Re: [time-nuts] REF osc distribution.
Hello, I understand your remarks but so far nobody who buy these unit complain about the performances. People are using it for 5DB to 13dB 10MHz Sine wave distribution, others are using it for 1PPS distribution in TTL (O-5volt) or in TTL (0-3.3Volt). Performance are good enough for the telecom and military application we are offering the unit. The gain of the unit is 0dB (1): same output than input level and slew rate is 2KV/microsec. Each output have his own op amps. For price contact me by email luc.gau...@naelcom.com. Regards Luc -Message d'origine- De : time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] De la part de Robert Atkinson Envoyé : vendredi 7 septembre 2012 08:31 À : Discussion of precise time and frequency measurement Objet : Re: [time-nuts] REF osc distribution. Hi It may be a language issue, but the datasheet does not present this amplifier very well. I wondered about the specification for squarewave input TTL 3.3V TTL is 5V. What is the slew rate of the amplifier? It's specified to 50MHz, will it accurately reproduce a 50MHz square wave? A 1V RMS output is not going to reproduce a TTL 1PPS or 10MHz clock very well. It does state that each output is isolated and buffered. It reads as a general purpose wideband amplifier rather than one optimised for a particular timing application. Robert G8RPI From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, 6 September 2012, 20:54 Subject: Re: [time-nuts] REF osc distribution. Luc wrote: We have a product that have been specially design for these : NGA-DIS Thank you for the link. The data sheet raises a few questions: The sine wave input level is specified as 1Vrms nominal 0.5V Peak to peak. Of course, 1Vrms is ~2.8Vp-p. It is not clear what this specification means. Gain and noise are not specified, nor is isolation from output to input or from the outputs to each other. These are parameters that many buyers will want to know. Have you characterized the NGA-DIS for phase noise? That is also a parameter many buyers will want to know. Does each output have its own output amplifier, or does one amplifier drive multiple outputs through individual build-out resistors? Does the NGA-DIS use op amps, or discrete circuitry? What is the price? 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. ___ 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] REF osc distribution.
Hi It may be a language issue, but the datasheet does not present this amplifier very well. I wondered about the specification for squarewave input TTL 3.3V TTL is 5V. What is the slew rate of the amplifier? It's specified to 50MHz, will it accurately reproduce a 50MHz square wave? A 1V RMS output is not going to reproduce a TTL 1PPS or 10MHz clock very well. It does state that each output is isolated and buffered. It reads as a general purpose wideband amplifier rather than one optimised for a particular timing application. Robert G8RPI From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, 6 September 2012, 20:54 Subject: Re: [time-nuts] REF osc distribution. Luc wrote: We have a product that have been specially design for these : NGA-DIS Thank you for the link. The data sheet raises a few questions: The sine wave input level is specified as 1Vrms nominal 0.5V Peak to peak. Of course, 1Vrms is ~2.8Vp-p. It is not clear what this specification means. Gain and noise are not specified, nor is isolation from output to input or from the outputs to each other. These are parameters that many buyers will want to know. Have you characterized the NGA-DIS for phase noise? That is also a parameter many buyers will want to know. Does each output have its own output amplifier, or does one amplifier drive multiple outputs through individual build-out resistors? Does the NGA-DIS use op amps, or discrete circuitry? What is the price? 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. ___ 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] REF osc distribution.
Hello, We have a product that have been specially design for these : NGA-DIS http://naelcom.fr/app/download/5788490907/Data+sheet+NGA-DIS+V1.0.pdf Regards, Luc -Message d'origine- De : time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] De la part de Bob Camp Envoyé : mardi 4 septembre 2012 18:23 À : 'Discussion of precise time and frequency measurement' Objet : Re: [time-nuts] REF osc distribution. Hi Lots of choices: 1)do you need 1 pps distributed? 2)do you need 100 KHz, 1MHz, 5MHz (or really odd frequencies) for anything? 3)how many 10 MHz gizmos do you have? 4)Do you need / want to receive 10 MHz radio signals while distributing 10 MHz? (same question for other frequencies if you use therm). 5)What are you running the signals to? / how clean does the phase noise need to be? 6)What are you running the signals to? / how good does the short term stability need to be? 7)(same)/ how good does the isolation need to be? 8)(same)/ do you need redundancy or anything else unusual? For simple need to run a frequency counter needs, video amps are often the easy choice. For more demanding gear, you can have very complex distribution systems. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rui Martins Sent: Tuesday, September 04, 2012 9:23 AM To: time-nuts@febo.com Subject: [time-nuts] REF osc distribution. Hi, At the moment my GPSTM have 1.3e-012 in alan deviation and it's time to connect to the equipements. Which is the best way to do it? CT1EBHT Rui Jorge Martins 73! ___ 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] REF osc distribution.
