Function of OPTIMOD-FM: OPTIMOD-FM is an integrated signal-processing system which replaces conventional compressors, limiters, clippers, and stereo generators. Each part of the OPTIMOD-FM system has been precisely engineered to be compatible with all other parts to achieve optimum performance. OPTIMOD-FM should be fed unprocessed audio. NO OTHER AUDIO PROCESSING IS NECESSARY, OR DESIRABLE. Briefly, the OPTIMOD-FM 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-FM is operated with an optimum release time setting, gain riding and compression are virtually undetectable because of advanced program-controlled time constants and multiband compression. 2. It prevents aliasing distortion in the stereo generator by means of bandwidth-limiting 15kHz lowpass filters. Full overshoot compensation is provided for these filters. OPTIMOD-FM thus provides extremely tight control over peak modulation, preventing overmodulation and controlling the baseband spectrum simultaneously. 3. When OPTIMOD-FM's dual-band compressor is operated in "independent" mode, OPTIMOD-FM can make audio quality more consistent by correcting frequency balances between bass and midrange material. When operated in "wideband" mode, OPTIMOD-FM will preserve frequency balances and will produce an output which sounds almost precisely like its input. 4. OPTIMOD-FM prevents peak overload and overmodulation due to the effects of the FM preemphasis curve. 5. OPTIMOD-FM generates a stereo baseband signal with outstanding separation, low crosstalk, and vanishingly low distortion and spurious components.