By Alex Best, Cox Cable Communications
In August of 1982 the NCTA Engineering Advisory Committee, concerned about the capability of cable systems to provide quality transmissions of stereo audio, formed an ad hoc subcommittee to investigate multichannel television sound. In September of 1982 the subcommittee sent a report to the Chairman of the EIA BTSC committee outlining the areas of technical concern. The cable industry also went on record as being opposed to any of the stereo formats being proposed. The opposition centered on the selection of a subcarrier scheme (very similar to the 30+ year old FM broadcast system) at a time when digital audio systems were becoming widespread in the consumer marketplace. More important, there were cable carriage problems which were explained in detail in a report to the EIA BTSC committee. In March of 1983 the NCTA subcommittee wrote a comprehensive test plan and hired a test engineer to measure the impact of cable equipment on the proposed stereo systems. The testing was completed in September of 1983 and the results documented in a report titled "Multichannel Television Sound Report." As a result of the efforts of the cable industry, plus others, the FCC granted a "non must-carry" status to the newly selected stereo system in February of 1985. After the conclusion of the test report in 1983, the BTSC subcommittee entered a phase of providing a clearinghouse for inputs on both successful and unsuccessful attempts by the cable industry in providing quality stereo reception to our customers. As a result of this effort, one fact became evident. The cable industry needed a comprehensive set of measurement procedures and operating practices to verify optimum performance for stereo encoding equipment plus insure quality delivery through the remainder of the system. As a result the subcommittee reconvened its efforts in 1987. In November of 1988 a draft report on BTSC measurements and operating practices was presented to the NCTA Engineering Committee. What follows is a summary of that document.