Signal distribution system

摘要

A head-end for a signal distribution system with selection facility, includes a matrix (8) and a multiplexer (12) connected thereto for forming a multiplex signal. The head-end further comprises A/D converters (4-1 to DELTA -N) for converting the wide-band input signals into digital signals prior to supply to the matrix. The multiplexer comprises two amplitude modulators (13, 14) for the mutual quadrature amplitude modulation of a carrier (17) by two digital signals, and a summing means (18) for adding a digital signal in the base band to the modulated signal. A signal receiver for one of the modulated signals comprises a synchronous amplitude demodulator (21) connected to a synchronized carrier source (20) and also comprises means for digital-to-analog conversion (24).