“…3,9,11,12 In addition to, due to the absence of the external sampling signal (e.g., the clock signal in the SDM), the APWM output signal is modulated as a continuous time signal without producing the quantization noise. 3,[13][14][15] Because of this property, the APWM modulators have attracted a lot of attention for having an excellent SNR performance controller and they can be applied to convert a single-bit signal into a PWM signal which usually used in the control loop of the several power converting circuit. For example, they can be employed in inverter circuits, active filters, 14 class-D amplifiers, 16 Universal Mobile Transmitter Systems (UMTS), 17 ADSL/VDSL line drivers, 18,19 etc.…”