| 摘要 |
PURPOSE:To prevent unpleasant noise after the program ends by turning off or decreasing the voice when the image signals are not inputted to the television set in the receiving condition and by switching off the power supply of the set after the fixed time has passed. CONSTITUTION:When a power supply plug PU is inserted into a plug socket, first, a standby power supply 6 is operated, and a power-supply voltage is supplied to a shut-off circuit 9 and micro-computer for the channel selection. When the television is broadcasted, the shut-off circuit 9 detects the vertical synchronizing signal from a synchronizing separator circuit 4 and preserves a main power supply 8 to ON condition. When the television broadcasting ends, the vertical synchronizing signal will not come, and the shut-off circuit 9 discriminates this and sends out the muting signal to a voice signal circuit 2 and a color signal reproducing circuit 3 and does not cause the voice and sets the picture to the blanking condition. When the condition continues for the fixed time, the main power supply 8 is turned off. |
