Measurement of the Frequency Characteristics of an RC Polyphase Filter Using 4-phase Square Waves

Generally, it is required to apply 4 sinusoidal waves whose phase difference are 90 degrees to measure the frequency characteristics of an RC polyphase filter. On the other hand, it is known that the same result can be obtained by using 4 square waves generated by a simple digital circuit instead of sine waves. In this paper, first, its measurement method is briefly introduced. Second, the circuit design for its integration is presented. Finally, the layout design is shown, and validity of this work is conformed.