[time-nuts] Precision PC timing [was TEC party file format?]

Chris Albertson albertson.chris at gmail.com
Wed Jun 29 20:02:13 UTC 2011


It would be a simple experiment.  All you need is a known good square
wave oscillator that can produce a stable signal at RS232 voltage
levels.

Linus PPS comes with a test tool that will print the events like this


found PPS source "/dev/pps0"
ok, found 1 source(s), now start fetching data...
source 0 - assert 1186592699.388832443, sequence: 364 - clear
0.000000000, sequence: 0
source 0 - assert 1186592700.388931295, sequence: 365 - clear
0.000000000, sequence: 0
source 0 - assert 1186592701.389032765, sequence: 366 - clear
0.000000000, sequence: 0

The above test shows time of each event and the sequence number.

One would have to import this to a spread sheet or write software but
not hard core programming required

On Wed, Jun 29, 2011 at 12:19 PM, Scott Newell <newell at cei.net> wrote:
> At 02:14 PM 6/29/2011, Tom Van Baak wrote:
>
>> Out of curiosity, if anyone on the list has pointer to papers that
>> show actual measurements of desktop systems used as precise
>> timing devices let me know. Not external boxes or PCI cards, but
>> using the OS itself as a timer. I'm sure with care 1 us or even
>> 100 ns is possible. For example, how accurate is the best NTP
>> system? But this is still a thousand times more jitter than plain
>> logic circuits and a million times worse than specialized TIC's.
>>
>> Reply off-line, I know this is getting very off-topic.
>
> Please don't take that off-line!  I'd say this is pretty on-topic for
> time-nuts.  Maybe it just needs a different subject line.
>
> --
> newell  N5TNL
>
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-- 

Chris Albertson
Redondo Beach, California



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