Re: [time-nuts] xtal oscillator phase noise
Grant Hodgson wrote: > Henk > > Two things will dominate if you want such a low phase noise spec.:- the > loaded Q of the oscillator circuit, and the flicker corner frequency > of the sustaining amplifier transistor. To get a high loaded Q you need > a crystal with a high unloaded Q - maybe 100 000 or more - this isn't > difficult to achieve from a good crystal manufacturer, but you can't > expect any old crystal to work. And the rest of the oscillator circuit > should not load the crystal too much, otherwise the loaded Q, and thus > phase noise, will suffer. Good crystal manufacturers will provide the > necessary measurements of series resistance, motional inductance (or > capacitance, or unloaded Q - doesn't matter which) and static > capacitance. Lesser crystal manufacturers - don't. > > A Q of 100,000 at 10MHz produces a Leeson effect phase noise corner of 100Hz (below which the phase noise slope is 20dB/decade). This makes it much harder to achieve the desired phase noise at 10Hz than a crystal with a Q of 1,000,000. > Also the flicker corner frequency of the transistor needs to be as low > as possible. Generally speaking, at offsets below the flicker corner > frequency you will get 30dB/decade, above the flicker corner frequency > you should get 20dB/decade, or flat, depending on the level of the phase > noise floor. If you can find a transistor with a lower corner > frequency, the flicker noise will be reduced. In fact, this is one of > the dominant parameters when choosing a transistor as an oscillator - > any old transistor can be made to oscillate, but to do so with a low > flicker corner frequency is not so easy, and the corner frequency is > usually a function of bias current. > > Its not quite that simple, the flicker phase modulation depends on the voltage and/or current dependence of the various transistor capacitances etc and the consequent phase modulation produced by low frequency noise currents flowing through the transistor or low frequency noise voltages developed across such capacitances. Simply choosing a low flicker noise transistor without taking its collector base capacitance, emitter base capacitance, etc into account is unlikely to reduce the flicker phase noise. Reducing the dc gain from the base to the collector and ensuring that the emitter current low frequency noise is low is likely to be more effective. Increasing the collector base voltage will reduce the collector base capacitance and its voltage dependence. The oscillator power supply noise can also modulate the transistor collector current and thus increase the phase noise. > At 11MHz, most crystal oscillators use parallel resonant crystals, > although some are series resonant, such as the excellent Driscoll > oscillator which is capable of the performance you desire with a > suitable crystal. > > Then you have the added problem of the FSUP. It's a superb instrument, > but it has it's limitations. The FSUP data sheet states a phase noise > spec. of -130dBc at 10Hz offset for a 10MHz signal, which gives a > resulting sensitivity of -127dBc - 3dB worse than what you are trying to > achieve. You would need option B60 (cross correlation) to significantly > reduce the effect of the internal source by (say) 15db or so. > > regards > > Grant > > The measured oscillator phase noise floor seems a little high for a modern low phase noise design. If the oscillator uses varicap diodes to adjust the oscillation frequency, these can contribute significantly to the phase noise especially if their tuning range is large. Testing the oscillator without varicaps (if possible) and with lower noise supplies may also be useful. Failing removal of such varicaps reconfiguring the EFC so that the varicap has a much smaller tuning range (supplemented by a manual trimmer) may be useful in reducing the phase noise contribution of the EFC circuit. Use a capacitive attenuator to reduce the EFC range, not a resistive attenuator on the EFC control voltage. Bruce ___ 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] RCC 8000
Hi Nigel, Thanks for the offer, well I am not in a hurry, just take your time.I have many other project to go on. About 10-15years ago I tried to copy MFS but due to the close proximity of DCF I was unable to copy maybe I did not pay attention to the selective active antenna and so on. do you think that I will be able? to receive MFS in Frankfurt? Cheers, Ernie. -Original Message- From: [EMAIL PROTECTED] To: time-nuts@febo.com Sent: Sun, 30 Dec 2007 7:04 pm Subject: Re: [time-nuts] RCC 8000 In a message dated 30/12/2007 17:45:51 GMT Standard Time, [EMAIL PROTECTED] writes: Yes , I tried RadioClocks UK but no helping hand...they offered if I ship the unit back to the factory, ??? they give a price for the conversion./ assume to expensive /... ??? I am living about 25km from DCF77 in Germany, so believe the receiver part is not a big deal, ??? but the "code " is different then MSF60 - Hi Ernie I have some paperwork