Re: [time-nuts] help with initial setup for Motorola M12+T GPS? is my board dead?
Looking at your pictures on Picasa, I can see that the backup battery is mounted upside down. I would at least turn this over and check again. Stijn Op 05-03-11 08:54, John Beale schreef: I just received my first real piece of time hardware, a M12+T timing GPS. At least, that's what it's supposed to be, it doesn't actually have any label saying so. I got it online from this seller: http://www.ioffer.com/i/Motorola-ONCORE-M12+T-timing-gps-receiver-1pps-100hz-105387652 The board I received looks like this: https://picasaweb.google.com/bealevideo/GPS#5580118907079326290 I got the 2x5 0.05 connector, built a 3.0V power supply, and hooked up the serial lines to a FTDI USB-to-serial (3.3V logic level) board, and am trying to talk Motorola Binary at 9600 baud to it using WinOncore12. I tried the setup receiver wizard, the GPS self-test, and uploading an almanac. My scope shows the serial data from the PC going into the board, but no signals ever come out. The TX line out of the board just sits quietly at +3V. Is there anything obvious I should be trying? Thanks for any help! ___ 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] help with initial setup for Motorola M12+T GPS? is my board dead?
On 3/4/2011 11:54 PM, John Beale wrote: The TX line out of the board just sits quietly at +3V. Is there anything obvious I should be trying? Er.. nevermind. It seems that swapping TX and RX helped. Sigh. --- COPYRIGHT 1991-2000 MOTOROLA INC. SFTW P/N # 61-G10002A SOFTWARE VER # 1 SOFTWARE REV # 3 SOFTWARE DATE Mar 13 2000 MODEL #P183T12N12 HWDR P/N # 1 SERIAL # P0171Z MANUFACTUR DATE 1J12 ___ 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] pulling oscillators
Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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] pulling oscillators
A crystal is a high Q circuit. You can't pull them much. I think your first idea about yanking the crystal and just driving the pin is a better idea. If the part has a shutdown feature, it would pay to determine the state of the crystal input pins when in the shutdown mode. -Original Message- From: Don Latham d...@montana.com Sender: time-nuts-boun...@febo.com Date: Sat, 5 Mar 2011 02:06:18 To: time nutstime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] pulling oscillators Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] pulling oscillators
Capacitively couple a Varactor (or back biased diode) to the circuit and vary the diode bias to tune. -John Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] pulling oscillators
I might ask the question how much pulling are you looking to do??? Regards On Sat, Mar 5, 2011 at 5:09 AM, J. Forster j...@quik.com wrote: Capacitively couple a Varactor (or back biased diode) to the circuit and vary the diode bias to tune. -John Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] pulling oscillators
paul swed wrote: I might ask the question how much pulling are you looking to do??? Regards Yes, your request is meaningless without this number. Having said that, you have 2 strikes against you. Trying to pull an oscillator that wasn't designed to be pulled is a problem. Secondly, the circuit you described works in so called parallel resonant mode. For optimum pullability, you want series resonant mode. Do yourself a favor, now that inexpensive VCXO's are available, patch in one of those. 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.
