On Mon, 08 Dec 2003 10:17:44 +0000, The Natural Philosopher
wrote:



But the second point is I don't know what the modulation method is. I do
know that it invloves digital compression to get teh data rate down, but
how that data is encoded is not somethig I am aware of - however it
would seem strange indeed if it were done in such a way as to make te
signal peculiarly sensitive to low apmlitude time delayed analogues.
Ghosts. Given the amount of computing power and the bitrate, it would
alos seem that adaptive filtering to detect static ghposts and eliminate
them would in fact be pretty simple. So my guess is that digital signal
qre bothe encoded to elminintae ghost effects, and probably filtered to
remove even more - at leats in better designed sets.

There is compression anyway (MPEG-2 for the video) and forward error
correction. Modulation is Coded Orthogonal Frequency Division
Multiplexer (COFDM).


More that you ever wanted to know can be found by Google searching
using 'DVB-T' as a keyword.



The technology of all this gubbins has come on very fast with mobile
phones - fast and stable chips to do FFT stuff etc exist, and
de-ghosting is pretty much basic algorithims for DSP's.

..andy

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