| 摘要 |
PROBLEM TO BE SOLVED: To provide the frequency controller suitably for use with a broad band phase locked loop. SOLUTION: The frequency controller is provided with an oscillator 270, a mark or space counter 210, a frequency detector 220, and error signal calculation devices 230-260, 290, and controls the oscillator 270 so as to be resonated at a frequency substantially equal to a frequency of a received data stream. In this case, the oscillator 270 is a 4-phase ring oscillator that provides a clock signal subject to phase adjustment to the mark or space counter. Thus, the mark or space counter measures the length of the mark or space of the data with high resolution. |
