[time-nuts] Injection locking interconnect

Magnus Danielson magnus at rubidium.dyndns.org
Thu Jun 28 23:55:14 UTC 2012


On 06/29/2012 01:37 AM, Jim Lux wrote:
> On 6/28/12 3:22 PM, Magnus Danielson wrote:
>> Bill,
>>
>> On 06/29/2012 12:07 AM, Bill Dailey wrote:
>>> Guys,
>>>
>>> I am looking for info on injection locking. I have been searching
>>> around for info. I found an article that probably answers my question
>>> but I can't get to it.
>>>
>>> http://www.oldcitypublishing.com/FullText/JAPEDfulltext/JAPED2.1fulltext/11-24pp%20GC05-06%20%28Rajput%29.pdf
>>>
>>>
>>>
>>> Can anyone give me a reference regarding the required
>>> interconnection? I understand the ho and why... I just am wondering
>>> how you make sure locking occurs in the right direction. In other
>>> words the target oscillator gets locked to the injected signal and not
>>> the other way around.
>>
>> If you have two oscillators of the same frequency, these may
>> injection-lock to each other, in which case the injection locking causes
>> mutual synchronisation, which is a little forgotten research field all
>> on it's own.
>>
>> This is a great starting point on injection locking that fellow time-nut
>> Bruce Griffith wrote and collected references for:
>> http://www.ko4bb.com/~bruce/InjectionLocking.html
>>
>
> I've always wondered about injection locking a 2.45 GHz oven magnetron,
> and whether you could use it to do something like FM. The magnetron is a
> pretty crummy source phase noise wise, but is that because of low Q (and
> the frequency is just unstable, which locking would help) or because the
> amplification mechanism is noisy (in which case locking doesn't help).
> That is, is injection locking more like a MOPA or a locked power
> oscillator.
>
> (we're talking oven magnetrons here, not radar magnetrons for doppler
> radar which are actually designed for injection locking, etc. )

I also noted that microwave ovens is matching up to the 2,48832 GBd rate 
of SDH STM-16, which is kind of interesting fact, since that also means 
that frequency synthesis is fairly well established. Using a 155,52 MHz 
or 622,08 MHz oscillator is all very standard stuff, and a nice 
intermediary frequency would be 19,44 MHz. All being off the shelf stuff.

The challenge would be to get a decent microwave input for injection feed.

Cheers,
Magnus



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