[time-nuts] Phase Noise of 74AC gates

Bruce Griffiths bruce.griffiths at xtra.co.nz
Sat Feb 20 05:31:14 UTC 2010

Rick Karlquist wrote:
> Bruce Griffiths wrote:
>> He's made similar comments before.
>> It actually isnt that difficult to achieve an isolation amplifier phase
>> noise floor below -170dBc/Hz if one is careful to use appropriate parts,
>> design techniques, and the input signal level is high enough.
>> The real problem is verifying that performance.
> The 10811 production engineers searched for a long time for
> a low noise buffer amplifier and settled on the ANZAC AMC-123.
> The data sheet refers to a patent that reads like
> a construction article.  You can make your own if you can find
> an old 2N5109 transistor.
> Rick Karlquist N6RK
The Tyco/MAcom version of the AMC-123 datsheet doesn't refer to a patent.
Is a variant of a Norton CB transformer feedback amplifier?

One would need to cascade a number of these to achieve a reverse 
isolation of 120dB.
Whilst I dont have any 2N5109's,  I do have several 2N5943's.


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