Re: [time-nuts] pulling oscillators
Don, if you have a reference oscillator of the right frequency, what's the the purpose of trying to pull a CMOS oscillator to the same frequency, rather than just using the reference frequency? Please be more specific on whant your requirements are. Adrian Don Latham schrieb: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don ___ 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] pulling oscillators
Hi Don, I wrote a design idea about designing that circuit in EDN in 2003. Search google for Jackson Vcxo Not that hard to do if you can add a number of passive components to your pcb. Bye, Said Sent from my iPad On Mar 5, 2011, at 1:06, Don Latham d...@montana.com wrote: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] pulling oscillators
The crystal oscillators are reference oscillators in 2 meter ham radios. I wanted to make the least perturbation in the radio, hence pulling instead of simply introducing the correct reference. I will be using a reference of the nominal frequency the radio should have, so really should not need to pull more than a few ppm if that? also not woried about the phase noise, either. Will derive the driving signal from my gps 10 mhz or from one of my FEI Rb devices. I need the accurate frequencies, or at least I think I do, because the 2 meter radio will drive a transverter to 2.4 GHz moonbounce. Sorry about not knowing how far I need to pull, or the specs of what's there. I suspect there has been some drift since the radio was made. Putting in a vcxo or varactor simply puts off the problem, as then I have to monitor that frequency and control it. I could cobble in a little tuning cap, but still would be left with a pretty temp sensitive reference. Hope the question is clearer, and thanks to all who replied! Don Adrian Don, if you have a reference oscillator of the right frequency, what's the the purpose of trying to pull a CMOS oscillator to the same frequency, rather than just using the reference frequency? Please be more specific on whant your requirements are. Adrian Don Latham schrieb: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don ___ 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. R. Bacon 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] pulling oscillators
Don If you search the web, someone used inductive coupling to the inductor in the oscillator ckt of a 706. I don't recall if it had the high precision osc in it. they were using the rig for satellite work. good luck Rix Seacord K2AVP eseac...@verizon.net 845-628-0892 914-262-9186 On 3/5/2011 2:52 PM, Don Latham wrote: The crystal oscillators are reference oscillators in 2 meter ham radios. I wanted to make the least perturbation in the radio, hence pulling instead of simply introducing the correct reference. I will be using a reference of the nominal frequency the radio should have, so really should not need to pull more than a few ppm if that? also not woried about the phase noise, either. Will derive the driving signal from my gps 10 mhz or from one of my FEI Rb devices. I need the accurate frequencies, or at least I think I do, because the 2 meter radio will drive a transverter to 2.4 GHz moonbounce. Sorry about not knowing how far I need to pull, or the specs of what's there. I suspect there has been some drift since the radio was made. Putting in a vcxo or varactor simply puts off the problem, as then I have to monitorthat frequency and control it. I could cobble in a little tuning cap, but still would be left with a pretty temp sensitive reference. Hope the question is clearer, and thanks to all who replied! Don Adrian Don, if you have a reference oscillator of the right frequency, what's the the purpose of trying to pull a CMOS oscillator to the same frequency, rather than just using the reference frequency? Please be more specific on whant your requirements are. Adrian Don Latham schrieb: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don ___ 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] difference between Oncore M12 and M12+T (useful when buying online)
In case anyone else is shopping online for a used Motorola Oncore M12+T timing GPS, it's probably useful to know what I just learned: Some online sellers offering M12+T 100 pps GPS may instead send you a M12 Navigation (non-timing) GPS. The differences: Motorola Oncore M12 Navigation GPS: --- * Supports Motorola Binary and NMEA output * does not have 100 Hz output * does not have TRAIM (Timing Receiver Autonomous Integrity Monitor) * does not have sawtooth correction output * 1 PPS 500 ns timing crystal nearest MMCX antenna connector is two-lead can style with bent leads for surface mounting example p/n label: P183T12N12 (final N = Navigation?) photos: http://www.wa5rrn.com/GPS%20Other/Motorola%20M12/m12.pdf https://picasaweb.google.com/bealevideo/GPS#5580118907079326290 Motorola Oncore M12+T Timing GPS: --- * Supports Motorola Binary output only * 1 Hz or 100 Hz output selectable * TRAIM (Timing Receiver Autonomous Integrity Monitor) * sawtooth correction (clock granularity) message available * 1 pps 2nS 1 Sigma, 6nS 6 Sigma (using sawtooth correction message) * 1 pps 10nS 1 Sigma, 20nS 6 Sigma (without correction) smaller leadless surface-mount crystals example p/n label: P283T12T17(final T = Timing?) photos: http://www.wa5rrn.com/GPS%20Other/Motorola%20M12/m12plusbrochure.pdf http://cgi.ebay.co.uk/ws/eBayISAPI.dll?VISuperSizeitem=290308535362 ___ 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] Arduino Thunderbolt GPS
