[time-nuts] nubie querie

[Bruce Griffiths]

Plus the effect of a star quake when the crystalline crust rearranges 
itself.
Somewhat analogous to a crystal jump.

Bruce

Bob Camp wrote:
> Hi
>
> Then there's the phase noise of the pulsar "oscillator"  ....
>
> -------------------------------------
>
> For a simple crystal oscillator the two word answer might be "Leeson's model".  That of course is a cop out since it clearly defines multiple things that contribute to phase noise.
>
> Bob
>
>
> On Mar 5, 2010, at 9:39 AM, Richard (Rick) Karlquist wrote:
>
>    
>> Don Collie jnr wrote:
>>      
>>> I`m not sure that questions like these is welcome on this list, but here goes anyway : 1/ What are the the 10 sources of the most constant [invariant] frequencies known to man, in order of decreacing constancy? Four immediately come to mind.
>>>        
>> I vaguely remember reading that pulsars have some fantastic
>> stability like 1E-20.  I don't remember how they established
>> this.
>>
>>      
>>> 2/ What is the mechanism in an oscillator, that is responsible for phase noise? [In only one sentence please]
>>>        
>> Thermal (Johnson) noise in the resonator and thermal and shot noise in the active device.
>>
>>      
>>> If this is known, then it becomes easier to design low phase noise oscillators.
>>>        
>> Perhaps, but just knowing the mechanism doesn't tell you that the
>> phase noise is inversely proportional to loaded Q, which you would
>> also need to know to optimize phase noise.
>>
>>
>>      
>>> I hope you enjoy these questions,.................................Don.
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>
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