on the RCC8000, part, if not all, of some sort of manual and perhaps some schematics too. If that sounds vague it's because it was sent to me a few years ago and soon ended up in storage. I didn't reply earlier as I couldn't find it at home, which means it's probably still buried in storage and I have no idea when I'm likely to find it. If nobody else has a copy, and you don't mind waiting, I'm happy to share what I've got. It might be soon, but it could be quite a wait. I have a couple of RCC8000s, also buried somewhere so it's a while since I've seen them too, but I suspect any difference, aside from a fairly minor retune of the receiver, is going to be in the firmware. Both mine are for MSF and I have no idea whether or not there will be any firmware information in the documentation I have. I know it'll be a pain if you're so close to DCF77, but I don't think it should be very difficult to knock up a reasonable antenna for MSF, which might make life a lot easier. 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. More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.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] accurate portable time source
Hi Ronald: Not yet. Right now I'm having fun with old DC motors and Flashlights. http://www.prc68.com/I/EM_ToyEngine.shtml http://www.prc68.com/I/Gilbert-Motor.shtml http://www.prc68.com/I/Weeden-El-Motor.shtml http://www.prc68.com/I/FlashlightPat.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam Ronald Held wrote: > Brooke: > Have you tried out your last idea at least in a test configuration? >Ronald > > > > > Message: 1 > Date: Fri, 28 Dec 2007 15:19:49 -0800 > From: Brooke Clarke <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] accurate portable time source > To: Discussion of precise time and frequency measurement > <> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=us-ascii; format=flowed > > Hi Ronald: > > Here are a some of ideas for the heart beat for a LCD based clock like the > ones > I've been developing. > > Best) A Vectron EX-380 series Vacuum OCXO only draws 0.35 Watts and if the 5 > volt version that's only 70 ma. So a single AA would have enough energy, > three > AAA Ni-MH would be great. That was the good news. The bad news is that they > are made of unobtanium (i.e. very expensive or need to be bought in large > lots). > > Good) An alternative is the DS3231. This is an advanced version of the > DS32khz > TCXO and is adjustable to 0.1 ppm using the digital serial interface. > Provision for a coin cell back up battery. > > unknown) One of the DS3231 parts, in a thermal enclosure that has a time > constant in excess of 24 hours. I think it's about the size you request. A > temperature sensor changes the divisor based on calibration data. Sort of a > doubly compensated device TTCXO or T2XO. I like this one for a > practical product. > > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.precisionclock.com > http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam > > ___ > 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] Manual Needed, TrueTime 800 series
Fellow clock-tickers, I have need of the equipment manual for a TrueTime 800 series TCG. More specifically, model 814-319-1. Worst case, I'll try contacting Symmetricom, but I'm not holding my breath on that one. Thanks. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?" ___ 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] xtal oscillator phase noise
AFAIK, in a crystal oscillator specifically (not oscillators in general), the oscillator transistor has almost nothing to do with either close in or far out phase noise. The close in phase noise is typically limited by the crystal's intrinsic noise and the far out phase noise is limited by the buffer amplifier, assuming you take the output through the crystal as is done in the 10811. Certainly in the case of the 10811, the oscillator transistor (a selected 2N5179) is not a player in terms of noise. BTW, the selection is based on startup issues and has nothing to do with noise. The buffer amplifier transistor contributes shot noise, however this is determined by physics, not choice of transistor. So again, choice of transistor is irrelevent for noise purposes. You do have to worry about distortion in the buffer amplifier that can upconvert 1/f noise. This can possibly require transistors with constant beta vs collector current, depending on the circuit design. Rick Karlquist N6RK Grant Hodgson wrote: > Henk > > Two things will dominate if you want such a low phase noise spec.:- the > loaded Q of the oscillator circuit, and the flicker corner frequency > of the sustaining amplifier transistor. To get a high loaded Q you need > a crystal with a high unloaded Q - maybe 100 000 or more - this isn't > difficult to achieve from a good crystal manufacturer, but you can't > expect any old crystal to work. And the rest of the oscillator circuit > should not load the crystal too much, otherwise the loaded Q, and thus > phase noise, will suffer. Good