| 摘要 |
PURPOSE:To set an AFC band at a proper fixed level regardless of the changeover of a band by varying the capacity of an AFC band setting capacitor in response to the changeover of the band. CONSTITUTION:When a band changeover switch 6 is turned off, tuning coils 4 and 5 are set in series to each other. A resonance circuit consists of a variable capacitor 7, capacitors 3 and 15 and an AFC diode 2. In this case, an AFC band is decided by those capacitors and the diode. When the switch is turned on, the resonance circuit is formed with the coils 4, the capacitors 7 and 3, the diode 2 and the capacitor 15. In this case, the capacitor 15 is grounded via the switch 6 and therefore the AFC band is decided by the capacitor 3 and the diode 2. Thus the AFC band can be set at a proper level regardless of the changeover of a band. |
