Geller 10 volt ref. Hello WarrenS, Is it possible to have some details of your 1 transistor 1st order temperature modification, on the Geller 10 volt ref. ?
Helge 2008/11/29 <[EMAIL PROTECTED]> > Send time-nuts mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > [EMAIL PROTECTED] > > You can reach the person managing the list at > [EMAIL PROTECTED] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. Re: Calibration and temperature (Lux, James P) > 2. Re: Voltage standards (Bruce Griffiths) > 3. Re: Voltage standards (WarrenS) > 4. Re: any way to bootstrap a frequency standard, into a, > voltage or resistance standard? (Ed Palmer) > 5. Re: Cesium vs H Maser clocks (Tom Van Baak) > 6. Re: Cesium vs H Maser clocks (Brian Kirby) > 7. TBolt TC recs wanted (Richard Moore) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 28 Nov 2008 19:52:35 -0800 > From: "Lux, James P" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Calibration and temperature > To: Discussion of precise time and frequency measurement > <[email protected]> > Message-ID: <[EMAIL PROTECTED]<[EMAIL PROTECTED]> > > > Content-Type: text/plain; charset="iso-8859-1" > > > > > On 11/28/08 11:27 AM, "Bill Hawkins" <[EMAIL PROTECTED]> wrote: > > > > Has any work been done on temperature compensation of quartz or other > > oscillators to avoid the expense, space, and power of ovens? The > > oscillating material must have a repeatable temperature curve, of > > course. > Look at MCXOs, a very clever technique using the different between third > overtone and fundamental to measure the temperature of the rock. > > > Jim Lux > > > > > ------------------------------ > > Message: 2 > Date: Sat, 29 Nov 2008 17:12:40 +1300 > From: Bruce Griffiths <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Voltage standards > To: Discussion of precise time and frequency measurement > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=ISO-8859-1 > > Richard Moore wrote: > > What to do? Seems like a possible stable, yet low-cost source would > > be to buy 10 or so LM399s and hook them up to a power supply to age > > for 6 to 12 months, then use two or four in parallel (with suitable > > resistor buffering) driving a chopper amp like the LT1050 to give > > gain. Powered by a good, stiff regulated supply, and kept away from > > stray air currents, this arrangement wouldn't cost as much as a > > single LTZ1000A (which in singles is over $100 USD) > LTZ1000A list price is about $54 (excluding freight and taxes) when > ordering from Linear Technology. > The LTC1050 is a bit marginal unless you bootstrap its power supply the > LTC1151 is a better fit. > > and -- dang it, > > there's always a catch -- after lab calibration, could be a source > > that might need adjustment only once every few years to stay within 5 > > or 10ppm or so. Paralleling more LM399s would be better, and with an > > initial purchase of 10, you could throw away the stinkers and > > parallel all the rest. So, short of having a Fluke 732A or those > > 8-1/2 digit meters, that's my recommendation for a low-cost V > > standard. Unless you know someone, it'll cost less to build than to > > calibrate... > > > > Dick Moore > > > > > > > Bruce > > > > > ------------------------------ > > Message: 3 > Date: Fri, 28 Nov 2008 20:51:12 -0800 > From: "WarrenS" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Voltage standards > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="iso-8859-1" > > > Just to add my experiences and throw in another two cents worth. > I live in California, and a few years back I did some experiments > with Geller on the East coast shipping back and forth some of his 10V > References in the regular mail that I had added a simple 1 transistor > 1st order Temperature compensation circuit to some of his selected aged > units and proved to my satisfaction that better than 2PPM transfer > accuracy was obtained across the country. In house I can consistently > get better than 1 PPM transfer with the same units. Of course there > are more accurate ways, but for us cheap guys It sure beats the $500 > I heard Fluke charges to do their underlying Fluke 732B calibration. > > WarrenS > ********************* > > RE Message 8 and a couple of earlier posts on standards > > > Date: Sat, 29 Nov 2008 10:38:53 +1300 > > From: Bruce Griffiths <bruce.griffiths at xtra.co.nz> > > Subject: Re: [time-nuts] any way to bootstrap a frequency standard > > into a, voltage or resistance standard? > > To: Discussion of precise time and frequency measurement > > <time-nuts at febo.com> > > Message-ID: <493064ED.1030501 at