[time-nuts] Low noise PLL for transceiver locking
Bruce Griffiths
bruce.griffiths at xtra.co.nz
Tue Feb 2 19:11:08 UTC 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:
http://www.ko4bb.com/~bruce/InjectionLocking.html
<http://www.ko4bb.com/%7Ebruce/InjectionLocking.html>
Bruce
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