Re: [time-nuts] Time-Nutters-- Adding Rubidium to a Thunderbolt...?

Probably the easiest solution would be to feed 1 PPS from the T'bolt into a full-featured PRS-10 Rb, then fiddle with the loop parameters in the PRS-10 to best suit your needs. Unfortunately, I'm told that most of the surplus PRS-10s have been stripped of this capability. But a new PRS-10 *does*

Re: [time-nuts] What is the BEST crystal?

I guess, this is the so-called "Essen ring" crystal Regards Bernd -Ursprüngliche Nachricht- Von: time-nuts [mailto:time-nuts-boun...@lists.febo.com] Im Auftrag von Bruce Griffiths Gesendet: Sonntag, 1. März 2020 02:33 An: Discussion of precise time and frequency measurement Betreff:

[time-nuts] Time-Nutters-- Adding Rubidium to a Thunderbolt...?

Hello, Time-Nutters-- Is it possible to add/combine/mate a rubidium osc to a Trimble Thunderbolt GPSDO? Have there been any examples of this that I could use as a guide? Thanks for any info/feedback on this!! Mike Baker Gainesville/Micanopy Florida USA ***

Re: [time-nuts] Synchronisation of crystal oscillators

Hi, On 2020-03-02 03:53, Richard (Rick) Karlquist wrote: > > > On 3/1/2020 5:58 PM, Alex Pummer wrote: >> don't forget the  oscillator is one amplifier with infinite gain on >> his own frequency >> 73 >> KJ6UHN >> Alex >> > > Actually, the closed loop gain is not infinite, rather it is whatever

Re: [time-nuts] Synchronisation of crystal oscillators

On 3/1/2020 5:58 PM, Alex Pummer wrote: don't forget the  oscillator is one amplifier with infinite gain on his own frequency 73 KJ6UHN Alex Actually, the closed loop gain is not infinite, rather it is whatever is needed to boost thermal noise enough to account for the RF output level. I

Re: [time-nuts] Synchronisation of crystal oscillators

Hi Well, there goes Barkhausen …. :) https://en.wikipedia.org/wiki/Barkhausen_stability_criterion Bob > On Mar 1, 2020, at 8:58 PM, Alex Pummer wrote: > > don't forget the oscillator is one amplifier with infinite gain on his

Re: [time-nuts] Synchronisation of crystal oscillators

don't forget the  oscillator is one amplifier with infinite gain on his own frequency 73 KJ6UHN Alex On 3/1/2020 2:46 PM, Richard (Rick) Karlquist wrote: On 3/1/2020 2:28 PM, John Moran, Scawby Design wrote: My apologies if this is slightly off-topic, but it does concern crystal

Re: [time-nuts] Synchronisation of crystal oscillators

Yes, oscillators that are harmonically related can indeed injection lock. I've done it in a project about 40 years ago. In your case, you need to avoid RF cross-coupling between the oscillators. This includes both electromagnetic coupling, "direct coupling" via use of a common power supply, and

Re: [time-nuts] Synchronisation of crystal oscillators

On 3/1/2020 3:03 PM, Hal Murray wrote: OTOH, if you carefully adjust a couple of HP10811's to zero beat, you will have to go to extraordinary measures to keep them from injection locking. A lot more than just running them on individual voltage How extraordinary? How likely are 2 GPSDOs

Re: [time-nuts] Synchronisation of crystal oscillators

rich...@karlquist.com said: > Injection locking requires that the oscillators be within each others 3 dB > bandwidth, or at least close to that. Oscillators on different nominal > frequencies are no problem (EG 3 MHz and 10 MHz). Will oscillators on integral multiples of some frequency lock?

Re: [time-nuts] Synchronisation of crystal oscillators

> So, my question is - will my row of low frequency crystals 'talk' to each > other and synchronise in their frequency groups as well? Remember that these > crystals are long thin bars of quartz - one of the 3,600Hz crystals being 2mm > square by 60mm long - so they will possibly vibrate quite

Re: [time-nuts] Synchronisation of crystal oscillators

Hi The correct answer is “that depends”. The quick answer is “probably will”. It depends on the Q of the parts (which likely is pretty low), the coupling (which will be pretty good), and the exact frequency of each unit (which is unknown). Setups like this have been known to lock up. Bob >

Re: [time-nuts] Synchronisation of crystal oscillators

On 3/1/2020 2:28 PM, John Moran, Scawby Design wrote: My apologies if this is slightly off-topic, but it does concern crystal oscillators. However, I then remembered Huygens's discovery that 1S pendulums mounted on the same wall, or beam, would synchronise and swing either in phase, or

[time-nuts] Synchronisation of crystal oscillators

My apologies if this is slightly off-topic, but it does concern crystal oscillators. I have a small collection of ancient crystals amassed over the past 50 years or so. Half a dozen are low frequency (3,600Hz, 10kHz, and 100kHz), long bar, crystals sealed into B7G vacuum tube bodies. I was

Re: [time-nuts] What is the BEST crystal?

Dana The text merely indicates that Tolansky and Bardsley obtained these images in 1948. The annular crystal was one of the NPL frequency standards of the time. However, given that the fringes are multiple beam fringes, a high reflectivity electrode must lie on the top surface of the ring.

Re: [time-nuts] What’s the BEST crystal?

Hello Jim >How does a CSO compare with a Mercury Ion clock - the latter does fit in >a satellite and is intended to replace the USO kind of function. The current CSOs can be surprisingly compact. I was visiting a university colleague who had recently bought one from Cryoclock for use in quantum

Re: [time-nuts] What is the BEST crystal?

Bruce, is there any text about the ring resonator which discusses the features in the interferogram? Also I'd be interested in the configuration of the electrodes. My present interpretation is that the vibratory resonance stems from contra-rotating modes each propagating around the ring, and

Re: [time-nuts] What’s the BEST crystal?

On 2/29/20 2:47 PM, Attila Kinali wrote: On Sat, 29 Feb 2020 17:01:27 -0500 Bob kb8tq wrote: Isn't that where "whispering gallery" modes come into the picture ? …… and done with sapphire. This is the real answer to “why is nobody going to do this?”. You already have something ( the

Re: [time-nuts] Frequency standards for different tau in Allen Dev measurement

Hi Backing up a bit: If you are going to measure something like a crystal oscillator against a PPS, you need to be careful of phase slip. The oscillator may be off frequency by many ns/s. Working out what happens as it crosses a 100 ns boundary is not as easy as one might think. In addition,

Re: [time-nuts] time-nuts Digest, Vol 187, Issue 41

. From: time-nuts on behalf of time-nuts-requ...@lists.febo.com http://lists.febo.com/pipermail/time-nuts_lists.febo.com/attachments/20200301/3c67c577/attachment.jpg> -- Subject: Digest Foo