xtra.co.nz> > > Content-Type: text/plain; charset=ISO-8859-1 > > > > WB6BNQ wrote: > >> Ed, > >> > >> No way in hell does that thing qualify as a voltage standard. It > >> barely qualifies as a VERY short term transfer device assuming the > >> temperature does not change. > >> > >> If you want a real voltage reference then buy, from eBay, a Fluke > >> 731B voltage standard. You will still need to get it calibrated, > >> but then it will hold under 10ppm for well over a year or > >> more. Actually, if they are adjusted correctly, you can get less > >> than 5ppm and it will hold it at a given temperature. These items > >> are serious devices and their latest versions (very expensive) > >> are better than a properly maintained and operated group of > >> standard cells. > >> > > The latest Fluke voltage standards use a selected LTZ1000 plus a > > precision resistor array. > > The earlier versions used selected Motorola zener diode references. > > The latest versions allow the LTZ1000 chip temperature to be cycled to > > largely eliminate hysteresis which may occur when they lose power > > during > > shipment. > >> Bill....WB6BNQ > > > > Bruce > > Since we've kinda strayed from the original topic, I'll throw in a > couple of cents. The V references in these 6-1/2 and 7-1/2 digit DMMs > (that I currently own at least one each of): Keithley 196, HP 3456, > 3457, and 34401, use selected -- some more than others -- National > LM199/299/399 series references, which have their own heaters. The > Datron 1080 series (that I own two of), as well as the 1070 series > and 1060 series, use selected pairs of zeners connected in parallel, > but not housed in ovens. The Fluke 8502/05/06 (and my Fluke 510A ACV > std) use the aforementioned Motorola transistor+buried zener > reference, also not in ovens. > > The HP 3458, as mentioned before, uses the Linear LTZ1000/1000A, > which has its own heater. As to others, the old Fluke 895A, 887A, and > 885A 6-digit analog Differential Meters (with K-V bridges for > comparing the reference to the unknown in various ways), all use a > pair of zeners in series, in an oven. A Fluke engineer told me years > ago that those zeners were selected to have slightly different TC > peaks so when one was falling in V the other was rising, so that they > would spread the peak over a larger temperature range. They had a > very elaborate automated system for testing the temp, voltage, and > current values to do the pairing. > > My Fluke 732A DC reference standard, which uses the Motorola > transistor+buried zener reference, housed in an oven together with > all of the various fixed and variable resistors and the other active > devices, has an extremely low drift rate -- unmeasurable over a month > in any definitive way -- as measured with a rented HP 3458A. I have > disabled the batteries because I discovered, thanks to the 3458A, > that when turned off, cooled off, and turned back on, within a day, > the output returned within 0.05ppm to it's cal'd value -- I know > there can be hysteresis, I just couldn't see it. > > I have one of the little Geller 10V refs built around the AD587 > reference chips, and if you keep it enclosed and away from air > currents, it's pretty stable, but would need to be in an oven to > approach the performance of the LM199 series. > > All this is to say that if you can get a working HP 3458A or a Datron > 1280 series (which is also the Fluke 8805), or a Datron 1270 series > meter, all of which are self-calibrating in various ingenious ways, > it will serve you well as a secondary standard for measurement on > everything that it can measure. I can't, or more properly, won't at > the moment, spend the current freight of around $4,000 USD for a > known good working 3458 or 1281. > > What to do? Seems like a possible stable, yet low-cost source would > be to buy 10 or so LM399s and hook them up to a power supply to age > for 6 to 12 months, then use two or four in parallel (with suitable > resistor buffering) driving a chopper amp like the LT1050 to give > gain. Powered by a good, stiff regulated supply, and kept away from > stray air currents, this arrangement wouldn't cost as much as a > single LTZ1000A (which in singles is over $100 USD) and -- dang it, > there's always a catch -- after lab calibration, could be a source > that might need adjustment only once every few years to stay within 5 > or 10ppm or so. Paralleling more LM399s would be better, and with an > initial purchase of 10, you could throw away the stinkers and > parallel all the rest. So, short of having a Fluke 732A or those > 8-1/2 digit meters, that's