[time-nuts] Low noise PLL for transceiver locking

francesco messineo francesco.messineo at gmail.com
Tue Feb 2 18:24:16 UTC 2010

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?

Frank IZ8DWF

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