Closed-form design of digital IIR integrators using numerical integration rules and fractional sample delays

In this paper, the numerical integration rules and fractional sample delays will be used to obtain the closed-form design of infinite-impulse response (IIR) digital integrators. There are two types of numerical integration rules to be investigated. One is Newton-Cotes quadrature rule, the other is Gauss-Legendre integration rule. Although the proposed IIR digital integrators will involve the implementation of fractional sample delays, this problem is easily solved by applying well-documented design techniques of the finite-impulse response Lagrange and IIR allpass fractional delay filters. Several design examples are illustrated to demonstrate the effectiveness of the proposed method.