David L. Mills wrote:
> Danny,
>
> It doesn't stop working; it just clamps whatever it gets to +-500 PPM as
> appropriate. If the intrinsic error is greater than 500 PPM, the loop
> will do what it can with the residual it can't correct showing as a
> systematic time ofset.
>
> Dave
>
I didn
Danny,
True; there is an old RFC or IEN that reports the results with varying
numbers of clock filter stages, from which the number eight was the
best. Keep in mind these experiments were long ago and with, as I
remember, ARPAnet sources. The choice might be different today, but
probably would
Danny,
It doesn't stop working; it just clamps whatever it gets to +-500 PPM as
appropriate. If the intrinsic error is greater than 500 PPM, the loop
will do what it can with the residual it can't correct showing as a
systematic time ofset.
Dave
Danny Mayer wrote:
> David L. Mills wrote:
>
>
[EMAIL PROTECTED] (Danny Mayer) writes:
>Unruh wrote:
>> [EMAIL PROTECTED] (Danny Mayer) writes:
>>
>>> Unruh wrote:
Brian Utterback <[EMAIL PROTECTED]> writes:
> Unruh wrote:
>> "David L. Mills" <[EMAIL PROTECTED]> writes:
>>> You might not have noticed a couple of crucial
On 26 Led, 23:16, Unruh <[EMAIL PROTECTED]> wrote:
> David Woolley <[EMAIL PROTECTED]> writes:
> >[EMAIL PROTECTED] wrote:
>
> >> i would like to ask you for help or ideas with one ntp related task.
> >> I need to setup one ntp server to serve its sntp clients
> >> with time, which is specific amou
On Jan 26, 7:05 pm, [EMAIL PROTECTED] (Folkert van Heusden)
wrote:
> Hi,
>
> I would like to compare 2 NTP implementations. What would be the best
> way?
> I was thinking of configuring 7 upstream servers on these 2 physical
> servers and then on a third pc (which is also synced against these 7)
>
Unruh wrote:
> [EMAIL PROTECTED] (Danny Mayer) writes:
>
>> Unruh wrote:
>>> Brian Utterback <[EMAIL PROTECTED]> writes:
>>>
Unruh wrote:
> "David L. Mills" <[EMAIL PROTECTED]> writes:
>> You might not have noticed a couple of crucial issues in the clock
>> filter code.
> I d
[EMAIL PROTECTED] writes:
>On Jan 25, 12:53=A0pm, Unruh <[EMAIL PROTECTED]> wrote:
>> The Allan intercept is predicated on a very specific model of the noise in=
>> a clock ( as I recall basically random gaussian noise at high frequencies,=
>> and 1/f noise at low). It is not at all clear that r
[EMAIL PROTECTED] (Danny Mayer) writes:
>David L. Mills wrote:
>> Danny,
>>
>> Unless the computer clock intrinsic frequency error is huge, the only
>> time the 500-PPM kicks in is with a 100-ms step transient and poll
>> interval 16 s. The loop still works if it hits the stops; it just can't
On Jan 25, 12:53 pm, Unruh <[EMAIL PROTECTED]> wrote:
> The Allan intercept is predicated on a very specific model of the noise in
> a clock ( as I recall basically random gaussian noise at high frequencies,
> and 1/f noise at low). It is not at all clear that real computers comply
> with that.
Th
On Jan 26, 8:05 pm, [EMAIL PROTECTED] (Folkert van Heusden)
wrote:
> Hi,
>
> I would like to compare 2 NTP implementations. What would be the best
> way?
> I was thinking of configuring 7 upstream servers on these 2 physical
> servers and then on a third pc (which is also synced against these 7)
>
David L. Mills wrote:
> Danny,
>
> Unless the computer clock intrinsic frequency error is huge, the only
> time the 500-PPM kicks in is with a 100-ms step transient and poll
> interval 16 s. The loop still works if it hits the stops; it just can't
> drive the offset to zero.
>
> Dave
Yes, I f
David L. Mills wrote:
> It's easy to make your own Allan characteristic. Just let the computer
> clock free-run for a couple of weeks and record the offset relative to a
> known and stable standard, preferable at the smallest poll interval you
> can. The PPS from a GPS receiver is an ideal sourc
Hmmm it seems the problem is somewhat different:
- pc 1 has fine reception
- pc 2, both with on-board and external (= pci board with serial ports)
doesn't seem to receive even one single bit
I tested it by configuring a dcf-77 receiver in ntp on pc-1 (hbg is
dcf-77 protocol) and the same on pc-2
Anyone out there with an HBG (swiss time signal) receiver? Are you also
having very bad reception?
Folkert van Heusden
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Unruh wrote:
>
> He was refering solely to the NMEA signal not the PPS. Some GPS receovers
> have no pps.
In general those are not suited to accurate time transfer, and ones with
PPS cost a lot less than the the commodity car navigation devices,
because they don't have loads of map data (the pr
Folkert van Heusden wrote:
> I would like to compare 2 NTP implementations. What would be the best
> way?
The biggest problem is finding out the time on the machines without
using NTP. One approach is to use a simulator, but that assumes that
the simulator correctly represents clock imperfecti
>I am afraid I simply do not believe this. NMEA is lucky to get a ms not a
>usec. The offset on the NMEA should be a lot bigger than .001
The NMEA driver includes built-in PPS support.
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