| 摘要 |
PURPOSE:To attain the adjustment only when the adjusting personnel is going to adjust the frequency with its own will by providing a switch for preventing mis-operation in addition to a switch for channel preset and frequency fine adjustment. CONSTITUTION:A channel preset switch 5 using a 1-circuit switch is changed into that using a 2-circuit switch and a button 7 is provided further. Although the operation channel preset memory is applied by turning on the channel preset switch 5 is unchanged from a conventional operation, the circuit is not operated even when buttons 1, 2 are depressed singly at the picture receiving mode where the channel preset switch 5 is turned off. The circuit functions by applying the operation while the button 7 is kept depressed. Thus, a part of the function is improved in terms of the hardware without modifying the program software of a microcomputer 6 already in existing by adding the switch 7 to a part of a key matrix circuit in this way.
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