a method and system process a signal for pwm modulation . an amplitude control signal adjusts the amplitude of an input signal , and an offset is added to the amplitude - adjusted signal to produce an offset - adjusted signal . the offset is selected according to the amplitude adjustment applied to the input signal . the offset - adjusted signal is pulse - width modulated the to produce a pulse - width modulated signal , and the pulse - width modulated signal is filtered to reduce high frequency components thereof .