| 摘要 |
A satellite dish receiver system has a switch that fits onto an existing system to enable it to use a second LNB (low noise block) 4 for receiving signals other than those from the satellite at which the system is aimed. The switch is mounted at dish 1 level and derives its supply and switch information from the existing system using the system's co-axial cable. The switch has an artificial negative 5 volt rail provided by REG 1, and an artificially maintained positive rail to part of its circuit provided by C1. C2 and C3 provide switching pulse timing components. The arrangement allows the output signals from two satellite LNBs to be switched onto a single cable, using that cable as a switchover signal source and at the same time maintaining the normal variations in the supply to the two LNBs of 13 volts and 17 volts, whilst remaining latched in either set or reset mode. <IMAGE> |
