VOLTAGE/FREQUENCY CONVERTER AND USE THEREOF FOR LIGHT WAVEGUIDE TRANSMISSION SYSTEM

PURPOSE: To determine the duration of two square pulses even when the measured voltage is extremely low by extracting one signal to be integrated from a measuring voltage. CONSTITUTION: A switch 13 supplies a measured voltage to the first input 15 of a comparator circuit 16 at first position and supplies a reference voltage at second position. A switch 20 supplies a first signal to be integrated to the second input 26 of comparator circuit 16 through an integrator 22 at first position and supplies a second signal to be integrated at second position. The comparator circuit 16 generates a pulse dependent the measured voltage and that signal is controlled to set two switches 13, 20 at the first position when the voltage being supplied from the integrator 22 is equal to the reference voltage and at the second positron when the voltage being supplied from the integrator 22 is equal to the measured voltage. One signal to be integrated is then extracted from the measured voltage.