 Multi-channel, multi-octave multiplexers were investigated by Harold Schumacher at Microphase Corporation, and his results were published in 1976. The principle that multiplexer filters may be matched when joined together by modifying the first few elements, thus doing away with the compensating resonators, was discovered accidentally by E. J. Curly around 1968 when he mistuned a diplexer. A formal theory for this was provided by J. D. Rhodes in 1976 and generalised to multiplexers by Rhodes and Ralph Levy in 1979.
