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Chapter 2 - DTV Standards
For other standards not mentioned on this update, please consult the HDTV
Technology Review Report of earlier years.
For a complete coverage of DTV Standards, please consult the Industry Edition of
this report.
A-VSB - Advanced-Vestigial Side-Band
Nov 06
A-VSB is a DTV broadcast system for mobile purposes proposed to the ATSC in
December 2005. During 2006 Sinclair Broadcast Group, Samsung Electronics, and
transmitter manufacturer Rohde & Schwarz, joined efforts to successfully test DTV
mobile reception at highway speeds.
A-VSB is expected to be included in the Advanced Television Systems Committee
(ATSC) digital-TV standard by 1H07, and is backward compatible with 8-VSB the
current DTV terrestrial system.
A-VSB, was previously simulated at NAB in April 2006, using forward-error-correction
(FEC) “turbo-coding” for difficult signal environments, which used about one fifth of
the transmitted bits for the actual video, the rest was to provide robustness so the
signal is tuned well by the receiving device.
In other words, 1.5 megabits per second (Mbps) of transmitted signal would have
only 375 kbps of actual video. That number of bits is considered sufficient for small
devices such as cellphones and PDAs.
Sinclair’s Buffalo digital station, WUTV-DT, received a temporary license for the join
group to test A-VSB in a real-world environment, and it did successfully up to
150Mph using a Samsung YEPP portable digital media player to decode and display
the MPEG-4 video carried within the turbo-coded streams transmitted from a server
specially suited for the parallel transmission of 8-VSB and A-VSB.
CES 2007
Samsung announced A-VSB and did a demonstration at the show.
According to Samsung:
“The A-VSB technology eases synchronization of broadcast signal timing of different
towers in a Single Frequency Network (SFN). SFNs can improve broadcast quality
with higher uniform signal strength throughout a service area, even in locations that
normally would have their signals interfered with by obstacles such as hills or
buildings.”
“A broadcaster adds a specified Supplementary Reference Sequence (SRS) to the
transmitted signal. A-VSB receivers can use the SRS in order to remain “locked in”
to the transmission. This helps maintain reception of the main signal and extra
‘turbo’ signal(s) even when interference would normally disrupt a signal, like when
the signal is reflected from moving objects near the receiver. A-VSB also enables
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