volume assembly? Bert Kehren ___ 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] SI5328
On Mon, January 22, 2018 6:42 am, Hal Murray wrote: > Does anybody know what's in the DSPLL box? Basically a PLL implemented with some kind of DDS for the VCO and DSP for the loop filter. https://www.silabs.com/documents/public/white-papers/Silicon-Labs-Next-Generation-DSPLL-Technology-White-Paper---June-2015.pdf The DSP loop filter gives a really wide range of loop bandwidth, down to fractional Hz for some parts. Using a DDS for the VCO gives a lot of flexibility in output frequency selection, but means that there can be problems with spurs. Part of the SiLabs secret sauce is supposed to reduce spurs compared to a simpler NCO implementation, but I don't think you can eliminate spurs entirely with any kind of DDS based design. -- Chris Caudle ___ 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] SI5328
Does anybody know what's in the DSPLL box? It may be in the data sheet(s), but I haven't found it. -- 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.
[time-nuts] SI5328
In my opinion the SI 5328 is worth looking at for time nut application, like offset frequency. My problem is solder ability. Does any one know a source for an evaluation board or as an alternative a source that would do a small volume assembly? Bert Kehren ___ 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.
