Re: [time-nuts] 510 doubler
I had forgotten about one quite promising candidate -- the THAT300 matched monolithic quad. I have some of those, too. I'll put it on the to-do list. To the best of my knowledge, they do not have reverse protection diodes across the B-E junctions (I've never had any reason to check). Best regards, Charles I wrote: Once upon a time, Motorola made monolithic quad BJTs -- but I'm not aware of any matched quads similar to 2Ns at this time. Gerhard replied: There still are MAT04 HFA3046-3096-3127-3128 if duals are enough: SSM2220 MAT12 also mat02, mat03, maybe SSM2110 [probably meant SSM2210? also, there is SSM2212] I had thought of these, but unfortunately, all of the AD parts (MAT and SSM) -- which otherwise look promising -- have reverse diodes across the B-E junctions, which rules them out as diode substitutes. The HFA parts are small-geometry, ultra-high frequency devices (Ft = 8GHz for the NPNs), not at all like 2Ns. It is doubtful they would have the low flicker noise of s. They are monolithic, so they should be pretty well matched, but only the differential pair in the 3046 is actually specified for matching -- and you couldn't use both of the diff pair in a ring structure because of the common cathodes. The 3127 would be the part to try. I have some, so maybe I'll try them (but I'm not hopeful). Best regards, Charles ___ 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] SR620 question
Simply pasting the link did not work, but it was close enough :-) The links that include an IP address (like 81.226.54.139 below) only work until midnight EST, then they are cleared. It is easy enough (but not necessarily intuitive) to go to the manuals page and search again for the document. I am trying to come up with a scheme that will create a permanent link. Bear with me a little longer... Didier KO4BB On January 28, 2015 7:41:59 AM CST, Gerhard Hoffmann dk...@arcor.de wrote: Am 28.01.2015 um 00:23 schrieb Magnus Danielson: It locks it up with a PLL. See page 9 in PDF below, smack in the middle is the input circuit and PLL. This page also gives you all the hints of how to wire in a better oscillator if you wish. 2 I have seen that the manual has a parts list and references the circuit diagrams, but they are not included in the pdf. Are the circuits somewhere out there? http://www.ko4bb.com/manuals/81.226.54.139/SR620_Universal_Time_Interval_Counter_Schematics.pdf Simply pasting the link did not work, but it was close enough :-) Thanks, also to Charles! After Bob's comment, I have ordered it with the oven. Should be here in .de in a good week. My 5370A has become so unreliable that it needs replacement. What issues do you see? Erratic blinking of the display, probably column drivers, but not only, bad switches that seem to stick now then.. For some time, it was enough to remove and re-insert the boards, but no more. I don't have the time now to look deeply into it. All would not be lost. It has a nice 10811. 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. -- 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] Clock stability and its measures
Hi, I have been tasked to give a talk on clock stability and its measures next thursday. Most of the stuff is pretty clear (and the rest can be easily looked up in Rubiolas book, various app notes and papers). But I would like to make sure I did not forget anything important. The types of stability measures we have are: * deviations * Allan deviation * modified Allan deviation * time deviation * Hadamard deviation * noise spectrum * single sided power spectral density * jitter * cycle-to-cycle jitter * period jitter * time interval error Are there any other measures? Or anything important I should make sure to mention? Also, if someone has a presentation where I could steal some stuff from, I would appreciate that as well. 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] Clock stability and its measures
Hi Attila, What is your crowd? For telecom or other data-recovery (where the jitter thread is relevant), you may want to also cover MTIE for instance. Also, you want to speak about wander. I'll toss you my slides from my 5 h lecture this Monday. The audience was a bit different, but maybe you get some ideas and I can explain some of the points. Cheers, Magnus On 01/29/2015 03:17 PM, Attila Kinali wrote: Hi, I have been tasked to give a talk on clock stability and its measures next thursday. Most of the stuff is pretty clear (and the rest can be easily looked up in Rubiolas book, various app notes and papers). But I would like to make sure I did not forget anything important. The types of stability measures we have are: * deviations * Allan deviation * modified Allan deviation * time deviation * Hadamard deviation * noise spectrum * single sided power spectral density * jitter * cycle-to-cycle jitter * period jitter * time interval error Are there any other measures? Or anything important I should make sure to mention? Also, if someone has a presentation where I could steal some stuff from, I would appreciate that as well. Attila Kinali ___ 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 stability and its measures
