Re: [time-nuts] Phase Detectors/Mixers for DMTD and PN measurements
Cross Correlation methods are commonly used with analog mixers. Most of the high end commercial offerings use it (Holzworth, Anapico, Rhohde & Schwarz, etc.) Bruce > On 12 December 2019 at 18:53 Gerhard Hoffmann > wrote: > > > It seems the mixer noise cannot be ignored. > > > I wonder then why nobody takes the mixer to cross correlation land, > and maybe even the driver amplifier. > > The FFT analyzer can do it anyway, a second AF pre amp costs nothing, > and other than that > > there are only another mixer and 2 power dividers on the BOM. > > In addition, each mixer gets 3 dB less power which helps the survival rate. > > One can always crank it up for bragging rights. > > > Also, high level mixers (type 2 and 3 in [1] ) have resistors in series > to each diode for biasing > > so their lower efficiency should not come as a surprise. And, the > resistors in the ring generate > > AF noise. With DC across them also 1/f, esp. for thick film. > > The usual 1nV/rt Hz op amps (LT1028, AD797, ADA4898) have the voltage > noise of a 60 Ohm resistor. > > That probably brings them to the point of diminishing return. > > The diodes in the ring themselves create only half-thermal noise. > > > Methinks one would be better off with many low level mixers and power > dividers, > > adding up the demodulated AF voltages. There is no point in power > matching the AF side. > > Maybe for RF with a RC high pass. > > SMD Wilkinson dividers are $2.50 or so now from Macom, MCL or Pulse and > > low level mixers are also cheap, or even 2 1:4 SMD transformers + diode > ring. > > Easily done when one does not have to wind the coils. > > > When verifying my links below, I stumbled across M9H for $333. > > The price for two of them is the number of the beast. =8-) ) > > > [1] > > < > https://www.jlab.org/uspas11/Reading/RF/Mixers%20-%20phase%20detectors.pdf > > > > < > https://www.google.de/url?sa=t=j==s=web=1=2ahUKEwiu8Zi7pa_mAhUKQUEAHb1pAyAQFjAAegQIAxAJ=http%3A%2F%2Fwww.rfcafe.com%2Freferences%2Farticles%2Fwj-tech-notes%2Fmixers-theory-technology-p2-v8-3.pdf=AOvVaw3fc3OZgN2H5jzPx6jXDBh9 > > > > > > Also interesting: > > < > https://www.google.de/url?sa=t=j==s=web=1=rja=8=2ahUKEwiFuqCvpq_mAhVTh1wKHcc2ALQQFjAAegQIAxAJ=http%3A%2F%2Fliterature.cdn.keysight.com%2Flitweb%2Fpdf%2F5989-8999EN.pdf=AOvVaw3RFawCNg543QEv1hUsscbY > > > > > > regards, > > Gerhard, DK4XP > > > > > Am 11.12.19 um 20:29 schrieb Bob kb8tq: > > Hi > > > > There are some famous name papers showing data taken on the 3048. When > > asked about the levels involved, the next question inevitably was - “How > > many > > mixers did you fry running the test?”. > > > > Bob > > > >> On Dec 11, 2019, at 10:54 AM, Richard (Rick) Karlquist > >> wrote: > >> > >> > >> The HP 3048A phase noise system has a phase > >> detector in the HP 11848A chassis that was > >> originally a Watkins-Johnson (the original > >> company) M9H. The M9H lives on now sold by > >> MaCom Technology Solutions. "Someone" (unknown) > >> established that the Mini-Circuits JMS-5H > >> is an acceptable substitute, although not > >> an exact replacement. > >> > >> The tradeoff in picking a mixer is the LO > >> level. A high LO drive level such as the above > >> mixer have, gives higher performance, provided > >> you have a driving amplifier that has both the > >> necessary output power is itself low phase noise. > >> Depending on the test set up, some of the driver > >> amplifier phase noise will common mode out. > >> > >> Also, high drive level mixers have a narrow window > >> between high enough drive to operate vs the damage > >> level. So a third requirement on the driver > >> amplifier is that it's maximum output level is > >> less than the damage level. (Don't ask how I > >> know this :-). You can always put a pad between the > >> drive amplifier and the LO input of the mixer used > >> as phase detector to adjust the maximum possible > >> drive. > >> > >> Rick N6RK > >> > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Phase Detectors/Mixers for DMTD and PN measurements
It seems the mixer noise cannot be ignored. I wonder then why nobody takes the mixer to cross correlation land, and maybe even the driver amplifier. The FFT analyzer can do it anyway, a second AF pre amp costs nothing, and other than that there are only another mixer and 2 power dividers on the BOM. In addition, each mixer gets 3 dB less power which helps the survival rate. One can always crank it up for bragging rights. Also, high level mixers (type 2 and 3 in [1] ) have resistors in series to each diode for biasing so their lower efficiency should not come as a surprise. And, the resistors in the ring generate AF noise. With DC across them also 1/f, esp. for thick film. The usual 1nV/rt Hz op amps (LT1028, AD797, ADA4898) have the voltage noise of a 60 Ohm resistor. That probably brings them to the point of diminishing return. The diodes in the ring themselves create only half-thermal noise. Methinks one would be better off with many low level mixers and power dividers, adding up the demodulated AF