Re: [time-nuts] Super stable BVA Quartz resonators... BVA??
Boîtier à Vieillissement Amélioré This is another version, Enrico Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ 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] Cesium Oscialltors and Low Phase Noise Frequency Standard
Martyn, designing a Cs standard is not the job for a single man, yet I might help you to find frustrated scientists who worked on a Cs project (some 10 years ago I took a part in a project, designing damn impossible precision electronics). About the noise of your quartz oscillator, not bad. Yet: Oscilloquartz 8607 has -128.5 dBrad^2/Hz at 1 Hz offset, at 5 MHz, which scales to -122.5 at 10 MHz, thus -125.5 dBc. Off the shelf, may have some delay. Rakon has -132 dBrad^2/Hz at 1 Hz offset, at 5 MHz, which scales to -126 at 10 MHz, thus -129 dBc. Small production for space, not sure you can actually buy it. In your oscillator, is the power dissipated by the quartz of 40 microwatts? Can you send a spectrum? I am getting great fun in reverse engineering the oscillator noise. The noise I mean, not the oscillator. This takes some 40-50 pages of my forthcoming book on phase noise and frequency stability in oscillators. You can't enter an order number, you must wait for Cambridge University Press, which is a non-profit company. Cheers, Enrico On 6 Dec 2007, at 15:12 , Martyn Smith wrote: Hi, Is there anyone out there clever enough to design me a cesium frequency standard?? There's only two manufacturers that I know of and there's room for another supplier. Also you may be interested to read we have just developed what we believe to be the worlds lowest close-in phase noise 10 MHz oscillator. It makes -121 dBc/Hz @ 1 Hz. Noise floor is only -162 dBc/Hz at the moment, but we are working on reducing this a further 5 to 10 dB. Enter your order number here.. Best Regards Martyn This Email is from: Martyn Smith Precision Test Systems LTD Tel: +44 (0) 1245 329608 Email: [EMAIL PROTECTED] Web: www.ptsyst.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. Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ 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] Improving the stability of crystal oscillators
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Dear all, the major problem for the use of a Peltier cell with a quartz oscillator is that the cell maximum operating temperature is of the order of 80 degrees Celsius. This is due to the low melting point of the metal pairs suitable to produce the Peltier effect (reversed thermocouple). The resonator inversion temperature occurs at 70-80 degrees Celsius, depending on the cut angles. A more general problem is that a good temperature controlled oven has high thermal resistance, limited by the dissipation inside the oven. Unfortunately, the Peltier cell has low thermal resistance, which means poor isolation from the oven. This problem is made worse by the joule effect, which always go with the Peltier effect. For this reason, the temperature fluctuations of the Peltier heat sink tend to be larger than the environment fluctuations (unless you use water cooling!). Thus, the thermal fluctuations propagating through the Peltier cell tend to be an amplified version of the environment fluctuation. This phenomenon is dramatic when the Peltier cools down, and a minor problem when the Peltier cell heats up. Very best, Enrico On 13 Oct 2007, at 22:13 , Don Collie wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Has anyone concidered using a small Peltier pile to maintain the crystal`s temparature. I understand that these devices will heat or cool, so it would be possible to maintain the crystal temparature at , say, 25 degrees celcius, over a range of ambient temparatures [perhaps 0 to 70 degrees]. There would be several advantages in this approach. Cheers!,Don Collie jnr. ___ 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. Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ 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] Basic regenerative-divider questions
); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED] RETRY
Folks,
deep in my database, there is this reference
R.\ C.\ Harrison,
``Theory of regenerative frequency dividers using double balanced
mixers''
{\em IEEE Trans.\ on Microwawe Theory and Technology},
MTT-S Symp.\ Digest vol.\ 1, June 1989, pp.\ 459--462.
There, you can find some issues about the filter.
Keep the group delay small, otherwise the divider may
enter in chaotic regime.
A short description on where chaos comes from is found in
G.\ Immovilli, G.\ Mantovani
``Analysis of the Miller Frequency divider by two in view of
applications to
wideband FM signals''
{\em Alta Frequenza}
vol.\ 17 no.\ 11, November 1973, pp.\ 313--323.
