| 摘要 |
PURPOSE:To lower the cost of production by simplifying an AFC circuit by superposing an AFC voltage on a tuning voltage to be applied to an electronic tuner. CONSTITUTION:A tuning voltage, set by variable resistor VR1 or VR2, is applied to the base of transistor TR1 by being selected corresponding to channel-selecting IC1 and channel-selection switches SW1 and SW2 and then applied to series resistance circuits R2, R3 and R4 as an emitter-follower output. An AFC voltage, on the other hand, is inputted to terminal A and then applied as the emitter-follower output of transistor TR5 to sides of series resistance circuits closer to the earth. Then, voltages led out of sides of series resistance circuits farther from the earth are outputted to the electronic tuner. As a result, it is unnecessary to provide a tuning circuit for AFC in the electronic tuner. |
