Abstract: An audio signal is multiplexed into a video picture signal by converting the audio signal into a sequence of digital code words from which subwords are extracted relative to a video signal line frequency. The number of bits in each subword is determined as a function of the amplitude dynamic range of the video signal, and each extracted digital subword is converted to provide analog samples with amplitudes proportional to quantizing of the corresponding digital subword. These analog samples are used to amplitude modulate an active portion of the video signal corresponding to a picture so as to provide a "composite" signal having the format of the video signal.

Abstract: The system comprises input modules (Pei) receiving entering packets, output modules (PSi) transmitting outgoing packets, a control memory (M) with double access and divided into routing modules (PTi, PAj), and a resource control module (GR).It also comprises an input time-division bus (BHDE) to connect timewise input modules (PEi) to routing modules (PTI, PAj) selected in the central memory (M) and an output time-division bus (BHDS) to connect timewise routing modules (PTi, PAj) of the central memory (M) to output modules (PSi). The control module (GR) is bidirectionally connected to the input modules (PEi) and to the central memory (MO through the input time-division bus (BHDE), on one hand, and to the output modules (PSi) and the central memory (M) by the output time-division bus (BHDS), on the other hand.