Thanks Didier, lots of useful information on there! On Thu, Mar 3, 2011 at 4:30 PM, Didier Juges shali...@gmail.com wrote: James, The data stream is not that difficult to decode. You can look at the source code for my GPSMonitor project: http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:gps_monitor Didier KO4BB On Tue, Mar 1, 2011 at 7:37 PM, James Fournier ja...@jfits.ca wrote: Hello All, Has any one managed to use an Arduino to read the RS232 output of a Trimble Thunderbolt? If so what libraries did you use? -- Best Regards, James ___ 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. -- Best Regards, James ___ 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] difference between Oncore M12 and M12+T (useful when buying online)
Indeed its not easy to tell whats, what either until you paid for it. I purchased from Fluke.I and my modules is a M12 +. But who knows maybe I was just lucky. Regards Paul WB8TSL On Sat, Mar 5, 2011 at 5:15 PM, John Beale be...@bealecorner.com wrote: In case anyone else is shopping online for a used Motorola Oncore M12+T timing GPS, it's probably useful to know what I just learned: Some online sellers offering M12+T 100 pps GPS may instead send you a M12 Navigation (non-timing) GPS. The differences: Motorola Oncore M12 Navigation GPS: --- * Supports Motorola Binary and NMEA output * does not have 100 Hz output * does not have TRAIM (Timing Receiver Autonomous Integrity Monitor) * does not have sawtooth correction output * 1 PPS 500 ns timing crystal nearest MMCX antenna connector is two-lead can style with bent leads for surface mounting example p/n label: P183T12N12 (final N = Navigation?) photos: http://www.wa5rrn.com/GPS%20Other/Motorola%20M12/m12.pdf https://picasaweb.google.com/bealevideo/GPS#5580118907079326290 Motorola Oncore M12+T Timing GPS: --- * Supports Motorola Binary output only * 1 Hz or 100 Hz output selectable * TRAIM (Timing Receiver Autonomous Integrity Monitor) * sawtooth correction (clock granularity) message available * 1 pps 2nS 1 Sigma, 6nS 6 Sigma (using sawtooth correction message) * 1 pps 10nS 1 Sigma, 20nS 6 Sigma (without correction) smaller leadless surface-mount crystals example p/n label: P283T12T17(final T = Timing?) photos: http://www.wa5rrn.com/GPS%20Other/Motorola%20M12/m12plusbrochure.pdf http://cgi.ebay.co.uk/ws/eBayISAPI.dll?VISuperSizeitem=290308535362 ___ 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] difference between Oncore M12 and M12+T (useful when buying o...
In a message dated 05/03/2011 22:16:39 GMT Standard Time, be...@bealecorner.com writes: In case anyone else is shopping online for a used Motorola Oncore M12+T timing GPS, it's probably useful to know what I just learned: Some online sellers offering M12+T 100 pps GPS may instead send you a M12 Navigation (non-timing) GPS. The differences: Hi John I'm sorry to hear you came unstuck with your purchase, as Paul commented it's difficult to know what you're getting at times when buying online, especially from China, but Bob (fluke.l) is well known here and one of the more dependable suppliers. Amongst other things, I've bought two M12+ modules from him, similar auction to the one you provided a link for, and both were timing versions as expected. A further word of warning though, there are also two versions of the M12+, one for positioning and one for timing, and the M12+ brochure you've linked to at _http://www.wa5rrn.com/GPS%20Other/Motorola%20M12/m12plusbrochure.pdf_ (http://www.wa5rrn.com/GPS%20Other/Motorola%20M12/m12plusbrochure.pdf) has the spec for the positioning version, note that the timing accuracy is indicated as less than 500nS as you mentioned for the M12M. There's a data pack available of assorted M12 and M12+ files, I've added the M12+ manual to that which includes specs for both positioning and timing versions, and will email it direct after sending this. It's just under 7MB so should be ok for most ISPs but if it doesn't arrive, or if there's any problems, let me know and I'll try again. regards Nigel GM8PZR ___ 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] difference between Oncore M12 and M12+T (useful when buying o...
