| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a clock-supplying device, capable of preventing hits and omissions of an output clock at switching of input clocks and switching a present/preliminary system. SOLUTION: An input clock selection part 31 frequency-divides plural input clocks 101, and outputs a clock based on the clock selection signal 210. A variable frequency-dividing circuit 15 frequency-divides an output clock 141. A digital phase comparison part 32 phase-compares two input clocks, and digitally converts and outputs it. A digital phase control part 33 stores the output of the digital phase comparison part 32, and supplies it to the other system, and selects and outputs the output of the digital phase comparing part 32 or the stored output, based on the clock selection signal 210 and a system selection signal 110. A PLO part 34 outputs an output clock 141, which is phase-controlled by the output of the digital phase control part 33. A system-switching signal generating part 35 outputs a system-switching signal which is generated from the system selection signal 110.</p> |
