| 摘要 |
PURPOSE:To obtain an automatic frequency controller(AFC) of quick lead-in by giving a processor two modes of a steady mode and a capture mode. CONSTITUTION:A judging means to judge whether the system is lock-on or lock-off is provided and when it is lock-off, the processor is operated so as to sweep a control voltage to a voltage control oscillator. Thus, whether the system is lock-on or lock-off is judged, when it is lock-on, a normal AFC operation is performed in the steady mode, when it is lock-off, the control voltage to the voltage control oscillator is swept in the capture mode and the quick lead-in can be attained. |
