[time-nuts] E1938A PN measurments

Ed Palmer ed_palmer at sasktel.net
Sun Sep 30 19:16:01 UTC 2012


Would this characteristic be similar across all 10811s or would there be 
as much unit to unit variation as there is for aging and Allan Deviation?

Ed

On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote:
> I recently modified an old 10811 to bring out the crystal
> leads on miniature coax (instead of having them connect
> to the oscillator circuit).  This allowed me to measure
> the crystal's inherent flicker noise of frequency.
> The measurements indicate that the 10811 phase noise out
> to at least 100 Hz is entirely due to the crystal.
> An interesting aspect of flicker noise of frequency
> is that Allan deviation is independent of tau.  Thus,
> just one number describes the crystal noise.
>
> Rick
>
> On 9/30/2012 4:44 AM, Bob Camp wrote:
>> Hi
>>
>> Close in, it looks like it's pretty much the crystal and the loading 
>> of the bridge oscillator.
>>
>> Bob
>>
>> On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist 
>> <richard at karlquist.com> wrote:
>>
>>> The E1938A uses a crystal that is basically the same as
>>> the 10811 crystal except that it is in a reduced height
>>> package.  However the phase noise is not as good as a
>>> 10811 due to broadband noise in the automatic frequency
>>> control circuit.  By the time I discovered this, it
>>> was too late to try to fix it.
>>>
>>> Rick Karlquist N6RK
>>> E1938A designer




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