Detektorvorrichtung zum Erfassen abnormaler Takte

摘要

Frequencies of clocks CLK1 and CLK2 are divided in frequency divider circuits (11 to 14), frequency-divided clocks CLK1A and CLK1B are input into clock comparators (15) and (16). Frequency-divided clocks CLK2A and CLK2B are input into clock comparators (15) and (16). The clock comparator (15) counts the number of pulses of the clock CLK1A based on the clock CLK2B and outputs an error signal ERR1. The clock comparator (16) counts the number of pulses of the clock CLK2B based on the clock CLK1B and outputs an error signal ERR2. An abnormal clock is detected by examining states of the error signals ERR1 and ERR2.