my recommendation for a low-cost V > standard. Unless you know someone, it'll cost less to build than to > calibrate... > > Dick Moore > > > > ------------------------------ > > Message: 4 > Date: Fri, 28 Nov 2008 23:18:39 -0600 > From: Ed Palmer <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] any way to bootstrap a frequency standard, > into a, voltage or resistance standard? > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Bill, > > I agree with the comments made by you and everyone else. That's why I said > "..if it's good enough..". But there's one thing that kind of slid by > everyone. All the other suggestions conclude with some variation of > "..needs to be calibrated..". Is there any other way to get a > NIST-traceable voltage into your shop for $35? (I'm not challenging you, > I'd really like to know if there is another alternative) Granted, it's only > at the 10 uv level, but for many applications that *is* good enough. > > Let's be honest, as time-nuts we're spoiled rotten. Almost all of us have > got rubidium standards at 10E-11 per day or better and at a ridiculously low > price. Many have got cesium standards and a few have got hydrogen masers. > We can calibrate them against GPS or Loran-C to obsessive-compulsive > levels. So far, none of the other physical standards allow that level of > independence for hobbyists. So when dealing with other measurement units > (e.g. volts, ohms, etc) we either have to ease the requirements by orders of > magnitude or increase the budget by orders of magnitude! > > If you're doing this as part of your job and can justify the need and the > expense - great! I'm a hobbyist and I won't be spending $1843 any time soon > to have NIST calibrate a DC solid-state voltage reference. For my needs > Geller Labs provides good value for the very nominal cost. > > And just to be clear, I have no relationship with Geller Labs. > > Ed > > WB6BNQ wrote: > > > No way in hell does that thing qualify as a voltage standard. It barely > qualifies as a VERY short term transfer device assuming the temperature does > not change. > > > > If you want a real voltage reference then buy, from eBay, a Fluke 731B > voltage standard. You will still need to get it calibrated, but then it > will hold under 10ppm for well over a year or > > more. Actually, if they are adjusted correctly, you can get less than > 5ppm and it will hold it at a given temperature. These items are serious > devices and their latest versions (very expensive) > > are better than a properly maintained and operated group of standard > cells. > > > > I completely disagree with Brian about buying any standard cells. > Whatever voltage value they had is lost upon shipment. Shaking the cells > changes the value and it will not return to the > > original value. If you did have a set of cells, you would want at least > 4 of them. Then study statistical math all over again because you will need > it to use the cells. > > > > As Brian does suggest, you would be much better off picking up a hp3456A, > 3457A, 3458A or getting one of Fluke 8500 series if it has the Ohms and AC > options included. The basic Fluke 8500 series > > is DC only mainframe. > > > > Measuring your resistors, using one of the above DVMs, in the 4-wire mode > is about the best you could possibly do. To do any better would require > some very serious effort. > > > > By the way you could buy several of the latest and greatest Fluke super > DVMs for the cost of what it would take to do a Josephson array and still > have money left over to fund that divorce. > > > > Bill....WB6BNQ > > > > > > Ed Palmer wrote: > > > > > >> It's nowhere near the idea of a Josephson array, but if a NIST-traceable > 10V +-10uV reference is good enough to satisfy your voltage-nut urges, you > can buy it from www.gellerlabs.com for $35. > >> > >> I also have a few standard resistors (e.g. 1.000002 ohms) that I'd be > interested in calibrating, but I can't seem to come up with a practical way > of doing it. > >> > >> Frustrating, isn't it? :-) > >> > >> Ed > >> > > > ------------------------------ > > Message: 5 > Date: Fri, 28 Nov 2008 22:30:33 -0800 > From: "Tom Van Baak" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Cesium vs H Maser clocks > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; format=flowed; charset="Windows-1252"; > reply-type=original > > > Isn't the temperature the _only_ thing to correct for? > > No, not at all. Read the links that I provided to see that a real > cesium standard is not quite so simple, at least when you get > down to the ten to the -13, -14, -15 levels. At