Design of Efficient Polyphase Interpolated-FIR Filter Using Coefficient Symmetry

The finite impulse response filters have a linear phase response feature and are naturally stable. The fundamental disadvantage of these filters is that they need higher orders to produce responses of a similar size as infinite impulse response filters. Additionally, the complexity of the computations required to implement the filter is substantially larger, especially for filters with narrow transition bands. This study introduces a coefficient symmetric polyphase Interpolated Finite Impulse Response (IFIR) filter that is computationally effective. We give a mathematical formula for the intrinsic characteristics of the traditional polyphase structure in an IFIR filter. The multiplier units needed in polyphase IFIR filters can be cut in half using the proposed architectures. Using the proposed Type-1 polyphase IFIR structure, we also show how the decimator architecture works.