What is the port to port isolation and price Sent from my iPad On Sep 6, 2012, at 2:21 AM, Gaudin Luc lgau...@naelcom.com wrote: Hello, We have a product that have been specially design for these : NGA-DIS http://naelcom.fr/app/download/5788490907/Data+sheet+NGA-DIS+V1.0.pdf Regards, Luc -Message d'origine- De : time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] De la part de Bob Camp Envoyé : mardi 4 septembre 2012 18:23 À : 'Discussion of precise time and frequency measurement' Objet : Re: [time-nuts] REF osc distribution. Hi Lots of choices: 1)do you need 1 pps distributed? 2)do you need 100 KHz, 1MHz, 5MHz (or really odd frequencies) for anything? 3)how many 10 MHz gizmos do you have? 4)Do you need / want to receive 10 MHz radio signals while distributing 10 MHz? (same question for other frequencies if you use therm). 5)What are you running the signals to? / how clean does the phase noise need to be? 6)What are you running the signals to? / how good does the short term stability need to be? 7)(same)/ how good does the isolation need to be? 8)(same)/ do you need redundancy or anything else unusual? For simple need to run a frequency counter needs, video amps are often the easy choice. For more demanding gear, you can have very complex distribution systems. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rui Martins Sent: Tuesday, September 04, 2012 9:23 AM To: time-nuts@febo.com Subject: [time-nuts] REF osc distribution. Hi, At the moment my GPSTM have 1.3e-012 in alan deviation and it's time to connect to the equipements. Which is the best way to do it? CT1EBHT Rui Jorge Martins 73! ___ 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. ___ 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] REF osc distribution.
Luc wrote: We have a product that have been specially design for these : NGA-DIS Thank you for the link. The data sheet raises a few questions: The sine wave input level is specified as 1Vrms nominal 0.5V Peak to peak. Of course, 1Vrms is ~2.8Vp-p. It is not clear what this specification means. Gain and noise are not specified, nor is isolation from output to input or from the outputs to each other. These are parameters that many buyers will want to know. Have you characterized the NGA-DIS for phase noise? That is also a parameter many buyers will want to know. Does each output have its own output amplifier, or does one amplifier drive multiple outputs through individual build-out resistors? Does the NGA-DIS use op amps, or discrete circuitry? What is the price? 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] REF osc distribution.
Bob and Paul, I have at moment 6 equipment's maximum which I want sync with 10MHZ only. The video distribution is an idea but the kit from Ve2zaz have other way but the problem is the isolation. I have 2 independent Nortel GPSTM but I don't need redundancy for the job. G3ruh and ve2zaz Kits and rubidium oscillators only for analyzing the data and compare. I will use one of them with a doubler to get 20MHZ for driving a transceiver (Crazy huh). Any ideas will be considered. Regards CT1EBH Rui Jorge Martins Proudly user of FT-ONE, FT-980, FT736R, FT726R, FT-2000 and FL-7000 73! ___ 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] REF osc distribution.
-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rui Martins Sent: 05 September 2012 15:19 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Bob and Paul, I have at moment 6 equipment's maximum which I want sync with 10MHZ only. The video distribution is an idea but the kit from Ve2zaz have other way but the problem is the isolation. I have 2 independent Nortel GPSTM but I don't need redundancy for the job. G3ruh and ve2zaz Kits and rubidium oscillators only for analyzing the data and compare. ..snip.. Rui, It might be helping if you included web links to the two kits above. Ron EI2JP ___ 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] REF osc distribution.
Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rui Martins Sent: Wednesday, September 05, 2012 10:19 AM To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Bob and Paul, I have at moment 6 equipment's maximum which I want sync with 10MHZ only. The video distribution is an idea but the kit from Ve2zaz have other way but the problem is the isolation. I have 2 independent Nortel GPSTM but I don't need redundancy for the job. G3ruh and ve2zaz Kits and rubidium oscillators only for analyzing the data and compare. I will use one of them with a doubler to get 20MHZ for driving a transceiver (Crazy huh). Any ideas will be considered. Regards CT1EBH Rui Jorge Martins Proudly user of FT-ONE, FT-980, FT736R, FT726R, FT-2000 and FL-7000 73! ___ 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] REF osc distribution.