crystal manufacturers will provide the > necessary measurements of series resistance, motional inductance (or > capacitance, or unloaded Q - doesn't matter which) and static > capacitance. Lesser crystal manufacturers - don't. > > Also the flicker corner frequency of the transistor needs to be as low > as possible. Generally speaking, at offsets below the flicker corner > frequency you will get 30dB/decade, above the flicker corner frequency > you should get 20dB/decade, or flat, depending on the level of the phase > noise floor. If you can find a transistor with a lower corner > frequency, the flicker noise will be reduced. In fact, this is one of > the dominant parameters when choosing a transistor as an oscillator - > any old transistor can be made to oscillate, but to do so with a low > flicker corner frequency is not so easy, and the corner frequency is > usually a function of bias current. > > At 11MHz, most crystal oscillators use parallel resonant crystals, > although some are series resonant, such as the excellent Driscoll > oscillator which is capable of the performance you desire with a > suitable crystal. > > Then you have the added problem of the FSUP. It's a superb instrument, > but it has it's limitations. The FSUP data sheet states a phase noise > spec. of -130dBc at 10Hz offset for a 10MHz signal, which gives a > resulting sensitivity of -127dBc - 3dB worse than what you are trying to > achieve. You would need option B60 (cross correlation) to significantly > reduce the effect of the internal source by (say) 15db or so. > > regards > > Grant > > Henk wrote :- > Hello, > > Some questions on xtal oscillator phase noise. Attached the > measurement result of my series resonant xtal oscillator. > It is a class A, ibias 5 mA, Ixtal 1 mArms. Transistor selected for > low Rbb' 20 Ohm, Ft 100MHz. Reference voltage 5V from an ADR445, > filtered with 10uF folie cap. Phase noise target -130dBc at 10Hz. > > 1. Is series resonant better or easier to engineer than parallel > resonant? > > 2. Where should I have 20 dB/decade and where 30 B/decade? > > 3. Some suggestions for the next 25dB? > > 4. Is there more to learn from the attached picture? > > regards, > > Henk > > ___ > 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] XRPU hardware on the current marketplace
From: Bo Granlund <[EMAIL PROTECTED]> Subject: Re: [time-nuts] XRPU hardware on the current marketplace Date: Sun, 30 Dec 2007 18:08:33 +0200 Message-ID: <[EMAIL PROTECTED]> Hej Bo! > > I'm very interested in this area, but haven't actually done anything beyond > > surf the web looking for something that fits my budget and interests. > > > > I think a major part of the problem is that bleeding edge silicon > > technology > > as used by up-to-date FPGAs doesn't fit with 5V PCI. (The specs call for > > 11V > > spikes when the reflections are out to get you.) > > > > Most PCs have 5V PCI slots because most PCI add in cards are keyed for 5V > > slots. I haven't seen any motherboards with 3V only PCI slots, but maybe > > I'm > > not looking in the right place. In any case, I haven't seen any Xilinx > > development boards setup for 3V only. Most boards use front-end chips. See below. > I'm not entirely familiar with the power consumption characteristics of > a FPGA, the ones I've dealt with have an power supply, and I haven't > even cared to look at them more deeply to find out what they eat in > essence. I'm not terribly experienced in the area of HDL > implementations, or even using the system as sone kind of time source. > I've found a company http://www.digilentinc.com/, that sells for a very > decent price FPGA development boards. You get just about everything but > the kitchen and sick with one of their products, for a very lucrative > price, but I'm quite unsure howto connect the development board to a PC. Have a look at MTE (http://www.mte-india.com) who has three boards for the PCI bus, all three use Xilinx FPGAs and have various amounts of goodies. I think the "General Purpose PCI board" fits your needs fairly well, with some additional interface hardware which should not too hard to acheive. The MTE boards do as suspected, use a PCI chip, they use PLX chips, which is fairly industry standard. > They have somekind of bus architecture as far as I can tell, but I have > no idea howto use it, my HDL skills are not that developed yet. And to > interface with the PCI bus is maybe a little bit out of the scope of my > personal knowledge, and the scope of this project I want to undertake. There are PCI blocks to pick up, or use a PCI frontend chip like the PLX and run of that local bus. The PCI bus is complex enought to be confusing unless you spend quality time with the PCI spec and the PCI book. > A Spartan-3 is perhaps a little bit too complicated for the particular > project I'm looking at. If I'm to understand correctly, PHK did his > thing on a much smaller FPGA. But I can't find the specifications of the > HOT-I board anywhere. I kindof hope that some of the wizards comes > around and enlightens us with his foresight. The thing is, the Spartan-3 is at the dirty cheap level so you will certainly get a very big bang for the buck, and almost any attempt for such a board will be a nice little field-trip on the level of offending the chip with the task. > I'm sorry for just babbling about things in general, but even a newbie > has to start somewhere and learn the ropes. > > warm regards, and have a happy new year, > Bo Granlund Happy New welltimed Year! Magnus ___ 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] RCC 8000
