[BC] Changes in the Channels

[Hershberger, Dave]

WFIFeng at aol.com writes:
> What is the actual data pipe on a standard OTA HDTV signal?
> 
> Willie...

It is 19392658.459751111508300006702563 Hz (about 19.39 megabits) (564/313
times 1.539 GHz/143). This is the payload of an ATSC signal. It does not
include reserved bits, equalizer training sequences, field, frame, and
segment sync, etc. All of this is available for MPEG packets, with the bonus
that MPEG packet sync words don't use up any of this payload. The MPEG sync
is replaced with segment sync, which is not part of this payload capacity.
At an equivalent of two bits per trellis coded symbol, the raw capacity of
an ATSC channel is 21524475.524475524475524475524476 bits/sec (about 21.5
megabits). This includes syncs and other overhead.

There are some minimal requirements for PSIP and MPEG null packets. The
great majority of the 19.39 megabits is available for video & audio packets.
You can make some very good HDTV pictures with this capacity.

Dave Hershberger 
Principal Engineer 
AXCERA
Tel: 530-272-HDTV (4388)
Fax: 530-272-4505 
dhershberger at axcera.com <mailto:dhershberger at axcera.com> 
AXCERA. Axcessing the new era of digital communications. www.axcera.com 
960 McCourtney Road, Suite C, Grass Valley, CA 95949-7423