Very best to all
Enrico
Enrico Rubiola
professor of electronics
web:http://rubiola.org
e-mail: [EMAIL PROTECTED]
FEMTO-ST Institute
32 av. de l'Observatoire
25044 Besancon, FRANCE
voice: +33(0)381.853940 (E.Rubiola)
voice: +33(0)381.853999 (switchboard)
fax:+33(0)381.853998
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[time-nuts] Loran-C
Dear all, the old good Loean-C is still alive, as I can see. There is a funny thing about the receiver. The case of loran signal is that of finding the zero-crossings in a very polluted signal. The receivers designed in the '80s use a 1bit ADC (hard limiter) sampling at some 10 MHz, and find the zero crossings through the statistics of 0s and 1s at the converter output. They identify the envelope (needed for the zero crossing at 30 microsec from the origin of the envelope) in this way. It has been demonstrated that in the case of detecting the zero crossings in highly polluted signals, if the hard limiter is used instead of the full resolution of an ideal ADC (infinite number of bits), the SNR is made worse by less than 2 dB. There are a few articles written by Durke van Viilligen, Delft University, somewhere between 1975 and 1980. On request, I can dig deeper in my memory and hard disks. Cheers, Enrico Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Administrivia: Message Sizes
John, for sure I'll post the files on my site. Apologizes. Enrico On 11 Apr 2007, at 17:30 , John Ackermann N8UR wrote: I've been getting a lot of notices lately that messages are being rejected because they exceed the list's 128kb maximum size limit. Now that we have over 400 subscribers, I really need to enforce that limit; otherwise, the server gets bogged down (it's trying to blast out 400+ copies of that big message). The ideal thing is to post the large file at a web or ftp site, and just link to that location in your message. If you don't have public storage available, I'm sure several of us here would be happy to host files on their site; I certainly will (within reason). Thanks, John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Delay Line Discriminator article
Dear all, I have developed a theory of the delay line. Using the Laplace transform of the phase, mathematics is amazingly simple. Pick up the article no.6 on http://rubiola.org/journal-articles/readme.html Very best,. Enrico On 11 Apr 2007, at 20:19 , Didier Juges wrote: I came across an old article on the Delay Line Discriminator for Phase Noise Measurements (Microwave Journal 1983). I don't think the theory has changed much since then :-) http://www.ko4bb.com/ham_radio/Manuals/3_GPS_Stuff/ DelayLineDiscriminator.pdf Didier KO4BB ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Gate propagation delay jitter
My friends, if you worry about jitter there is a trick: synchronize the signat to the clock with a D-type flip flop, just at the output. Maybe too trivial for you. E. Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Gate propagation delay jitter
Then we would need to know/measure the jitter of the retiming flipflop. Expected values microwave: -120 dBrad^2/Hz flicker, -150 dB white RF:-140 dBrad^2/Hz flicker, -150 dB white Use a double balanced mixer, traditional configuration. A correlation scheme is probably not necessary. On the understanding side, aliasing is the beast to kill. A logic gate shows a gain g0 (analog gain!!!) during the edges, for it behaves as a sampling system - increased noise bandwidth, due to aliasing. William Egan wrote an illuminating article, Transact. UFFC (1990 in my notebooks, 1992 in my memory, sorry) There appears to be little definitive published data on the jitter of various logic gates and flipflops. I know. Fred L. Walls did some work, proc. Freq. Control Symp, I don't remember when. Consequently a simple reliable method of measuring such jitter would be useful. See above Whoever has data, please send. Cheers, Enrico Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Standards for units
Dear all, I have read some weird discussion about measurement units. There is a wonderful book I come across, by Francois Caldarelli You may take a look http://rubiola.org/shared/caldarelli.pdf then it's up to you Best Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] phase noise and related stuff
On 31 Mar 2007, at 20:45 , John Miles wrote: So your low-noise DC amplifier paper from '04 is awaiting my attention PCB layout may be available (incl. gerber), if the technician has not lost the files! Cheers, Enrico Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] phase noise and related stuff
Dear colleagues, I am new in this community, so I wish to introduce myself. Born in 1957, built the first receiver at the age of 11 and realized immediately afterwards that that radio engineering is much easier than social relationships. Yet never got a call sign (shame on myself). Now I am a full-time academic in a government lab. Some 20 years ago I got a sort of mental illness compelling me to measure time-related noise (phase noise and so on) with the highest sensitivity and accuracy. This increased a lot my nerd index, already high at that time. I suspect that I am not alone. Well, I wish to inform you that most of my weird stuff is available on my web page http://rubiola.org and more recently also on http://arxiv.org. Best wishes to you all, Enrico Enrico Rubiola professor of electronics web:http://rubiola.org e-mail: [EMAIL PROTECTED] FEMTO-ST Institute 32 av. de l'Observatoire 25044 Besancon, FRANCE voice: +33(0)381.853940 (E.Rubiola) voice: +33(0)381.853999 (switchboard) fax:+33(0)381.853998 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
