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Originally Posted by spiderplant
I can explain... On UK satellite, QPSK modulation is used. (Simplifying a little)each transmitted symbol carries two bits of data, so the bit rate is double the bandwidth.
See http://www.educatorscorner.com/media/AN_5965-7160E.pdf if you want to know a load more about this.
Thank you for the link.
I think the BSKYB HDTV trial will use up to 15Mbps, but I'm not certain.
Only if you use the same compression technology (e.g. MPEG-2). New technologies are on their way which will get higher quality from the same bitrate (eg. MPEG-4 and WMV9). |
Well compression is the key - analogue broadcasts are not compressed at all, therefore (with a good signal) provide the best quality. Digital TV
at present is analogous to MP3's, rather than CD's, as it is apparent that quality is lost. In fact the audio bitrate of didital TV is similar, or even lower than, a typical MP3.
Now if they do switch to Mpeg4, then so much the better - it's not exactly a new technology, and most of us have seen great quality XviD or DivX video. Suprised they did'nt switch to Mpeg4 ages ago. But even so, it is still a lossy compression. I'd like to see us moving forward, not backwards!
Pob!