DUPLICATE SYSTEM AND SIGNAL SYNCHRONIZATION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a duplication system that is operated independently of a scale of a clock skew between dual systems in a duplicate system that is operated by a clock step synchronously with a clock signal. SOLUTION: A flip-flop 30 fetches an input signal A at a leading edge of a clock A in this duplicate system. A flip-flop 31 fetches an output of the flip- flop 30 at a leading edge of a clock B and a flip-flop 33 fetches the output at a trailing edge of the clock B. A selector 41 selects an output of the flip-flop 32 in the case of an operating mode 0 or selects an output of the flip-flop 31 in the case of an operating mode 1 according to the mode depending on a magnitude of skew of the clocks A, B. A flip-flop 33 fetches the signal selected by the selector 41 at a leading edge of the clock B and provides an output of an output signal (A-B).