In a message dated 30/12/2007 17:45:51 GMT Standard Time, [EMAIL PROTECTED] writes: Yes , I tried RadioClocks UK but no helping hand...they offered if I ship the unit back to the factory, ??? they give a price for the conversion./ assume to expensive /... ??? I am living about 25km from DCF77 in Germany, so believe the receiver part is not a big deal, ??? but the "code " is different then MSF60 - Hi Ernie I have some paperwork on the RCC8000, part, if not all, of some sort of manual and perhaps some schematics too. If that sounds vague it's because it was sent to me a few years ago and soon ended up in storage. I didn't reply earlier as I couldn't find it at home, which means it's probably still buried in storage and I have no idea when I'm likely to find it. If nobody else has a copy, and you don't mind waiting, I'm happy to share what I've got. It might be soon, but it could be quite a wait. I have a couple of RCC8000s, also buried somewhere so it's a while since I've seen them too, but I suspect any difference, aside from a fairly minor retune of the receiver, is going to be in the firmware. Both mine are for MSF and I have no idea whether or not there will be any firmware information in the documentation I have. I know it'll be a pain if you're so close to DCF77, but I don't think it should be very difficult to knock up a reasonable antenna for MSF, which might make life a lot easier. 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] xtal oscillator phase noise
Henk Two things will dominate if you want such a low phase noise spec.:- the loaded Q of the oscillator circuit, and the flicker corner frequency of the sustaining amplifier transistor. To get a high loaded Q you need a crystal with a high unloaded Q - maybe 100 000 or more - this isn't difficult to achieve from a good crystal manufacturer, but you can't expect any old crystal to work. And the rest of the oscillator circuit should not load the crystal too much, otherwise the loaded Q, and thus phase noise, will suffer. Good crystal manufacturers will provide the necessary measurements of series resistance, motional inductance (or capacitance, or unloaded Q - doesn't matter which) and static capacitance. Lesser crystal manufacturers - don't. Also the flicker corner frequency of the transistor needs to be as low as possible. Generally speaking, at offsets below the flicker corner frequency you will get 30dB/decade, above the flicker corner frequency you should get 20dB/decade, or flat, depending on the level of the phase noise floor. If you can find a transistor with a lower corner frequency, the flicker noise will be reduced. In fact, this is one of the dominant parameters when choosing a transistor as an oscillator - any old transistor can be made to oscillate, but to do so with a low flicker corner frequency is not so easy, and the corner frequency is usually a function of bias current. At 11MHz, most crystal oscillators use parallel resonant crystals, although some are series resonant, such as the excellent Driscoll oscillator which is capable of the performance you desire with a suitable crystal. Then you have the added problem of the FSUP. It's a superb instrument, but it has it's limitations. The FSUP data sheet states a phase noise spec. of -130dBc at 10Hz offset for a 10MHz signal, which gives a resulting sensitivity of -127dBc - 3dB worse than what you are trying to achieve. You would need option B60 (cross correlation) to significantly reduce the effect of the internal source by (say) 15db or so. regards Grant Henk wrote :- Hello, Some questions on xtal oscillator phase noise. Attached the measurement result of my series resonant xtal oscillator. It is a class A, ibias 5 mA, Ixtal 1 mArms. Transistor selected for low Rbb' 20 Ohm, Ft 100MHz. Reference voltage 5V from an ADR445, filtered with 10uF folie cap. Phase noise target -130dBc at 10Hz. 1. Is series resonant better or easier to engineer than parallel resonant? 2. Where should I have 20 dB/decade and where 30 B/decade? 3. Some suggestions for the next 25dB? 4. Is there more to learn from the attached picture? regards, Henk ___ 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] RCC 8000
