A Digital Audio Transmission System Using Quadrature Modulation of the NTSC Television Carrier
Tsutomu Noda, Isao Nakagawa, Takatoshi Shirosugi, Keiro Shinkawa, Shigeo Matsuura · SMPTE Journal · 1990
A digital audio signal-transmission system, in which high-quality digital stereo audio is multiplexed in the video carrier using a quadrature modulation method, is proposed. This system is fully compatible with the NTSC terrestrial television system and employs three new methods to improve compatibility with the existing NTSC system: dicode modulation, line interleaving, and line-comb filtering. Theoretical analysis and experiments show the feasibility of this transmission system at a data rate of 850 kbits/sec and a multiplexing level of—26 dB.