[time-nuts] NIST frequency doubler

Mike Feher mfeher at eozinc.com
Sat Jul 7 23:52:34 EDT 2007

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

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Dr Bruce Griffiths
Sent: Saturday, July 07, 2007 11:10 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] NIST frequency doubler

Mike Feher wrote:
> Interesting. Diode doublers of this configuration have been around for
> 40 years, and of course so have their FET counterparts. While I never did
> investigation on any additive residual noise, since typically the 6 dB was
> enough to mask it, how is this better than the plain jane full wave diode
> doubler? 73 - Mike
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
It has lower phase noise especially at lower frequency offsets.
About 10-12dB lower (@75Hz offset, 10MHz input) than a typical frequency 
multiplier according to NIST.


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