voltages. There is no point in power matching the AF side. Maybe for RF with a RC high pass. SMD Wilkinson dividers are $2.50 or so now from Macom, MCL or Pulse and low level mixers are also cheap, or even 2 1:4 SMD transformers + diode ring. Easily done when one does not have to wind the coils. When verifying my links below, I stumbled across M9H for $333. The price for two of them is the number of the beast. =8-) ) [1] < https://www.jlab.org/uspas11/Reading/RF/Mixers%20-%20phase%20detectors.pdf > < https://www.google.de/url?sa=t=j==s=web=1=2ahUKEwiu8Zi7pa_mAhUKQUEAHb1pAyAQFjAAegQIAxAJ=http%3A%2F%2Fwww.rfcafe.com%2Freferences%2Farticles%2Fwj-tech-notes%2Fmixers-theory-technology-p2-v8-3.pdf=AOvVaw3fc3OZgN2H5jzPx6jXDBh9 > Also interesting: < https://www.google.de/url?sa=t=j==s=web=1=rja=8=2ahUKEwiFuqCvpq_mAhVTh1wKHcc2ALQQFjAAegQIAxAJ=http%3A%2F%2Fliterature.cdn.keysight.com%2Flitweb%2Fpdf%2F5989-8999EN.pdf=AOvVaw3RFawCNg543QEv1hUsscbY > regards, Gerhard, DK4XP Am 11.12.19 um 20:29 schrieb Bob kb8tq: Hi There are some famous name papers showing data taken on the 3048. When asked about the levels involved, the next question inevitably was - “How many mixers did you fry running the test?”. Bob On Dec 11, 2019, at 10:54 AM, Richard (Rick) Karlquist wrote: The HP 3048A phase noise system has a phase detector in the HP 11848A chassis that was originally a Watkins-Johnson (the original company) M9H. The M9H lives on now sold by MaCom Technology Solutions. "Someone" (unknown) established that the Mini-Circuits JMS-5H is an acceptable substitute, although not an exact replacement. The tradeoff in picking a mixer is the LO level. A high LO drive level such as the above mixer have, gives higher performance, provided you have a driving amplifier that has both the necessary output power is itself low phase noise. Depending on the test set up, some of the driver amplifier phase noise will common mode out. Also, high drive level mixers have a narrow window between high enough drive to operate vs the damage level. So a third requirement on the driver amplifier is that it's maximum output level is less than the damage level. (Don't ask how I know this :-). You can always put a pad between the drive amplifier and the LO input of the mixer used as phase detector to adjust the maximum possible drive. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Phase Detectors/Mixers for DMTD and PN measurements
HI For quite a while, the “quick and easy” way to do it has been to run one of the Mini Circuits RPD parts into a > 5K load at audio. You get a nice big output voltage without a lot of crazy effort. Follow it with the highest voltage / lowest noise op amp you can find …. Bob > On Dec 11, 2019, at 5:36 AM, Bruce Griffiths > wrote: > > There are a number of NIST papers on this: > https://tf.nist.gov/general/publications.htm > > You can also simulate the effect of a capacitive IF port load. > However a capacitive load can also degrade the isolation and RF and LO port > mismatch. > > One can also use diode connected BJTs instead if lower close in PN is desired > at least for frequencies up to 10MHz or so. > There is a NIST paper on this as well: > https://tf.nist.gov/general/pdf/2556.pdf > > Bruce > >> On 11 December 2019 at 22:55 Tobias Pluess wrote: >> >> >> Hi colleagues >> >> In parallel to my GPSDO project I am also thinking about a DMTD measurement >> system which should also be capable of doing phase noise measurements. This >> will be necessary to measure the stability and phase noise of my own GPSDO. >> >> There is the paper from W. J. Riley, "A small DMTD system". He uses >> TUF-R3SM+ mixers. The HP 11729C carrier noise test set uses a custom HP part >> as phase detector, and a lot of other publications I found use the HP >> 10514A, either as mixer or as phase detector. >> I wonder, which criteria are relevant to select a mixer for this application >> (besides the frequency range). Are there devices which are better when used >> as mixers, or phase detectors, or are there even devices which are good for >> both purposes? Of course, we want low noise, but for most if not all >> commercial mixers, only the isolation and conversion loss is specified, but >> I never saw a mixer datasheet having information about the mixer's noise >> contribution. So there must be other criteria people use when selecting a >> mixer for a DMTD or phase noise measurement system. >> >> Further. in this paper "OPTIMIZATION OF DUAL-MIXER TIME-DIFFERENCE >> MULTIPLIER" from Sojdr I even found a reference "The mixer output has a >> capacitive loading (22 nF) that increases the zero-crossing slope". The >> "Small DMTD system" from Riley also does have this capacitive loading. Can >> somebody explain why this does help to improve the zero crossing slope? >> >> >> Tobias >> HB9FSX >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Trimble 57963
