Abstract: System for digitally converting baseband channel signals into a frequency-division multiplex signal. The system comprises at its input converter circuits by each of which the sequence of codewords of the digital signal which correspond to each signal to be converted is divided into two interlaced sequences. The two devices required for processing each of the two digital signals supplied by the input circuits in the form of converters are combined so as to use in cascade a Fourier transformation device, a set of arithmetic units in the form of digital filters and a time-division multiplexer which supplies the desired multiplex signal. Use: multiplex transmission of speech signals.

Abstract: This closed loop multiplex communication system uses a timing unit to establish a general multiplex format consisting of 1024 frames in a multiframe. Each subscriber station transmits one message bit per frame (i.e. 1024 message bits per multiframe), but transmits only 32 signalling bits per multiframe (i.e. the eight-bit non-message blocks in four corresponding frames).