[vdr] Re: Time jumps

[Florian Steinel <florian.steinel@t-online.de>]

Sergei Haller wrote:

>does someone have more information on the transmitted time stamp?
>
Do you mean
- PDC? ()
   (transmit hours, minutes seconds)
  (ETSI EN 300 231 V01.03.01)
- Teletext - E.14 Real-time clock Page Header Packets
  (transmit hours, minutes seconds)
  (ETSI EN 300 706 V01.02.01)
- SI TDT  UTC Time (Page 23 ff)
   (ETSI EN 300 468 V01.04.01)

> - which format does the time stamp have? does it include microseconds (I
>   doubt it makes sense to transmit them because of the different lengths
>   between the sat and the dish depending on the geographic location, but
>   who knows?
>
As for the above standards , no microsecs.

> - how accurate is the time stamp within one transponder?
>   does it jump back and forward?
>  
>
It should not, but how knows?
Someone with more knowledge should answere this.
Maybe mod dvbsak and monitor some Transponder?!

>one possibility would be to do the following:
>   if the system clock is off by at least XX seconds (what is a good
>   value? 2? 10? 20?), then set the clock, causing a time jump on the
>   system clock.
>   if the diff is less than XX seconds, use adjtime.
>
>with that, if one uses always the same transponder for time synching and
>the transmitted time is not jumping, after some while the system time
>should get more and more correct (like with ntp)
>
>c ya
>        Sergei
>  
>




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