| 摘要 |
PURPOSE:To obtain the manual channel selection unit, by increasing the easiness for operation with the manual channel selection of rotary switch type and improving the tracking characteristics of reception frequency to the rotation of the switch. CONSTITUTION:At the cross point among the conductors K0-K3, and T1 and conductors T2-T4, not shown, the channel selection switch which is well known and various mode command switches, are provided. In the apparatus of this invension, the transistors TR1,TR2 are located at the upward and downward manual search command switch position. When the rotary switch RSW turns right by one step, the contact 14 is momentarily connected and the capacitor C1 is discharged via the seesaw switch SSW connected to the contact 22. Although the capacitor C1 is charged via the resistor R1 after that, the TR1 is on for the time of the time constant until the end of charging. Similarly, when RSW is turned left, TR2 is on. The conductors K0-K3,T1 are scanned with known method, the mode command is read out and used for channel selection operation. |
