In this paper, the basic mathematical properties of an alternative Pulse Width Modulation (PWM) strategy are revealed. Specifically, it is shown that average voltage produced from the approximation of a sinusoidal signal's intervals by rectilinear segments can be successfully substituted by the average voltage of corresponding pulses. From this understanding, a method is proposed to apply PWM for the production of required sinusoidal signal. Both theoretical and simulated results confirming this understanding are presented.