| 摘要 |
PROBLEM TO BE SOLVED: To provide a ring oscillator utilizing a standard gate such as a gate array. SOLUTION: The ring oscillator performs oscillation at desired oscillation period by serially connecting delay circuits 1-5 with selecting functions and NAND gates 6-10, and constituting a loop as a whole. The delay circuits 1-5 with the selecting functions are constituted of the NAND gates where the delay time is d, delay signals for the portion of a first or second delay time with the delay time of 2d as a unit delay time T, set both the delay times from external parts, respectively, and make a time difference between both the delay times be the power multiplication of 2 of the unit delay time T. Consequently, T×2<SP>n</SP>(n is an integer) can be set as an oscillation basic period, and also the oscillation period can be set in the range of T×2<SP>n</SP>to T×(2<SP>n+1</SP>-1). COPYRIGHT: (C)2009,JPO&INPIT
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