| 摘要 |
PURPOSE:To constitute a frequency presetting device at low cost and reduce its secular change, and to vary a tuning speed continuously by leading a desired tuning voltage out by the charging and discharging of an integration circuit through the selection of the 1st of the 2nd switch circuit and supplying it to a voltage control channel selecting circuit. CONSTITUTION:When the switch part 61 of the 1st switch circuit 6 is pressed, the integration circuit 9 consists of a resistance part 62 and a capacitor 8 and a charging speed is set freely by varying pressing force and increasing and decreasing a resistance value. When the output voltage of this integration circuit 9, i.e. tuning voltage reaches a desired value, is held at it is by opening the switch part 61 and the tuning voltage is digitized by the voltage control channel selecting circuit 2 through the operation of an external switch 5 and stored in a memory circuit 3. When the tuning voltage is lowered, the switch part 71 of the 2nd switch circuit 7 is pressed and the integration circuit 9 is composed of a resistance part 72 and capacitor 8 and discharge to an earth terminal.
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