Patent GB-1134722-A (GB)
Title: Selective switching network
IPC: H04B1/04
Filed: 1967-05-17
Abstract: 1,134,722. Television; magnetic storage arrangements. AMP Inc. 17 May, 1967 [8 June, 1966], No. 22908/67. Headings H3B and H4F. Relates to a switching arrangement for connecting a selected one of a plurality of signal input sources, e.g. video or audio signal sources, to a line or output bus, i.e. a programming console for a television studio. In the embodiment described, each pair of push-buttons in two rows of push-buttons 14, 15, Fig. 2, assigned Line and Preset functions respectively, is associated with a pair of video signal sources 61, 67 and a pair of audio signal sources 62, 68. The push-buttons control memory elements in video and audio matrix control units 43, 44 which operate switching modules in video and audio switch matrices 41 and 42. The memory elements are arranged in rows L/P and P/L to indicate that the Line and Preset control functions may be reversed in the different rows. The arrangement has output busses 25 and 26 for Line video and for Preset video, and output busses 27 and 28 for Line and Preset audio. Each of the output busses is routed through a transfer switch 33, 34 capable of switching the signals on one bus to the other bus. The transfer switches are controlled by relays 35 and 36 which are controlled by Take bar 16. When the relays are in the X and Y positions the inputs to the transfer switches on leads 37 and 38 are produced as outputs on Line busses 25 and 27 and the inputs from leads 39 and 40 are supplied to the output Preset busses 26 and 28. When the relays are in the #X and #Y positions the signals on the leads are switched so as to be reversed on the output busses. Depression of Line button 141 can be made to control either elements 46 or 47 and either elements 48 or 49. Similarly, the Preset button 151 can control any of these four memory elements. The switching modules 50, 51, 52, 53 are individually associated with a single memory element, e.g. 50 with 46. Which memory is operated depends on the logical state, X or X, Y or Y of the relays 35 and 36. Each memory is a bi-stable device and provides an output operating its associated switch module to its closed position to connect the associated video or audio input signal source to the appropriate bus. When cleared the memory element removes the signal source from the related output bus. Each memory element also operates a lamp associated with the push-button in the column common to such an element. Setting of selected memory elements is accomplished by a drive common to all memory elements of a given matrix control unit, e.g. drives 56 and 58 which are supplied by some clock source such as the vertical synchronizing pulse source. The arrangement includes push-buttons 17, 18 for video or audio only, Line and Preset video and audio monitors 19, 20, 22, 23, and a " mix " monitor (21, Fig. 1, not shown) which displays the mixed Line and Preset signal sources. The circuit in each of the units 43 and 44 is arranged such that depending upon the logical condition X or X, Y or Y, depression of either Line or Preset push-buttons may be made to control and set either one of the pairs of memory elements associated with the video and audio controls. Simultaneously, all of the memory elements in the same row with the element being set are caused to be cleared and the memory elements in the row containing memory elements which are not set are left undisturbed. The Specification includes description of a number of switching operations in which when signal sources have been selected by depression of a Line and Preset push-button the transmitted signal, i.e. the signal on the Line bus, is transferred to the Preset bus, and the signal on the Preset bus is transferred to the Line bus by momentarily depressing the Take bar 16. The memory elements are preferably multiaperture magnetic cores, Fig. 4, although they may comprise relay, transistor and vacuum tube memory elements. In the matrix control unit, Fig. 4, when switch 84 is momentarily closed by depressing push-button 141, pulses from driver 56 pass through the memory matrix to set memory 46, clear out the other memory in the same row and leave undisturbed the memory in the opposite row. If relay 35, i.e. contacts 91 and 94 are reversed, memory 47 is set instead.