| 摘要 |
PURPOSE:To decrease the required number of preset control switches by coupling a change-over switch, which interblocks with another switch capable of stopping channel selection operation thereafter, with the preset control switches. CONSTITUTION:Terminal a-2 of change-over switch 18 is freed, middle point c-2 is connected to output terminal group 12 of channel-selecting LSI16 via channel selection switch group 13, and terminal b-2 is connected to input terminal 11 and one terminal of resistor 15. Terminal a-1 of the change-over switch interlocking it is connected to input terminal 8, middle point c-2 is connected to one terminal of preset control switch 1 and input terminal 10, and terminal b-1 is connected to input terminal 9, respectively. In this circuit constitution, input terminals which can be controlled by preset control switches 1 and 2 can be changed between connections of switch 18 with side (a) and side (b), and the control over four kind of preset modes is realized. In addition, when switch 18 is placed at side (a), the circuit extending from switch group 13 to terminal 11 is cut off. |