Hi Rob, Yes , I tried RadioClocks UK but no helping hand...they offered if I ship the unit back to the factory, ??? they give a price for the conversion./ assume to expensive /... ??? I am living about 25km from DCF77 in Germany, so believe the receiver part is not a big deal, ??? but the "code " is different then MSF60 Rgds Ernie. -Original Message- From: Rob Kimberley <[EMAIL PROTECTED]> To: 'Discussion of precise time and frequency measurement' Sent: Sun, 30 Dec 2007 5:36 pm Subject: Re: [time-nuts] RCC 8000 Made by Radio Code Clocks in UK (now called Time & Frequency Solutions www.timefreq.com ). MSF 60 KHz receiver. I'm sure they had DCF77 option. Have you tried Googling it? Rob Kimberley -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 30 December 2007 13:58 To: time-nuts@febo.com Subject: Re: [time-nuts] RCC 8000 Hi, I am looking a description/manual for Radio Clock? type RCC 8000 receiver... assume it is tuned ?60kHz . and should like to convert? to DCF 77..every advise is appreciated. Rgds, Ernie -Original Message- From: Ulrich Bangert <[EMAIL PROTECTED]> To: 'Discussion of precise time and frequency measurement' Sent: Sun, 23 Dec 2007 11:33 am Subject: Re: [time-nuts] HP 5370B question Bob, just for fun I run the same test with my SR620 counter with results VERY similar to your measurements. See the attached distribution. Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Mike Feher > Gesendet: Samstag, 22. Dezember 2007 12:41 > An: 'Discussion of precise time and frequency measurement' > Betreff: Re: [time-nuts] HP 5370B question > > > Bob - > > With most counters, I have found that running them at > slightly less than 10 MHz gives you an extra displayed digit > of resolution. If the "1" out of 10 MHz were to be displayed, > it would take up one more digit in the MSD position, leaving > you one less in the LSD position. Since the numbers are so > close anyway, if measuring for stability, I personally would > prefer that extra digit in the LSD position. Regards - Mike > > > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Robert E. Martinson > Sent: Saturday, December 22, 2007 1:57 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] HP 5370B question > > I ran my 5370B for one hour, counting its own reference with > a one second gate. The summary of the results are: > > min 999.99650 Hz > max 999.99963 Hz > avg 999.99796 Hz > median999.99787 Hz > > Per the manual's Performance Test 5 (page 4-12) the spec is > +/- 0.005 Hz. It would be nice if my average was > 10,000,000.000 HZ but?? From a Time-nuts thread of several > months ago, the adjustment for this result is very touchy and > it's likely you will make the result worse rather then > better. Since mine is in spec, I'll leave it alone. > > I have sent the graphical & raw data to Corby, if anybody > else is interested please advise me of your email address. > > Regards, > Bob Martinson, N1VQR > > > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of corby d > dawson > Sent: Wednesday, December 19, 2007 2:15 PM > To: time-nuts@febo.com > Subject: [time-nuts] HP 5370B question > > > Hi, > > Could a few of the 5370B owners connect the counters > reference output to its counting input jack and with a 1 > second gate let me know what the last 2 digits are doing? > > An earlier post implied that the last couple digits will > wander around due to the way its designed. > > I'd like to know what a couple different counters show to see > if that is indeed true! > > Thanks, > > Corby Dawson > > ___ > 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] RCC 8000
Made by Radio Code Clocks in UK (now called Time & Frequency Solutions www.timefreq.com ). MSF 60 KHz receiver. I'm sure they had DCF77 option. Have you tried Googling it? Rob Kimberley -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 30 December 2007 13:58 To: time-nuts@febo.com Subject: Re: [time-nuts] RCC 8000 Hi, I am looking a description/manual for Radio Clock? type RCC 8000 receiver... assume it is tuned ?60kHz . and should like to convert? to DCF 77..every advise is appreciated. Rgds, Ernie -Original Message- From: Ulrich Bangert <[EMAIL PROTECTED]> To: 'Discussion of precise time and frequency measurement' Sent: Sun, 23 Dec 2007 11:33 am Subject: Re: [time-nuts] HP 5370B question Bob, just for fun I run the same test with my SR620 counter with results VERY similar to your measurements. See the attached distribution. Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Mike Feher > Gesendet: Samstag, 22. Dezember 2007 12:41 > An: 'Discussion of precise time and frequency measurement' > Betreff: Re: [time-nuts] HP 5370B question > > > Bob - > > With most counters, I have found that running them at > slightly less than 10 MHz gives you an extra displayed digit > of resolution. If the "1" out of 10 MHz were to be displayed, > it would take up one more digit in the MSD position, leaving > you one less in the LSD position. Since the numbers are so > close anyway, if measuring for stability, I personally would > prefer that extra digit in the LSD position. Regards - Mike > > > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Robert E. Martinson > Sent: Saturday, December 22, 2007 1:57 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] HP 5370B question > > I ran my 5370B for one hour, counting its own reference with > a one second gate. The summary of the results are: > > min 999.99650 Hz > max 999.99963 Hz > avg 999.99796 Hz > median999.99787 Hz > > Per the manual's Performance Test 5 (page 4-12) the spec is > +/- 0.005 Hz. It would be nice if my average was > 10,000,000.000 HZ but?? From a Time-nuts thread of several > months ago, the adjustment for this result is very touchy and > it's likely you will make the result worse rather then > better. Since mine is in spec, I'll leave it alone. > > I have sent the graphical & raw data to Corby, if anybody > else is interested please advise me of your email address. > > Regards, > Bob Martinson, N1VQR > > > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of corby d > dawson > Sent: Wednesday, December 19, 2007 2:15 PM > To: time-nuts@febo.com > Subject: [time-nuts] HP 5370B question > > > Hi, > > Could a few of the 5370B owners connect the counters > reference output to its counting input jack and with a 1 > second gate let me know what the last 2 digits are doing? > > An earlier post implied that the last couple digits will > wander around due to the way its designed. > > I'd like to know what a couple different counters show to see > if that is indeed true! > > Thanks, > > Corby Dawson > > ___ > 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. More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.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] XRPU hardware on the current marketplace
Hal Murray kirjoitti: >> Has anyone built this kind of device from something else than the VCC >> HOT1 FPGA board? Is there some directly competing product that I >> should know about, or something like that? >> > > I'm very interested in this area, but haven't actually done anything beyond > surf the web looking for something that fits my budget and interests. > > I think a major part of the problem is that bleeding edge silicon technology > as used by up-to-date FPGAs doesn't fit with 5V PCI. (The specs call for 11V > spikes when the reflections are out to get you.) > > Most PCs have 5V PCI slots because most PCI add in cards are keyed for 5V > slots. I haven't seen any motherboards with 3V only PCI slots, but maybe I'm > not looking in the right place. In any case, I haven't seen any Xilinx > development boards setup for 3V only. > I'm not entirely familiar with the power consumption characteristics of a FPGA, the ones I've dealt with have an power supply, and I haven't even cared to look at them more deeply to find out what they eat in essence. I'm not terribly experienced in the area of HDL implementations, or even using the system as sone kind of time source. I've found a company http://www.digilentinc.com/, that sells for a very decent price FPGA development boards. You get just about everything but the kitchen and sick with one of their products, for a very lucrative price, but I'm quite unsure howto connect the development board to a PC. They have somekind of bus architecture as far as I can tell, but I have no idea howto use it, my HDL skills are not that developed yet. And to interface with the PCI bus is maybe a little bit out of the scope of my personal knowledge, and the scope of this project I want to undertake. The board PHK used seemed to be ok, and I would be thrilled if I could aquire one of them, since they seemed to be quite ok for the task ahead. It's not a matter of building your own soft core, a counter for the frequency normal and a latch, and a interface to the PCI bus which can be memory mapped so that any processor can, and probably will fetch the time in a manner that doesn't require any kind of locking for the resource in kernel. If I understand correctly, this is exactly how FreeBSD does things, and there is even the, or rather, there was even the xrpu.c driver in the source code, as late as 7-STABLE, according to the cross reference setup by Robert Watson it seems as if they've removed it in 8-CURRENT, which is sad. I don't know about the way things are done in Linux land, and to be honest, I don't care. It's not that it wouldn't be a great operating system, it's simply that FreeBSD is much nicer. > My straw man is to find an inexpensive board with FPGA and not much else that > will plug into a PCI slot. I'm expecting to have to build a small daughter > card with a few coax connectors, level converters and whatever. > > Maybe the right answer is to wait until cheap PC motherboards have > PCI-express slots. (Servers have already switched to PCI-Express.) > > The best I've found so far is a Spartan 3 on Raggedstone1 > http://www.enterpoint.co.uk/moelbryn/raggedstone1.html > But the connectors don't have any ground pins and there aren't any mounting > holes. > That seems very intresting, maybe it could be utilized to work for your application. What comes to daughterboards and such of your own design is rather scaring to me. I've done PCB design for something like a decade ago, and I didn't like it, it's just not