[time-nuts] OT: xtal osc PN

[Magnus Danielson]

On 09/19/2010 08:23 PM, francesco messineo wrote:
> On 9/19/10, jimlux<jimlux at earthlink.net>  wrote:
>> francesco messineo wrote:
>>> Hi Mike,
>>>
>>> as I said, current plans are for a few frequencies in the 20-50 MHz
>>> range. The current project needs 20, 22 and 42 MHz oscillators.
>>>
>>
>>
>> But you're multiplying that up, it will be 20log(N) worse...
>
> no, I'm using these as LO for frequency downconversion. 48, 50, 70 MHz
> to 28 MHz in the first prototype.

If you use a 10 MHz OCXO as reference, you will have a 20*log10(50/10) 
and 20*log10(70/10) worse phasenoise shift, i.e. 13,98 dB and 16,90 dB 
higher phasenoise than the reference.

Cheers,
Magnus