Field Guide · protocol

Also known as: ATSC 1.0, ATSC, 8VSB DTV

ATSC 1.0 is the first-generation digital terrestrial television standard of the Advanced Television Systems Committee, used for over-the-air TV in the United States, Canada, Mexico, and South Korea.1 Unlike the multi-carrier COFDM systems used in Europe, ATSC 1.0 transmits an MPEG-2 transport stream on a single carrier using eight-level vestigial sideband modulation (8VSB), protected by trellis-coded modulation and a Reed–Solomon outer code.

8 amplitude levels = 3 bits/symbol pilot 6 MHz VSB channel
ATSC 1.0 sends a single-carrier eight-level VSB signal with a small in-band pilot to aid carrier recovery.

Overview

8VSB maps three bits to each of eight amplitude levels at 10.76 million symbols per second, filling a 6 MHz channel and delivering about 19.4 Mbit/s of payload — enough for one HDTV program or several standard-definition subchannels. A small pilot tone near the lower band edge gives the receiver a reference for carrier recovery. The choice of a single-carrier waveform, rather than OFDM, was deliberate: it offers a higher tolerance to certain impulsive noise but leaves the receiver’s adaptive equalizer to fight the multipath that COFDM handles with a guard interval — the source of ATSC’s early reputation for difficult indoor reception.

Technical characteristics

Property Value
Modulation 8VSB (8-level vestigial sideband)
Symbol rate 10.76 Msym/s
Inner code 2/3-rate trellis-coded modulation
Outer code Reed–Solomon (207,187)
Interleaving 52-segment convolutional
Payload 19.39 Mbit/s MPEG-2 transport stream
Video MPEG-2 (H.264 for mobile ATSC-M/H)

History

The ATSC standard A/53 was completed in 1995 and adopted by the US FCC in 1996; regular broadcasts began in 1998, and the US analog shutdown followed in 2009.2 8VSB was selected over a COFDM proposal after a contested comparison, a decision that shaped a decade of receiver-equalizer research aimed at closing its multipath gap against DVB-T.

Deployment

ATSC 1.0 is the terrestrial DTV system of the United States, Canada, Mexico, South Korea, and a few other countries. It is now being overlaid and gradually succeeded by ATSC 3.0, an OFDM-based next-generation system, though the two are not backward compatible and 1.0 broadcasts continue during the transition.

Decoding it with GopherTrunk

GopherTrunk does not decode ATSC 1.0 — MPEG-2 television is far outside its land-mobile trunking focus. The 6 MHz 8VSB signal can be captured with a wideband software-defined radio and demodulated in purpose-built tools, but the channel is too wide for a narrowband RTL-SDR to take in at once. The modern successor is documented under ATSC 3.0.

Sources

  1. ATSC standards — Wikipedia, for the ATSC 1.0 system, its 8VSB waveform, trellis coding, and Reed–Solomon FEC. 

  2. A/53 ATSC Digital Television Standard — ATSC, the primary standard defining ATSC 1.0 modulation and channel coding. 

See also