[time-nuts] Phase Noise of 74AC gates
bruce.griffiths at xtra.co.nz
Fri Feb 19 22:54:12 UTC 2010
Martyn Smith wrote:
> Hi All,
> I read Garry's email about using the 74AC04 as a distribution amplifier.
> Did I read it right, does Gary say you will get -178 dBc/Hz at 10 kHz
> Being one of only 3 or 4 companies in the world that manufactures
> distribution amplifiers that break the -170 dBc/Hz region at 10 kHz
> offset, in my experience any logic gate or Op amp will limit you to
> about -155 dBc/Hz at offsets of 10 kHz and beyond.
> I've tested many competitive units and very few people get below -155
> I'm not about to say how we achieve -170 dBc/Hz phase noise, but we
> definitely don't use op amps or logic gates!!
Yes the claimed phase noise for the 74AC04 inverters is about 20dB lower
than the literature would suggest.
There's probably some problem with the measurement setup.
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