Frequency Reference for NTP Use?
Tomasz Ciolek
tmc at dreamcraft.com.au
Sun Jul 14 00:37:30 EST 2002
But why? talk the csiro in Sydney. they have a cesium clck level2 and
level1 NTP master sites. Maybe they'll let you get a feed?
regards
TMC
On Sun, Jul 14, 2002 at 12:27:20AM +1000, Alex Satrapa wrote:
> On Saturday, July 13, 2002, at 10:06 , Brad Hards wrote:
>
> >A few seconds a month is probably going to require some kind of
> >temperature
> >stabilisation.
>
> When you move from temperature compensated oscillators to ovenised*
> oscillators, you move from 1 second/week to about 1 second/year
> stability. You also move from the order of $x00 to $x000.
>
> >Unless you are really concerned with GPS availability, I'd look for
> >a GPS with a 1PPS output.
>
> The catch is that such units are usually designed to be rack mounted,
> and they're usually in the order of $1500. My budget is significantly
> less than that.
>
> I'll probably try to read through the NMEA driver to figure out where it
> gets the second-edge from, and find some way of reducing the jitter -
> such as the first character in the stream, rather than the first
> character of the time stamp.
>
> The least expensive ovenised oscillator with 1PPS output I could find is
> about $4,500.
>
> According to the NTP server, the jitter on the processor clocks of my
> Pentiums is about 0.008ms. That may actually do for the meantime.
>
> Alex
> * When I first read through the xntpd documentation, I read this as
> oven-sized. Which isn't that far off, when you see the setups that some
> places have for their Campus' Master Clock.
--
Tomasz M. Ciolek *
* Everything falls under the law of change;
<tmc at dreamcraft.com.au> * Like a dream, a phantom, a bubble, a shadow,
<tmc at goldweb.com.au> * like dew of flash of lightning.
* You should contemplate like this.
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