[time-nuts] NIST frequency doubler

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Jul 8 00:08:05 EDT 2007

Mike Feher wrote:
> Well, I guess that is according to NIST. I do not see how an active doubler
> can have lower noise than a passive one, especially when the original signal
> has already been degraded by 20log2, or 6 dB so the contribution of the
> doubler would not even be noticed unless the source was so much better.
> Regardless, an interesting observation, but I am skeptical. I have seen
> other stupid measurement procedures come out of these high ranking so called
> official institutions over the past 40 years. There are a couple I am
> fighting right now, one regarding measurement of AM/PM conversion and the
> other basing oscillator long time ageing on short term measurements. Regards
> - Mike 
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
However, it apparently makes a detectable (10x) improvement to the short 
term stability of an atomic frequency standard.
Diode frequency doublers do need an amplifier to produce a doubled 
frequency output at the same level as a JFET frequency doubler.


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