Patent ID: 6560778
Filing Date: 2003-05-06
Classification: H05K

Abstract:
A tap device of a cable broadcasting system, comprising: a sealed housing comprising a pair of conductive first and second housing members having openings which can be engaged with each other, said first housing member being provided with a pair of input and output terminals for connecting the tap device to a transmission line leading to a terminal side from a center equipment of the cable broadcasting system, said second housing member being provided with a plurality of tap output terminals for branching and transmitting a transmission signal running through said transmission line to subscriber terminal devices; a directional coupler for connecting said input and output terminals, passing the transmission signals running through said transmission line, and branching a part of the transmission signals; a splitter for distributing the transmission signals branched by the directional coupler and transmitting the distributed signals to said tap output terminals; a plurality of relays for connecting/disconnecting signal paths leading to said tap output terminals from the splitter; a receiving circuit for taking in the transmission signals branched by said directional coupler and receiving a command signal superimposed onto the transmission signals and directed to the tap device from said center equipment; and a control circuit for driving said relays in response to the command signal received by the receiving circuit to control connected/disconnected states of said signal paths in accordance with a command from said center equipment, said directional coupler, said splitter, said plurality of relays, said receiving circuit, and said control circuit being housed in the sealed housing, whereina splitter substrate with said splitter and said relays mounted thereon, a control circuit substrate with said receiving circuit and said control circuit mounted thereon, and a directional coupler substrate with said directional coupler mounted thereon are arranged in order from said second housing member in said sealed housing, said plurality of relays are mounted, and grounding patterns for surrounding the relays and connecting portions of the relays and the tap output terminals on said second housing member are formed on the surface of said splitter substrate facing said second housing member, and partition walls for surrounding said tap output terminals and abutting said grounding patterns of said splitter substrate to separate said relays and the connecting portions of the relays and said tap output terminals are disposed on the surface of said second housing member facing said splitter substrate.