Invention Grant
US5422668A Television signal switching device for a cable distribution system 失效
用于电缆分配系统的电视信号切换装置

Television signal switching device for a cable distribution system
Abstract:
The invention relates to the selection of a source from a plurality of sources by means of shunt switches and series switches, which are respectively turned on and mined off, and vice versa. For access to, for example, four sources the device has two intermediate terminals B.sub.1, B.sub.2), one series switch (SE.sub.a, SE.sub.b) is arranged between the user installation and each of the two intermediate terminals, and each of the intermediate terminals is coupled to two sources (IN.sub.1, IN.sub.2 or IN.sub.3, IN.sub.4) by each time one series switch (SE.sub.1, SE.sub.2, SE.sub.3, SE.sub.4). Moreover, each source (IN.sub.1, IN.sub.2, IN.sub.3, IN.sub.4) is a.c. coupled to earth by a matching impedance in series with a shunt switch (Z.sub.1, SH.sub.1, or Z.sub.2, SH.sub.2, or Z.sub.3, SH.sub.3, or Z.sub.4, SH.sub.4). The device is used in CATV.
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