Hi 5V and even 3.3V OCXO’s are fairly common these days. They show up in the catalog pages of a number of outfits and have for a decade or two. Trimble buys OCXO’s on the open market. They have used several suppliers over the years. The spec’s are indeed unique to Trimble, but by no means exotic. On > 90% of all OCXO’s made, having a spec / part number that is unique to an application makes the procurement process easier (on both ends). Bob > On Dec 10, 2019, at 7:38 PM, Roger Tilsley wrote: > > Greetings Robert, > > I have one of these and it works very well running on 6 V. I have been > warned off low operating voltage OCXOs by an OCXO manufacturer. This > manufacturer would not countenance manufacturing OCXOs operating on 5 V. > There is little technical information available, I tried Trimble for info > and was told that it was designed for a specific customer and that all the > information was customer confidential - if I had paid a contractor a > substantial sum to produce a specific design for me, I would not be happy if > the manufacturer sent technical details to anyone who enquired! I can > therefore understand the policy and it does explain the shortage of technical > information. > > Regards, > Roger T. > > On Tue, 10 Dec 2019 09:43:23 -0500, Robert DiRosario > wrote: > >> I just received an Trimble 57963-D GPSDO with a Trimble 73090 OCXO. >> >> There is very little information about this on the web. What voltage >> does this run on? >> >> Some information I found online says 6 volts. The seller says 5.5V. I >> got it from ebay / China. >> >> I did get a breakout board and the 50 pin cable. \ >> >> Thanks >> Robert >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Phase Detectors/Mixers for DMTD and PN measurements
There are a number of NIST papers on this: https://tf.nist.gov/general/publications.htm You can also simulate the effect of a capacitive IF port load. However a capacitive load can also degrade the isolation and RF and LO port mismatch. One can also use diode connected BJTs instead if lower close in PN is desired at least for frequencies up to 10MHz or so. There is a NIST paper on this as well: https://tf.nist.gov/general/pdf/2556.pdf Bruce > On 11 December 2019 at 22:55 Tobias Pluess wrote: > > > Hi colleagues > > In parallel to my GPSDO project I am also thinking about a DMTD measurement > system which should also be capable of doing phase noise measurements. This > will be necessary to measure the stability and phase noise of my own GPSDO. > > There is the paper from W. J. Riley, "A small DMTD system". He uses TUF-R3SM+ > mixers. The HP 11729C carrier noise test set uses a custom HP part as phase > detector, and a lot of other publications I found use the HP 10514A, either > as mixer or as phase detector. > I wonder, which criteria are relevant to select a mixer for this application > (besides the frequency range). Are there devices which are better when used > as mixers, or phase detectors, or are there even devices which are good for > both purposes? Of course, we want low noise, but for most if not all > commercial mixers, only the isolation and conversion loss is specified, but I > never saw a mixer datasheet having information about the mixer's noise > contribution. So there must be other criteria people use when selecting a > mixer for a DMTD or phase noise measurement system. > > Further. in this paper "OPTIMIZATION OF DUAL-MIXER TIME-DIFFERENCE > MULTIPLIER" from Sojdr I even found a reference "The mixer output has a > capacitive loading (22 nF) that increases the zero-crossing slope". The > "Small DMTD system" from Riley also does have this capacitive loading. Can > somebody explain why this does help to improve the zero crossing slope? > > > Tobias > HB9FSX > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Phase Detectors/Mixers for DMTD and PN measurements
Hi colleagues In parallel to my GPSDO project I am also thinking about a DMTD measurement system which should also be capable of doing phase noise measurements. This will be necessary to measure the stability and phase noise of my own GPSDO. There is the paper from W. J. Riley, "A small DMTD system". He uses TUF-R3SM+ mixers. The HP 11729C carrier noise test set uses a custom HP part as phase detector, and a lot of other publications I found use the HP 10514A, either as mixer or as phase detector. I wonder, which criteria are relevant to select a mixer for this application (besides the frequency range). Are there devices which are better when used as mixers, or phase detectors, or are there even devices which are good for both purposes? Of course, we want low noise, but for most if not all commercial mixers, only the isolation and conversion loss is specified, but I never saw a mixer datasheet having information about the mixer's noise contribution. So there must be other criteria people use when selecting a mixer for a DMTD or phase noise measurement system. Further. in this paper "OPTIMIZATION OF DUAL-MIXER TIME-DIFFERENCE MULTIPLIER" from Sojdr I even found a reference "The mixer output has a capacitive loading (22 nF) that increases the zero-crossing slope". The "Small DMTD system" from Riley also does have this capacitive loading. Can somebody explain why this does help to improve the zero crossing slope? Tobias HB9FSX ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
