| 摘要 |
<P>PROBLEM TO BE SOLVED: To match clock phases between an active system and a standby system of a clock supply unit for supplying clocks being phase-coherent with a clock from an upper level. <P>SOLUTION: A clock supply unit includes: an active system clock supply unit 1a for outputting an active system clock being phase-coherent with a system clock; and a standby system clock supply unit 1b for outputting a standby system clock, and also includes: DPLL sections 2a, 2b for outputting clocks being phase-coherent with the system clock; variable delay circuits 4a, 4b for controlling the delay of the clocks from the above DPLL sections 2a, 2b; phase comparators 7a, 7b for comparing the phase of the active system clock for outputting via the above variable delay circuits 4a, 4b with the phase of the standby system clock; and phase comparison decision sections 5a, 5b for controlling the delay amount of the variable delay circuits 4a, 4b, based on the result of phase comparison between the active system and standby system clocks by means of the phase comparators 7a, 7b. <P>COPYRIGHT: (C)2008,JPO&INPIT |
