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October 26th 04, 04:51 AM

In article ,
Telamon wrote:
In article ,
(Mark Zenier) wrote:

Huh? There're no fast edges. It's a COFDM signal that consists of
hundreds of closely spaced subcarriers modulated as some slow baud rate
(around 30-50 Hz). It shouldn't slop over much, but it'll fill up all
the spectrum it's using. It's very similar to a FDM telegraph (Droning
DC-3) signal, only about 5-20 times as wide.

Mark Zenier Washington State resident

There are not hundreds of carriers. I believe the number is sixteen.

It is not the rate that they are switched at but how fast they actually
turn on and off. Think dV/dT.

The unfortunately vague article I found (Elektor Electronics, Dec. 2002)
said that the (sub)carrier spacing is 66.666 Hz, and that they use 64
QAM modulation. So there are somewhere around 160 subcarriers in a 10
kHz wide signal) and at 6 bits per baud the baud rate must be in the
20-40 Hz range. (As I understand it, the signal is around 40 kBPS).
(There's more tolerant form that uses 16-QAM).

Mark Zenier Washington State resident