GB1406309A - Multiplex systems - Google Patents

Abstract

1406309 Automatic control R C A CORPORATION 8 Dec 1972 [9 Dec 1971] 56655/72 Heading G3N [Also in Division H4] In a multi-plexing arrangement used for remote control in television studios, in addition to analogue controls [see Divisions H3-5] a number of switches e.g. 61 are provided at a central control station, each coupled to a corresponding input of a multi-plexer 60, which is driven over lines a, b, c from counter 30 coupled to sawtooth generator 22. The output from multi-plexer 60 is fed via line 62 to a second input of assignment switching modules 35 and thence over line 63 to demultiplexer 65 in the remote controlled apparatus. Each of the outputs of demulti-plexer 65, comprising a zero output or a train of pulses dependent upon the position of the corresponding switch 61 &c., is coupled to a corresponding monostable multi-vibrator 66 which stays in its triggered state so long as pulses are received, thereby producing a corresponding D.C. control output. Alternatively, a plurality of digital control switches 71 relating to mutually exclusive control functions may be connected via encoder 70 to multi-plexer 72, the output of which is directed to assignment switching module 35 and thence to demulti-plexer 73, which has coupled to each of its four outputs a separate monostable multi-vibrator included in module 74. The outputs from the monostable multi-vibrators are supplied to a decoder circuit 75 to obtain the plurality of mutually exclusive digital output control functions. Tally control. Monitor signals emanating from the remote location are applied to multi-plexer 80 and the multi-plexed signals thence over line 82 to assignment switching modules 83 which are coupled via line 84 to demulti-plexer 85. Each output of demulti-plexer 85 is coupled to a corresponding monostable multi-vibrator 86: when a pulse train is applied to it, this remains in its triggered state and biases a corresponding transistor 88 conductive, thereby energizing the corresponding indicator lamp 90. The sensitivity of the arrangement is increased by means of a resistor 89 which passes a standing bias current through lamp 90. Assignment switching modules. The modules 35, 83 allow control to be enacted at the remote point instead of at the central control position.