[time-nuts] Atomic clocks and Wassenaar agreement
BNeubig at t-online.de
Mon Aug 21 14:41:24 EDT 2017
the paragraph applies also to low phase noise crystal oscillators.
The limiting equation for phase noise stated in that section 3. A. 1. b. 10 reads as follows:
L(F) > -(126+20log10F-20log10f) for 10 Hz ≤ F ≤ 10 kHz
With f being the carrier frequency in MHz and F the offset in Hz
In the attachment I have added a chart showing the limits for 10 MHz and 100 MHz.
This equation is rather arbitrary and not conclusive, because it assumes a slope of the PN curve close to carrier of -20 dB/decade, while in reality it is -30 dB/decade. This means that even if you do not touch the limits very close to carrier, the real phase noise may intersect at larger offsets. If you look at the numbers, you can easily find that not only a few best in class OCXO will touch or crosss the limits, but many normal "industrial state of the art" OCXO nowadays will...
I have no idea, where I could place my arguments to advocate a change of this unrealistic regulation.
Indeed it may be good that not all customs officers are able (or have the time) to solve that equation.
Von: time-nuts [mailto:time-nuts-bounces at febo.com] Im Auftrag von Attila Kinali
Gesendet: Sonntag, 20. August 2017 12:08
An: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Betreff: [time-nuts] Atomic clocks and Wassenaar agreement
On Sun, 20 Aug 2017 08:50:59 +0000
"Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:
> >Bob your right its interesting that the sales locations are in China
> >and India. Perhaps a larger opportunity for a RB reference today.
> Could be because hydrogen masers are dual-use under the Waasenaar Arrangement ?
As far as I can tell, there is no explicit mention of atomic clocks. But the list of dual use electronics is long and broad.
E.g. Section 3. A. 1. b. 10. covers basically all low noise frequency sources. Including just a simple low-noise XO.
Does anyone have more specific knowledge?
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor _______________________________________________
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