RC polyphase filter with flat gain characteristic

This paper proposes a design of RC polyphase filters with flat gain characteristics in the passband and equi-ripple ones in the stopband. The time constants of cascaded sections are given by an equation in explicit form. Resistances and capacitances for optimum filters are obtained by solving an equation which is a polynomial of only one unknown parameter. Design examples are shown and effectiveness of the design is confirmed from simulation results.