[time-nuts] 5 MHz Frequency Doubler

wa1zms at att.net wa1zms at att.net
Thu Oct 26 20:49:44 EDT 2006


I do not have any specific phase noise numbers to offer,
but the spectral output is:

5MHz   -54dBc
10MHz  0dBc
15MHz  -65dBc
20MHz  -58dBc
25MHz  >-70dBc
30MHz  -60dBc

My application uses the 10MHz output to drive a
homebrew direct frequency synthesizer with output in
the VHF range, so >-50dBc was sufficient for me.

The design goal of the final RF signal was a phase locked
RF carrier on 241GHz. With a requirement for short-term
stability of a few parts in 10^13 for very narrow band
weak signal signal detection.

In short, an amateur radio contact was made over a 79km
path on 241GHz while using a pair of radios whose freq
reference was an ultra-low phase noise 5MHz OCXO on each

The phase noise of the RF system was good enough to allow
a 0.67Hz filter to be used in the RX chain and the 5MHz
oscillator was specified as such.

Even without directly measuring the phase noise degredation
of the multiplier, based on the result at 241GHz it cannot
be much more worse than 20Log(n), or 6dB in this case.

-Brian, WA1ZMS

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of SAIDJACK at aol.com
Sent: Thursday, October 26, 2006 7:05 PM
To: time-nuts at febo.com
Subject: Re: [time-nuts] 5 MHz Frequency Doubler

Hello Brian,

nice circuit.

Would you have phase noise info, and harmonic/ sub-harmonic  measurements

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