my thing. But, if you ever do create an solution that I could etch myself and solder a bit of things on to the board, then why not, please do share your inventions with us. :-) A Spartan-3 is perhaps a little bit too complicated for the particular project I'm looking at. If I'm to understand correctly, PHK did his thing on a much smaller FPGA. But I can't find the specifications of the HOT-I board anywhere. I kindof hope that some of the wizards comes around and enlightens us with his foresight. I'm sorry for just babbling about things in general, but even a newbie has to start somewhere and learn the ropes. warm regards, and have a happy new year, Bo Granlund ___ 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] accurate portable time source
Brooke: Have you tried out your last idea at least in a test configuration? Ronald Message: 1 Date: Fri, 28 Dec 2007 15:19:49 -0800 From: Brooke Clarke <[EMAIL PROTECTED]> Subject: Re: [time-nuts] accurate portable time source To: Discussion of precise time and frequency measurement <> Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=us-ascii; format=flowed Hi Ronald: Here are a some of ideas for the heart beat for a LCD based clock like the ones I've been developing. Best) A Vectron EX-380 series Vacuum OCXO only draws 0.35 Watts and if the 5 volt version that's only 70 ma. So a single AA would have enough energy, three AAA Ni-MH would be great. That was the good news. The bad news is that they are made of unobtanium (i.e. very expensive or need to be bought in large lots). Good) An alternative is the DS3231. This is an advanced version of the DS32khz TCXO and is adjustable to 0.1 ppm using the digital serial interface. Provision for a coin cell back up battery. unknown) One of the DS3231 parts, in a thermal enclosure that has a time constant in excess of 24 hours. I think it's about the size you request. A temperature sensor changes the divisor based on calibration data. Sort of a doubly compensated device TTCXO or T2XO. I like this one for a practical product. Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam ___ 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] RCC 8000
Hi, I am looking a description/manual for Radio Clock? type RCC 8000 receiver... assume it is tuned ?60kHz . and should like to convert? to DCF 77..every advise is appreciated. Rgds, Ernie -Original Message- From: Ulrich Bangert <[EMAIL PROTECTED]> To: 'Discussion of precise time and frequency measurement' Sent: Sun, 23 Dec 2007 11:33 am Subject: Re: [time-nuts] HP 5370B question Bob, just for fun I run the same test with my SR620 counter with results VERY similar to your measurements. See the attached distribution. Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Mike Feher > Gesendet: Samstag, 22. Dezember 2007 12:41 > An: 'Discussion of precise time and frequency measurement' > Betreff: Re: [time-nuts] HP 5370B question > > > Bob - > > With most counters, I have found that running them at > slightly less than 10 MHz gives you an extra displayed digit > of resolution. If the "1" out of 10 MHz were to be displayed, > it would take up one more digit in the MSD position, leaving > you one less in the LSD position. Since the numbers are so > close anyway, if measuring for stability, I personally would > prefer that extra digit in the LSD position. Regards - Mike > > > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Robert E. Martinson > Sent: Saturday, December 22, 2007 1:57 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] HP 5370B question > > I ran my 5370B for one hour, counting its own reference with > a one second gate. The summary of the results are: > > min 999.99650 Hz > max 999.99963 Hz > avg 999.99796 Hz > median999.99787 Hz > > Per the manual's Performance Test 5 (page 4-12) the spec is > +/- 0.005 Hz. It would be nice if my average was > 10,000,000.000 HZ but?? From a Time-nuts thread of several > months ago, the adjustment for this result is very touchy and > it's likely you will make the result worse rather then > better. Since mine is in spec, I'll leave it alone. > > I have sent the graphical & raw data to Corby, if anybody > else is interested please advise me of your email address. > > Regards, > Bob Martinson, N1VQR > > > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of corby d > dawson > Sent: Wednesday, December 19, 2007 2:15 PM > To: time-nuts@febo.com > Subject: [time-nuts] HP 5370B question > > > Hi, > > Could a few of the 5370B owners connect the counters > reference output to its counting input jack and with a 1 > second gate let me know what the last 2 digits are doing? > > An earlier post implied that the last couple digits will > wander around due to the way its designed. > > I'd like to know what a couple different counters show to see > if that is indeed true! > > Thanks, > > Corby Dawson > > ___ > 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. More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.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.
