| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an automatic frequency control loop circuit capable of oscillating frequencies in a broadband with high precision. <P>SOLUTION: The automatic frequency control loop circuit includes: a clock oscillator which generates a reference frequency; a frequency synthesizer including a first frequency divider which divides the reference frequency in a first division ratio, a second frequency divider which divides an oscillation frequency in a second division ratio, a phase detector which detects a phase difference between a first divided frequency divided by the first frequency divider and a second divided frequency divided by the second frequency divider, a voltage controlled oscillator which generates the oscillation frequency in accordance with the phase difference, and a frequency converter which outputs an output frequency in accordance with an input frequency and the oscillation frequency; and a demodulator including an error detector which detects an error by comparing the output frequency with a setting frequency, an integrator which integrated the error, and a computing element which computes a control signal corresponding to an integration value of the integrator. The automatic frequency control loop circuit is characterized by correcting the error while changing the first division ratio and the second division ratio in accordance with the control signal. <P>COPYRIGHT: (C)2007,JPO&INPIT |