You might, depending upon the audience, point out the advantages of heterodyne in the comparison of two RF signals. This, as you know, relieves the burden of precision on the measurement equipment by the heterodyne ratio. Mike -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: Thursday, January 29, 2015 9:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Clock stability and its measures Hi, I have been tasked to give a talk on clock stability and its measures next thursday. Most of the stuff is pretty clear (and the rest can be easily looked up in Rubiolas book, various app notes and papers). But I would like to make sure I did not forget anything important. The types of stability measures we have are: * deviations * Allan deviation * modified Allan deviation * time deviation * Hadamard deviation * noise spectrum * single sided power spectral density * jitter * cycle-to-cycle jitter * period jitter * time interval error Are there any other measures? Or anything important I should make sure to mention? Also, if someone has a presentation where I could steal some stuff from, I would appreciate that as well. 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 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] Motorola Oncore M12+T Sawtooth
I've built a bunch of carrier board for the M12+T timing receiver. One thing I could not find much information about is the maximum sawtooth (which, I assume, related directly to the frequency of the receiver's internal LO). I know my particular module outputs a correction values between -15 and +15, in which case I could use a DS1023-25 delay-line chip which uses .25ns increments instead of the DS1023-100, which uses 1ns. This would give the overall circuit slightly better linearity. Problem is that the datasheet doesn't say anything about this, it just says -128..+127ns. Does anyone know if there are receiver units out there that have different LOs ? Regards, Tom ___ 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] Fwd: Symmetricom TymServe 2100-GPS currently fails with GPS offset
Tim Lister kirjoitti: Hi Esa, I am forwarding this message as I'm not subscribed to time-nuts list, just a lurker... It's good to know we're not the only ones having problems, even if there is no obvious solution. Do you think there is any hope of getting Symmetricom/Microsemi to release an updated firmware to fix this or are they most likely to turn around and say buy something made this decade... It's possible that they cannot fix this even if they wanted to do so (which I doubt) because it's kinda old product and it may be that there's no engineers anymore in the house who know this product. I afraid that only way to fix the firmware is to do itself. I have a guess that the problem is related to decoding of wrong portions of the GPS frames. So it would be possible to find where the actual command to decode UTC offset is used and change that part of the firmware. This is not easy way at all, but it's possible to do. It consumes HUGE amount of time. First thing to do is to find out what protocol is used between mainboard and GPS. Because it uses Trimble GPS module this could be TSIP (rough guess). To find it out, it's required to install a sniffer between the GPS and mainboard. TSIP protocol specification seems to be available on the Internet. Firmware modification is not easy task to do and it's also dangerous, whole unit may be permamently useless after loading the mofified firmware, with no way to load correct firmware anymore. There's also checksum mechanism to prevent corrrupt firmware and because of that the data content must match the checksum or checksum must be updated. Another (and recommended) way could be to add some simple microcontroller (Microchip PIC for example) between the GPS unit and motherboard and write own software which modifies the GPS traffic so that UTC offset will be correct again. This way also requires some study first but after the details are known the needed software for data modification should be very easy to do. I have motivation to fix this but having no time for this, at least in near future. Quick fix was to feed it with 1PPS from Thunderbolt. However it unconfortable to do this every time when leap second is coming. Also, if the power is lost it will start from January first 2015 00:00:00 and the time must be set manually each time, it does not recover automatically with PPS. That's why it would be so nice to fix this, but without any knowledge of the unit details, firmware source code or GPS protocol it will require many days to do. Best regards, -- 73s! Esa OH4KJU ___ 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] Motorola Oncore M12+T Sawtooth
google for: m12 gps sawtooth The +/- 127 comes from the range of 8 bits. /tvb (i5s) On Jan 29, 2015, at 12:44 PM, Tom Wimmenhove tom.wimmenh...@gmail.com wrote: I've built a bunch of carrier board for the M12+T timing receiver. One thing I could not find much information about is the maximum sawtooth (which, I assume, related directly to the frequency of the receiver's internal LO). I know my particular module outputs a correction values between -15 and +15, in which case I could use a DS1023-25 delay-line chip which uses .25ns increments instead of the DS1023-100, which uses 1ns. This would give the overall circuit slightly better linearity. Problem is that the datasheet doesn't say anything about this, it just says -128..+127ns. Does anyone know if there are receiver units out there that have different LOs ? Regards, Tom ___ 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] 510 doubler
On 1/28/2015 11:28 AM, Charles Steinmetz wrote: Gerhard wrote: It is a different game when you want to notch away sub/harmonics. One problem with using crystals as traps (notch filters) is that the series resistance of a crystal is several orders of magnitude higher than that of a good series-resonant LC -- generally in the 50-100 ohm range. So, although the notch is very narrow, it will not be very deep unless it is in a high-impedance circuit. For example, in a 50 ohm It is very straightforward to use LC networks to transform the impedance of the crystal to a much lower value and get around this problem. Rick Karlquist N6RK ___ 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.
