[ntp:questions] Re: PCI add on oscillator
GDowd at symmetricom.com
Mon May 9 20:16:27 UTC 2005
Look at the refclock driver list. There are many add-in cards from
Meinberg, Symmetricom and others which are supported by refclock
drivers. These cards typically include a voltage-controlled crystal
oscillator and dac control circuit to provide much better stability than
your standard xtal as well a stratum 1 functionality with an attached
reference source (gps, irig, etc). But, it's all relative. Ntpd does
pretty well with drift compensation on a well-soaked box for short
intervals. How long to do you need to flywheel?
Many of the add-in cards have ovenized crystal options. If you move
into Vxi or VME space, you can even go atomic with Rubidium. If you
have the money, we can even provide a hydrogen maser. Unfortunately, it
won't fit in a pci slot.
If you want to go the other way, you might be able to tack in a
replacement RTC on your mboard. I think Dallas has a drop-in rtc with a
temperature compensated crystal.
Date: 09 May 2005 14:42:38 +0200
From: Ulrich Windl <Ulrich.Windl at RZ.Uni-Regensburg.DE>
Subject: [ntp:questions] Re: PCI add on oscillator
To: questions at lists.ntp.isc.org
Message-ID: <86r7ggmuyp.fsf at pc8032.rz.uni-regensburg.de>
Content-Type: text/plain; charset=us-ascii
Maybe ask the people at Meinberg; clocks are their business:
"Joshua Coombs" <jcoombs at gwi.net> writes:
> Given standard pc clocks are less than ideal, with wide drift, etc,
> does anyone make a good quality oscillator as an add in, say via PCI?
> Ideally something NTP could discipline, so one could build a PC that
> could serve reliable time for more than 5 mins if external time
> sources became unavailable. I believe I read an article by PHK where
> he built one for test purposes, the discussion of 500ns accuracy got
me thinking about it again.
> Joshua Coombs
gdowd at symmetricom dot com (antispam format)
Technologist, TT&M Div.
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