Just for reference, these are the variant numbers I have for the M12+... Timer --No Battery - P273T12T1x Timer - With Battery -- P283T12T1x Navigation -- No Battery - P273T12N1x Navigation -- With Battery -- P283T12N1x regards Nigel GM8PZR ___ 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] oscillator pulling.
Ok,OK already. all i had to do was have a look at: http://www.ko4bb.com/~bruce/InjectionLocking.html our old friend k04bb. doh! Thanks all. Don -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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] pulling oscillators
The on chip inverter is usually pretty weak and often designed to have a high impedance output. When intended as a transconductance amp, the output mostly looks like a current source (hence the high impedance). Some oscillators use a resistor outside the IC in series with the inverter output to help control maximum crystal drive level, reduce chances of overtone oscillation, or in hopes of improving the overall Q. If the series resistor is present, there are three places you can inject your signal: at the inverter output, between the resistor and crystal and at the inverter input. With a weak on-chip inverter, you can overdrive the inverter output over a large frequency range. Phase noise could be an issue, but was not a problem with my application when I've used this method. Be careful not to exceed the voltage range of the chip. If you stay close to the crystal resonate frequency, injecting the pulling signal in between the series resistor and crystal can be similar to injecting at the inverter input. But it's not a good place to inject the signal as you get further from the frequency the loaded crystal wants to sing at. Injecting at the input of the inverter has worked OK for me. The further you go off frequency, the larger signal you need. If you want to drive a ways off, the load capacitor and the crystal shunt capacitance in series with the other load capacitor just become a capacitive load. If the resistor is not present outside the IC, then the first two cases become the same. You may be able to overdrive the inverter output, but have to also consider the load of the crystal and crystal load caps. If you stay close enough in frequency that the crystal is singing along with your source, than I'd guess the phase noise should be on the order of the un-pulled oscillator or the pulling source (whichever is worse). (And in the cases where I pulled way off [20 %], the crystal went pretty quiet and I didn't notice any phase noise [although I wasn't really looking for phase noise].) Good luck, Stan -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham Sent: Saturday, March 05, 2011 11:52 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] pulling oscillators The crystal oscillators are reference oscillators in 2 meter ham radios. I wanted to make the least perturbation in the radio, hence pulling instead of simply introducing the correct reference. I will be using a reference of the nominal frequency the radio should have, so really should not need to pull more than a few ppm if that? also not woried about the phase noise, either. Will derive the driving signal from my gps 10 mhz or from one of my FEI Rb devices. I need the accurate frequencies, or at least I think I do, because the 2 meter radio will drive a transverter to 2.4 GHz moonbounce. Sorry about not knowing how far I need to pull, or the specs of what's there. I suspect there has been some drift since the radio was made. Putting in a vcxo or varactor simply puts off the problem, as then I have to monitor that frequency and control it. I could cobble in a little tuning cap, but still would be left with a pretty temp sensitive reference. Hope the question is clearer, and thanks to all who replied! Don Adrian Don, if you have a reference oscillator of the right frequency, what's the the purpose of trying to pull a CMOS oscillator to the same frequency, rather than just using the reference frequency? Please be more specific on whant your requirements are. Adrian Don Latham schrieb: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don ___ 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. R. Bacon 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
Re: [time-nuts] pulling oscillators
