| 摘要 |
PURPOSE:To always secure a reception in the optimum reception state regardless of the reception mode, by switching the oscillation frequency of a local oscillator circuit in accordance with the switch of mode. CONSTITUTION:The mobile contact 6a of the reception band change-over switch 6 is connected to the fixed contact 6d at the side of a wide band. Interlocking to this connection, the mobile contact 14a is connected to the fixed contact 14b. Accordingly the voltage obtained at the sliding piece 12a of the half-fixed volume 12 is supplied to the control voltage supplying terminal 4p of the local oscillator circuit 4. Thus the intermediate frequency f1 of the reception signal delivered from the mixer circuit 3 is made to be identical to the central frequency f01 of the 1st intermediate frequency filter 5a. On the other hand, the mobile contact 6a of the reception band change-over switch 6 is connected to the fixed contact 6c at the side of a narrow band. Thus in the same way, the frequency f1 is made to be identical to the central frequency f02 of the 2nd intermediate frequency filter 5b. |
