By Thomas B. Keller, CableLabs
The FCC Advisory Committee's Planning Subcommittee Working Party 1 defined the attributes of high definition video. The Commission has placed a channel bandwidth limitation of 6 mHz for the terrestrial broadcasting system. Working Party 1 has described HDTV audio quality requirements as being CD like. The HDTV testing laboratory in Alexandria, Virginia is measuring only two-channel stereo systems. Many papers describing studies that compare two-channel and multichannel stereophony have been written by CBS in the U.S. [1], NHK in Japan [3], BBC in the United Kingdom [8], and IRT in Germany ( 7]. The studies agree that with two-channel stereophony the center signal (phantom or virtual) image is distorted by listening position. As screen size increases, the problem is exaggerated. All four organizations recommend that additional channels (speakers) are necessary to produce a stereophony image that can be viewed from a wide angle without distortion. This paper proposes that HDTV audio use a center channel to stabilize the audio image.