| 摘要 |
PURPOSE:To simplify the device and automate switching by operating the 2nd switching operation when an emergency broadcast signal is inputted and projecting an emergency broadcast, and turning the 2nd and the 3rd switching circuits off and the 1st switching circuit on when the emergency broadcast control signal is ceased and projecting an original image. CONSTITUTION:When the emergency broadcast control signal (+B0) is inputted to a terminal 20, a transistor (TR) 17 turns on and a sufficient current flows to an emergency display element 3x, which turns on. When this TR17 turns on, TRs 11 and 10 turn off and a tuning voltage is applied to none of variable resistances 24a, 24b...24n for general broadcasting. At the same time, TRs 22 and 23 turn on, so the tuning voltage is applied to an emergency variable resistance 24x and then applied to an electronic tuner circuit 32 through a tuning voltage generating circuit 31. When an emergency broadcast ends, the TRs 17, 22, and 23 turn off and the TRs 11 and 10 turn on to make a return to a general broadcast reception state, so that a channel right before the start of the emergency broadcast restarts.
|