On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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] REF osc distribution.
Hi You *can* get the job done with a CMOS inverter biased up and filtered. An op amp is likely not as good as the full bipolar approach and may be better / worse than the gate depending on exactly what you are looking at. Bob On Sep 5, 2012, at 12:59 PM, Michael Tharp g...@partiallystapled.com wrote: On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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] REF osc distribution.
I have seen that many commercial ref distribution amps are not as good as a quality low phase noise 5 or 10MHz oscillator, considering the time and resources that went into their design I think it would be difficult to design a amp capable of distributing something much cleaner then a LPRO. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 17:37:34 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi You *can* get the job done with a CMOS inverter biased up and filtered. An op amp is likely not as good as the full bipolar approach and may be better / worse than the gate depending on exactly what you are looking at. Bob On Sep 5, 2012, at 12:59 PM, Michael Tharp g...@partiallystapled.com wrote: On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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] REF osc distribution.
Hi The NIST bipolar designs can indeed do better than a good quality OCXO for short term and close in phase noise. If you have a wide band floor at -185 dbc/Hz on your OCXO they aren't quite up to that level. Bob On Sep 5, 2012, at 5:55 PM, Tom Knox act...@hotmail.com wrote: I have seen that many commercial ref distribution amps are not as good as a quality low phase noise 5 or 10MHz oscillator, considering the time and resources that went into their design I think it would be difficult to design a amp capable of distributing something much cleaner then a LPRO. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 17:37:34 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi You *can* get the job done with a CMOS inverter biased up and filtered. An op amp is likely not as good as the full bipolar approach and may be better / worse than the gate depending on exactly what you are looking at. Bob On Sep 5, 2012, at 12:59 PM, Michael Tharp g...@partiallystapled.com wrote: On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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. ___ 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] REF osc distribution.
Hi Bob; There are many designs I have seen employed at NIST that have low phase noise and low noise floor. But it is often not that easy to build a working prototype that actual achieves those levels of performance. power supply design, parts layout, shielding, and part selection all play a substantial role in achieving that level of performance. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 18:05:41 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi The NIST bipolar designs can indeed do better than a good quality OCXO for short term and close in phase noise. If you have a wide band floor at -185 dbc/Hz on your OCXO they aren't quite up to that level. Bob On Sep 5, 2012, at 5:55 PM, Tom Knox act...@hotmail.com wrote: I have seen that many commercial ref distribution amps are not as good as a quality low phase noise 5 or 10MHz oscillator, considering the time and resources that went into their design I think it would be difficult to design a amp capable of distributing something much cleaner then a LPRO. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 17:37:34 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi You *can* get the job done with a CMOS inverter biased up and filtered. An op amp is likely not as good as the full bipolar approach and may be better / worse than the gate depending on exactly what you are looking at. Bob On Sep 5, 2012, at 12:59 PM, Michael Tharp g...@partiallystapled.com wrote: On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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. ___ 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] REF osc distribution.
A couple links on what Bob is referencing: http://www.ko4bb.com/~bruce/IsolationAmplifiers.html http://www.ke5fx.com/norton.htm On 9/5/2012 9:46 AM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rui Martins Sent: Wednesday, September 05, 2012 10:19 AM To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Bob and Paul, I have at moment 6 equipment's maximum which I want sync with 10MHZ only. The video distribution is an idea but the kit from Ve2zaz have other way but the problem is the isolation. I have 2 independent Nortel GPSTM but I don't need redundancy for the job. G3ruh and ve2zaz Kits and rubidium oscillators only for analyzing the data and compare. I will use one of them with a doubler to get 20MHZ for driving a transceiver (Crazy huh). Any ideas will be considered. Regards CT1EBH Rui Jorge Martins Proudly user of FT-ONE, FT-980, FT736R, FT726R, FT-2000 and FL-7000 73! ___ 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] REF osc distribution.
