| 摘要 |
PURPOSE:To enable accurate determination of a phase difference by giving a count start instruction to a phase difference detecting circuit at a time point when conversion of two voltage inputs into rectangular waves is started and a pulse from an oscillator is counted. CONSTITUTION:A phase difference measurement control circuit 96 starts to count the number of pulses from an oscillator 94 from a time point when it receives inputs from rectangular-wave conversion circuits 91 and 92, and gives a pulse count start instruction to a phase difference detection circuit 951 at a time point when counting is started for both of the circuits 91 and 92. After the counting is started, the circuit 951 once ends the counting at a time point when a rectangular-wave discordance signal from a discordance detection circuit 93 turns absent. Until the next count start signal is outputted from the circuit 96, the circuit 951 computes and outputs a phase difference with the number of counts at the time point of the end of the counting. Thereafter it is put in a state wherein a count value is cleared and a subsequent count start instruction is waited for. |
