An apparatus includes: a generation unit that generates a PWM wave based on a sound signal; and a processing unit that converts the PWM wave to a square wave. The processing unit includes: a first counter that determines a pulse width of the PWM wave; a comparison unit that compares a first difference value, obtained by subtracting the pulse width in a second cycle being a cycle immediately preceding a first cycle from the pulse width in the first cycle, and a second difference value obtained by subtracting the pulse width in a cycle immediately preceding the second cycle from the pulse width in the second cycle; and an output unit that outputs the square wave while switching a state thereof in a case where a sign of the first difference value changes from that of the second difference value.