Digital group demodulation systems for multiple QPSK carriers

A novel complex-input-complex-output transmultiplexer (TMUX) algorithm is derived with application to quadrature modulation schemes for use in the area of satellite onboard processing. The proposed approach exploits an inherent property of the all-zero lattice filters whereby two reverse polynomial all-zero filters are simultaneously derived. This property is coupled to a similar property requirement of the linear phase prototype filter-based doubly odd transform-polyphase filter TMUX, and the resulting computational load is analyzed for the European study concerning multiple carrier demodulation (MCD) equipment. The lattice subfilter algorithm offers a more robust solution to the transmultiplexer implementation than does the transversal scheme when fixed point digital signal processing is applied