A Class D amplifier receives an input signal and comprises a crossing detector and a signal generator that generates first and second periodic signals. Each period of the first periodic signal comprises first and second intervals, and each period of the second periodic signal comprises third and fourth intervals. The first periodic signal monotonically increases during the first interval and monotonically decreases during the second interval, the second periodic signal monotonically decreases during the third interval and monotonically increases during the fourth interval. The first and third intervals are substantially aligned, and the second and fourth intervals are substantially aligned. The crossing detector generates a first transition signal when a voltage of the first periodic signal or second periodic signal transitions in a first direction across a voltage of the input signal.