Function of OPTIMOD-TV: OPTIMOD-TV is an integrated signal-processing system which replaces conventional compressors, limiters, and clippers. It is an adaptation of the OPTIMOD-FM Model 8I00A to TV audio, and offers the TV broadcaster the same superb audio quality that has made the 8I00A so popular among FM radio broadcasters. Briefly, the OPTIMOD-TV system performs the following functions: 1. It rides gain over a range of as much as 25dB, compressing dynamic range and compensating for gain riding errors on the part of operators. The amount of dynamic range reduction ordinarily produced is adjustable. When OPTIMOD-TV is operated at its optimum release time setting, gain riding and compression are virtually undetectable because of advanced program-controlled time constants, level-dependent gating, and multiband compression. 2. It controls potential interference to video and/or future stereo services by means of bandwidth-limiting 15kHz lowpass filters incorporating full overshoot compensation. OPTIMOD-TV thus provides extremely tight control over peak modulation, preventing overmodulation and controlling its output spectrum simultaneously. 3. The OPTIMOD-TV compressor is a dual-band design which can be operated with the bands independent of each other ("independent"), or such that the bands are coupled and ordinarily track each other ("wideband"). When operated in "independent" mode, OPTIMOD-TV can make audio quality more consistent by correcting frequency balances between bass and midrange material. When operated in "wideband" mode, ‘ OPTIMOD-TV will preserve frequency balances and will produce an output which sounds like its input. k. OPTIMOD-TV prevents peak overload and overmodulation due to the effects of the preemphasis curve.