[updated:LAST EDITED ON 02-Apr-02 AT 10:14 PM (GMT)]Here you go W H, this'll explain it better than I ever could. It basically dictates the number of jets the signal is sent out in, the 8K is the more advanced technology and allows for more jets because of the more bandwidth on the carrier.
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(Coded Orthogonal Frequency Division Multiplex).
Digital transmission in a COFDM signal is low data rate QSPK or QAM modulation on carriers that are orthogonally spaced for minimum mutual interference. In 2k COFDM there are 1705 carriers and in 8k there are 6817 carriers. And MPEG-2 transport stream is fed to the transmitter where the coding and modulation take place. QSPK and QAM use both the amplitude and (I) and phase (Q) of the carrier to transmit the MPEG stream in the form of symbols. Using symbols and both the I & Q are forms of bandwidth conservation. It is important to remember that the real purpose of digital transmission is bandwidth conservation. One of the benefits is a consistent, high quality picture at all receivers above the minimum signal threshold. It is characteristic of an analogue signal to degrade gracefully, while a digital signal remains perfect until reaching the minimum threshold
http://www.digitaltv.com.au/dvbt.html