It is even more difficult when the schematic is wrong like in figure 1 where the emitter and collector of the PNP are reversed. On Wed, 5 Sep 2012 16:26:04 -0600, Tom Knox act...@hotmail.com wrote: Hi Bob; There are many designs I have seen employed at NIST that have low phase noise and low noise floor. But it is often not that easy to build a working prototype that actual achieves those levels of performance. power supply design, parts layout, shielding, and part selection all play a substantial role in achieving that level of performance. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 18:05:41 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi The NIST bipolar designs can indeed do better than a good quality OCXO for short term and close in phase noise. If you have a wide band floor at -185 dbc/Hz on your OCXO they aren't quite up to that level. Bob On Sep 5, 2012, at 5:55 PM, Tom Knox act...@hotmail.com wrote: I have seen that many commercial ref distribution amps are not as good as a quality low phase noise 5 or 10MHz oscillator, considering the time and resources that went into their design I think it would be difficult to design a amp capable of distributing something much cleaner then a LPRO. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 17:37:34 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi You *can* get the job done with a CMOS inverter biased up and filtered. An op amp is likely not as good as the full bipolar approach and may be better / worse than the gate depending on exactly what you are looking at. Bob On Sep 5, 2012, at 12:59 PM, Michael Tharp g...@partiallystapled.com wrote: On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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] REF osc distribution.
Hi There's actually a prior paper on the figure 1 amp. Bob On Sep 5, 2012, at 6:38 PM, David davidwh...@gmail.com wrote: It is even more difficult when the schematic is wrong like in figure 1 where the emitter and collector of the PNP are reversed. On Wed, 5 Sep 2012 16:26:04 -0600, Tom Knox act...@hotmail.com wrote: Hi Bob; There are many designs I have seen employed at NIST that have low phase noise and low noise floor. But it is often not that easy to build a working prototype that actual achieves those levels of performance. power supply design, parts layout, shielding, and part selection all play a substantial role in achieving that level of performance. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 18:05:41 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi The NIST bipolar designs can indeed do better than a good quality OCXO for short term and close in phase noise. If you have a wide band floor at -185 dbc/Hz on your OCXO they aren't quite up to that level. Bob On Sep 5, 2012, at 5:55 PM, Tom Knox act...@hotmail.com wrote: I have seen that many commercial ref distribution amps are not as good as a quality low phase noise 5 or 10MHz oscillator, considering the time and resources that went into their design I think it would be difficult to design a amp capable of distributing something much cleaner then a LPRO. Thomas Knox From: li...@rtty.us Date: Wed, 5 Sep 2012 17:37:34 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] REF osc distribution. Hi You *can* get the job done with a CMOS inverter biased up and filtered. An op amp is likely not as good as the full bipolar approach and may be better / worse than the gate depending on exactly what you are looking at. Bob On Sep 5, 2012, at 12:59 PM, Michael Tharp g...@partiallystapled.com wrote: On 09/05/2012 12:46 PM, Bob Camp wrote: Hi There are a number of discrete transistor buffers that have very good isolation and short term stability / phase noise performance. I'd take a look at the one from the NIST papers and Bruce's more modern re-design. All are in the archives. http://tf.boulder.nist.gov/general/pdf/498.pdf is a pretty good place to start. Mostly what they do is to run a common emitter amplifier followed by several common base amplifiers. They may or may not follow that with a buffer. Each channel gets a separate string of amplifiers. All the common emitter amps are driven in parallel by the reference source. The transistors used are normally cheap stuff like the 2N3904. Except for the power supply nothing in the circuit costs much. None of it is hard to find. For an integrated (op-amp) solution, how does OPA830 stack up? I'm trying one out for a GPSDO design to buffer the signal from the OCXO for 50 ohm output, but I may also build a distribution amplifier at some point. At $1.91 for single pieces on Digi-Key it's not terribly expensive, but something cheaper could probably get the job done. There are also dual and quad versions (OPA2830 and OPA4830). -- m. tharp ___ 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] REF osc distribution.
Hi Lots of choices: 1)do you need 1 pps distributed? 2)do you need 100 KHz, 1MHz, 5MHz (or really odd frequencies) for anything? 3)how many 10 MHz gizmos do you have? 4)Do you need / want to receive 10 MHz radio signals while distributing 10 MHz? (same question for other frequencies if you use therm). 5)What are you running the signals to? / how clean does the phase noise need to be? 6)What are you running the signals to? / how good does the short term stability need to be? 7)(same)/ how good does the isolation need to be? 8)(same)/ do you need redundancy or anything else unusual? For simple need to run a frequency counter needs, video amps are often the easy choice. For more demanding gear, you can have very complex distribution systems. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rui Martins Sent: Tuesday, September 04, 2012 9:23 AM To: time-nuts@febo.com Subject: [time-nuts] REF osc distribution. Hi, At the moment my GPSTM have 1.3e-012 in alan deviation and it's time to connect to the equipements. Which is the best way to do it? CT1EBHT Rui Jorge Martins 73! ___ 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.
