MICROTIME DIFFERENCE CIRCUIT AND TIME MEASURING CIRCUIT USING TWO PLLS

摘要

A microtime difference circuit and time measuring circuit enabling improvement of time resolution by one tenth or less are provided. The invention comprises a first phase-locked loop circuit having a voltage-controlled oscillator circuit generating a first oscillation frequency in response to a predetermined reference clock signal and a second phase-locked loop circuit having a voltage-controlled oscillator circuit generating a second oscillation frequency different from the first oscillation frequency in response to the same reference clock signal as the first phase-locked loop circuit. A microtime is obtained from the delay time difference between the output signals of the first and second phase-locked loop circuits.