16VSB
|
|
16VSB is an abbreviation for 16-level vestigial sideband modulation, capable of transmitting four bits (24=16) at a time.
Other slower but more rugged forms of VSB include 2VSB, 4VSB, and 8VSB.
16VSB is capable of twice the data capacity of 8VSB; while 8VSB delivers 19.39 Mbit/s (Megabits per second) in a 6-MHz television channel, 16VSB could deliver 38.78 Mbit/s, while making the sacrifice of being more prone to transimission error.
While 8VSB is the ATSC digital broadcast modulation format (used in the United States and a few other countries), 16VSB was planned for cable distribution. 16VSB is about twice as susceptible to noise, therefore less suitable than 8VSB for broadcast, but well suited to the signal-to-noise ratio of hybrid fiber-coax distribution, allowing twice as much programming in a 6-MHz channel.
However, as of 2004, cable companies have chosen to extend their existing quadrature amplitude modulation-based systems to carry digital television rather than adopting any form of VSB. This choice by the cable industry is one factor raised to explain the slow take-up of broadcast digital television in the U.S.