that level there > are all sorts of cool things that push or pull the frequency and > need to be corrected for. > > > The definition of the second is "...the duration of 9 192 631 770 > > periods of the radiation corresponding to the transition between the > > two hyperfine levels of the ground state of the cesium 133 atom." (and > > affirmed by the CIPM in 1997 that this definition refers to a cesium > > atom in its ground state at a temperature of 0 K) > > Right. But realize that most of the cesium standards that we use > are not running at 0 Kelvin. So there is a correction for that. > > In order for cesium beam standards to even work, one must apply > a slight magnetic field, the so-called C-field, which rather strongly > distorts the shape of the resonance peak. The definition assumes > zero magnetic field, so this too must be modeled and corrected for. > That's why, for example, the hp 5062c runs at 9,192,631,774.3133 Hz, > not the textbook 9,192,631,770 Hz. An internal synthesizer takes > care of this correction. > > The NIST papers list a dozen or so of these corrections, each of > which is a nice lesson in atomic physics by itself. > > Note also that clocks at NIST run about 1.8e-13 fast due to the high > elevation of Boulder, CO (general relativity), which is yet another > factor that has to be corrected for compared to the official sea-level > definition of the second. > > > That other factors can change the relative frequency of different Cs > > clocks is a problem with the definition, not an indication that any > > particular one is better than another. If a magnetic field changes the > > relative frequency, but that isn't reflected in the definition, is it > > not the definition which is faulty, and not the timepiece? The second > > is imprecise in this regard. > > The definition is fine -- it applies to the ideal conditions. But if you > decide to build an apparatus to implement the definition, and if for > whatever reason the ideal conditions can't be met in your apparatus, > then is it up to you, the clock builder, to anticipate this and make > corrections for it so that your clock still counts SI seconds at the > output BNC connector. > > The other thing to note is that most cesium standards come with a > specification, based on design. I don't have the exact numbers but > a 5061A might be accurate out-of-the-box to 1e-11 while a 5071A > might be accurate to 1e-13. This reflects the difference in design, > manufacturing tolerances, and the number of internal frequency > offsets that are controlled or compensated for in hardware or in > firmware. So the definition of the SI second is fine; it's just that > some clocks can get closer to realizing the definition than others. > > /tvb > > > > > ------------------------------ > > Message: 6 > Date: Sat, 29 Nov 2008 01:25:39 -0600 > From: Brian Kirby <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Cesium vs H Maser clocks > To: Tom Van Baak <[EMAIL PROTECTED]>, Discussion of precise time and > frequency measurement <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > The clocks (rubidium and cesium) in the GPS satellites are also run at a > different frequency because of their altitudes.... > > Also magnetic field are different on the earth and they sometimes adjust > the "C" fields to correct for these differences. > > >> Isn't the temperature the _only_ thing to correct for? > > > > No, not at all. Read the links that I provided to see that a real > > cesium standard is not quite so simple, at least when you get > > down to the ten to the -13, -14, -15 levels. At that level there > > are all sorts of cool things that push or pull the frequency and > > need to be corrected for. > > > >> The definition of the second is "...the duration of 9 192 631 770 > >> periods of the radiation corresponding to the transition between the > >> two hyperfine levels of the ground state of the cesium 133 atom." (and > >> affirmed by the CIPM in 1997 that this definition refers to a cesium > >> atom in its ground state at a temperature of 0 K) > > > > ------------------------------ > > Message: 7 > Date: Sat, 29 Nov 2008 00:14:04 -0800 > From: Richard Moore <[EMAIL PROTECTED]> > Subject: [time-nuts] TBolt TC recs wanted > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > Dear nuts -- What TBolt time constant setting have you found to work > best for best frequency accuracy and-or stability? > > Dick Moore > > > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 52, Issue 85 > ***************************************** > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
