[time-nuts] Power supply for time source concerns

[Poul-Henning Kamp]

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In message <1958104416.2586171.1577043445646 at mail.yahoo.com>, Taka Kamiya via t
ime-nuts writes:

> First question to the group is, how do YOU manage this problem?

It used to be that there were only one kind of switching power-supply: The noisy ones.

That is no longer true by definition, but there is no easy road to this particular Damascus.

I have had good results modernizing my HP5065A with a high end
DC/DC converter, in order to reduce the heat, and in this particular
case, improve stability:

	http://phk.freebsd.dk/hacks/HP5065A/20150930_dcdc/

Almost no switchmodes (AC/DC or DC/DC) are spec'ed to run into a
serious pi-filter, but so far I have never had problems with it.

The best way to find out if your filtering works, is to switch
the supply between lead-acid (possibly with a linear regulator)
and the switch-mode solution, and see if you can measure any 
kind of difference, be it frequency stability or noise spectrum.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.