[time-nuts] Synchronisation of crystal oscillators

[Richard (Rick) Karlquist]

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 out of phase and sometimes one would be stopped, by the minute interactions.
> 
> 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 vigorously compared w

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).  Even two "10 MHz" oscillators won't lock unless they
are adjusted to close to zero beat.  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
regulators.

Bottom line: probably not worth worrying about for your
hobby project.

Rick N6RK