[time-nuts] Low noise PLL for transceiver locking

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Feb 2 14:11:08 EST 2010

francesco messineo wrote:
> Hi Murray,
> On 2/2/10, Murray Greenman<Murray.Greenman at rakon.com>  wrote:
>> Frank,
>>   My suggestion would be to try injection locking, rather than a PLL. No
>>   change is made to the 22MHz and 42MHz oscillators, except to find a way
>>   to inject enough reference power to force them to lock to it. Injection
>>   locking works well with modest harmonic relationships, and gives good
>>   noise performance. The injection can be via a coupling link, or even at
>>   the cold end of an existing bypass capacitor. Narrow pulses often work
>>   best.
>>   I am confident that you could lock 22MHz to a 2MHz injection (divided
>>   from your 10MHz reference) if the 2MHz pulse was narrow enough and the
>>   22MHz oscillator sufficiently stable. 42MHz is more of a challenge - you
>>   might need a double-step, such as first locking 7MHz to 1MHz from the
>>   reference, and using that to lock 42MHz.
> I confess I've never heard about injection locking! Do you have any
> suggestion where
> to start from to learn about it?
> 73
> Frank IZ8DWF
You can start with the references listed at the bottom of the page:



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