[vdr] Re: Seperation of sat clock code

[Carsten Koch <Carsten.Koch@icem.de>]

Sergei Haller wrote:
...
> because the times delivered by the NTP protocol have to be exact up to
> milliseconds (or even microseconds, I can't recall that right now)
> I don't know in which format the time is broadcasted in DVB streams, but
> assume as simple as "YYYY MM.DD hh:mm:ss" or something like that.
> 
> even more, the ntp protocol has to measure the (network) transfer time
> from the time server to the client. So in our case this would be the
> transfer time from the broadcasting server via the satellite in the sky
> and to the DVB card. I doubt it's possible to measure that. (again: to
> measure in milliseconds)

Both of that is true.

But: Even if we only get the seconds, I would assume that we either get 
them more than once per second or we get them at the moment when the
milliseconds are zero (plus network delays).
And: Isn't the network delay well-known? After all, the speed of light
is constant and the distance to the satllite is (roughly) constant as
well.

So maybe the idea to create a "satelite clock device" is not that
bad after all?

Carsten.