Design of three channel complementary filters as a weighted sum of allpass sections

The design of power complementary filters for multichannel sub-bands using a minimum number of allpass sections is investigated. In particular it is shown that three power complementary filters, for example a lowpass, a bandpass and a highpass combination, can be generated from two allpass filters. From a hardware design point of view, these new power complementary structures are desirable, because the actual number of filters to be implemented is comparatively small.