The use of the Walsh transform in DC-AC PWM waveform generation allows the calculation of the switching angles by means of linear equations which depend on the fundamental amplitude. However, when it is needed a wide regulation of the fundamental amplitude, conventional application of Walsh transform forces to switch among different equation sets, due to the range limitation of each one of them. In this paper it is described an advanced method to obtain the switching angles that permits full regulation of the fundamental amplitude, with only a switching interval vector, in single phase systems. The paper shows Matlab simulation results that proof the efficiency of the advanced method algorithm