[time-nuts] synchronizing a large number of weaklycoupled oscillators

Bob Camp lists at rtty.us
Wed May 12 16:14:50 UTC 2010


If the oscillators all lock to each other, then multiple oscillators don't
have any particular advantage. 

Let's assume you can isolate them so they don't lock to each other. If they
are all of similar construction in a similar environment, there is a very
real limit to the advantage you would obtain, no matter how many you have.
It turns out that's true at one level for simple crystal clocks, and at a
very different level for atomic clocks. 


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Eugen Leitl
Sent: Wednesday, May 12, 2010 9:21 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] synchronizing a large number of weaklycoupled

On Wed, May 12, 2010 at 06:03:11AM -0700, jimlux wrote:
> Eugen Leitl wrote:
> >Has anyone utilized a network of locally, weakly coupled
> >oscillator synchronization (a la 
> >http://www.projectcomputing.com/resources/sync/index.html )
> >for precise timekeeping purposes?
> >
> There was a discussion on this list about doing something like filling a 
> cavern with pendulums in this connection a couple months ago.

I was thinking about a large population of freerunning oscillators
coupled via RF (e.g. digital pulse radio). Basically a bit like WiFi radios
in line of sight, talking to nearest neighbors.
> Bob York at UCSB and Ron Pogorzelski, a recently retired colleague of 
> mine at JPL, hav done a lot of work with coupled oscillator arrays. 
> They're used as a way to do phased array antennas.  googling "coupled 
> oscillator array" will turn up many hits.

Thank you -- very interesting.
> Allan had a paper where he had 8 inexpensive crystals coupled with 
> mixers and a microcontroller.  I think it's called the Clever 
> Temperature Compensated XO or something like that.

Presumably, a large population of cheap coupled oscillators could be
rather accurate collectively.

Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
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