Thanks Stan. I think I'll try it. I thought I'd seen something before, indeed there was a flurry of injection locking on time-nuts just last month. I simply forgot the right terminology! The R is built into the chip in both radios. The Icom 260A has a 5.12 MHz xtal and does have a trim cap. The Yaesu 290L has a 5.76 MHz reference, and no trim cap. I'll try the Icom first, I think. It'll take a while... Don Stan Searing The on chip inverter is usually pretty weak and often designed to have a high impedance output. When intended as a transconductance amp, the output mostly looks like a current source (hence the high impedance). Some oscillators use a resistor outside the IC in series with the inverter output to help control maximum crystal drive level, reduce chances of overtone oscillation, or in hopes of improving the overall Q. If the series resistor is present, there are three places you can inject your signal: at the inverter output, between the resistor and crystal and at the inverter input. With a weak on-chip inverter, you can overdrive the inverter output over a large frequency range. Phase noise could be an issue, but was not a problem with my application when I've used this method. Be careful not to exceed the voltage range of the chip. If you stay close to the crystal resonate frequency, injecting the pulling signal in between the series resistor and crystal can be similar to injecting at the inverter input. But it's not a good place to inject the signal as you get further from the frequency the loaded crystal wants to sing at. Injecting at the input of the inverter has worked OK for me. The further you go off frequency, the larger signal you need. If you want to drive a ways off, the load capacitor and the crystal shunt capacitance in series with the other load capacitor just become a capacitive load. If the resistor is not present outside the IC, then the first two cases become the same. You may be able to overdrive the inverter output, but have to also consider the load of the crystal and crystal load caps. If you stay close enough in frequency that the crystal is singing along with your source, than I'd guess the phase noise should be on the order of the un-pulled oscillator or the pulling source (whichever is worse). (And in the cases where I pulled way off [20 %], the crystal went pretty quiet and I didn't notice any phase noise [although I wasn't really looking for phase noise].) Good luck, Stan -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham Sent: Saturday, March 05, 2011 11:52 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] pulling oscillators The crystal oscillators are reference oscillators in 2 meter ham radios. I wanted to make the least perturbation in the radio, hence pulling instead of simply introducing the correct reference. I will be using a reference of the nominal frequency the radio should have, so really should not need to pull more than a few ppm if that? also not woried about the phase noise, either. Will derive the driving signal from my gps 10 mhz or from one of my FEI Rb devices. I need the accurate frequencies, or at least I think I do, because the 2 meter radio will drive a transverter to 2.4 GHz moonbounce. Sorry about not knowing how far I need to pull, or the specs of what's there. I suspect there has been some drift since the radio was made. Putting in a vcxo or varactor simply puts off the problem, as then I have to monitor that frequency and control it. I could cobble in a little tuning cap, but still would be left with a pretty temp sensitive reference. Hope the question is clearer, and thanks to all who replied! Don Adrian Don, if you have a reference oscillator of the right frequency, what's the the purpose of trying to pull a CMOS oscillator to the same frequency, rather than just using the reference frequency? Please be more specific on whant your requirements are. Adrian Don Latham schrieb: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don ___ 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
[time-nuts] found another oldie Trek 8821
Uses a Magnavox GPS Engine https://picasaweb.google.com/111617808980322733757/Trek_8821# Someone have or can point me to a manual ? and someone know what it wants for an antenna ? thanks -pete ___ 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] pulling oscillators
The resistor is needed because the crystal doesn't conduct DC. If a DC path isn't present, then the inverter will not self-bias. The inverter is weak, but this is all kind of relative. The channel length is made long to minimize the current of the inverter since it sits in the linear part of the transfer function. But the inverter is still plenty strong. If the resistor is internal, you can still jam the signal. It just means power will be lost in the resistor. On 3/5/2011 4:58 PM, Stan Searing wrote: The on chip inverter is usually pretty weak and often designed to have a high impedance output. When intended as a transconductance amp, the output mostly looks like a current source (hence the high impedance). Some oscillators use a resistor outside the IC in series with the inverter output to help control maximum crystal drive level, reduce chances of overtone oscillation, or in hopes of improving the overall Q. If the series resistor is present, there are three places you can inject your signal: at the inverter output, between the resistor and crystal and at the inverter input. With a weak