Abstract: An investigation on staircase sine wave DC/AC inverter is described. The inverter is analysed and designed with Walsh function approach and vector summation scheme. The unique characteristics of walsh function make the inverter structure simplified and waveform quality improved, compared with those of the conventional inverter switch controlling method. The vector summation scheme makes the regulation and the automatic stabilization of the output magnitude easily realized. The system block diagram, the circuit of the switch transformer bridges, the concept of the software design and the test results of a 250VA laboratory prototype are given. The results are quite satisfactory.

Key words: Walsh function, electronics, inverters