Time counting circuit, pulse converting circuit and FM demodulating circuit

摘要

Provided is a time counting circuit which can measure the time taken from the rising edge to the falling edge of a pulse signal and the time from the falling edge to the rising edge thereof. The time counting circuit according to the present invention comprises a measuring circuit for measuring the time between either of the rising and falling edges of the pulse signal, and a pulse converting circuit for converting a pulse signal to be measured to a pulse signal having either of the edges in accordance with the rising edge of the pulse signal to be measured and having either of the edges in accordance with the falling edge of the pulse signal to be measured. The time between either of the edges of the pulse signal converted by the pulse converting circuit is measured by the measuring circuit. The time obtained by measurement is the time taken from the rising edge to the falling edge of the pulse signal to be measured or the time taken from the falling edge to the rising edge thereof.