on-chip inverter, you can overdrive the inverter output over a large frequency range. Phase noise could be an issue, but was not a problem with my application when I've used this method. Be careful not to exceed the voltage range of the chip. If you stay close to the crystal resonate frequency, injecting the pulling signal in between the series resistor and crystal can be similar to injecting at the inverter input. But it's not a good place to inject the signal as you get further from the frequency the loaded crystal wants to sing at. Injecting at the input of the inverter has worked OK for me. The further you go off frequency, the larger signal you need. If you want to drive a ways off, the load capacitor and the crystal shunt capacitance in series with the other load capacitor just become a capacitive load. If the resistor is not present outside the IC, then the first two cases become the same. You may be able to overdrive the inverter output, but have to also consider the load of the crystal and crystal load caps. If you stay close enough in frequency that the crystal is singing along with your source, than I'd guess the phase noise should be on the order of the un-pulled oscillator or the pulling source (whichever is worse). (And in the cases where I pulled way off [20 %], the crystal went pretty quiet and I didn't notice any phase noise [although I wasn't really looking for phase noise].) Good luck, Stan -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham Sent: Saturday, March 05, 2011 11:52 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] pulling oscillators The crystal oscillators are reference oscillators in 2 meter ham radios. I wanted to make the least perturbation in the radio, hence pulling instead of simply introducing the correct reference. I will be using a reference of the nominal frequency the radio should have, so really should not need to pull more than a few ppm if that? also not woried about the phase noise, either. Will derive the driving signal from my gps 10 mhz or from one of my FEI Rb devices. I need the accurate frequencies, or at least I think I do, because the 2 meter radio will drive a transverter to 2.4 GHz moonbounce. Sorry about not knowing how far I need to pull, or the specs of what's there. I suspect there has been some drift since the radio was made. Putting in a vcxo or varactor simply puts off the problem, as then I have to monitorthat frequency and control it. I could cobble in a little tuning cap, but still would be left with a pretty temp sensitive reference. Hope the question is clearer, and thanks to all who replied! Don Adrian Don, if you have a reference oscillator of the right frequency, what's the the purpose of trying to pull a CMOS oscillator to the same frequency, rather than just using the reference frequency? Please be more specific on whant your requirements are. Adrian Don Latham schrieb: Hello all: I've developed a need for pulling crystal oscillators built in to pll circuits. These are cmos, and have the common style oscillator circuit built in. The crystal is across an inverter in the chip, and there is a small cap between each end of the crystal and ground. The chips are pll's in radio transceivers, early at that. I could carefully remove the crystals and caps, simply driving the non-inverting input on the chip with the reference, but I would rather simply tack on a very small cap and pull the crystal oscillator with an external reference signal of the right frequency. Anyone out there tried this? Thanks Don ___ 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] found another oldie Trek 8821
In a message dated 06/03/2011 02:43:53 GMT Standard Time, p...@petelancashire.com writes: Uses a Magnavox GPS Engine https://picasaweb.google.com/111617808980322733757/Trek_8821# Someone have or can point me to a manual ? and someone know what it wants for an antenna ? -- If you mean Trak I may have a manual, need to check in the morning now, but in the meantime the Trak 8820 manual is here... _http://www.to-way.com/tf.html_ (http://www.to-way.com/tf.html) regards Nigel GM8PZR ___ 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] found another oldie Trek 8821
yes .. read before hitting send .. read before hitting send ... (repeat 100 times) -pete On Sat, Mar 5, 2011 at 6:54 PM, gandal...@aol.com wrote: In a message dated 06/03/2011 02:43:53 GMT Standard Time, p...@petelancashire.com writes: Uses a Magnavox GPS Engine https://picasaweb.google.com/111617808980322733757/Trek_8821# Someone have or can point me to a manual ? and someone know what it wants for an antenna ? -- If you mean Trak I may have a manual, need to check in the morning now, but in the meantime the Trak 8820 manual is here... _http://www.to-way.com/tf.html_ (http://www.to-way.com/tf.html) regards Nigel GM8PZR ___ 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.
