A design technique for linear-phase finite impulse response digital filters with constant passband amplitude

This paper describes a new design algorithm for finite impulse response (FIR) digital filters, which approximates constant passband amplitude and linear phase characteristics. The algorithm converts a filter's specification characteristic into a continuous impulse response by using the frequency response of a window function. The continuous impulse response is translated into discrete values to calculate tap-gain coefficients of an FIR filter. In this design algorithm, window functions belonging to the Hanning window series (such as the Harris' window whose characteristics are already known) are used. This design algorithm is an analytical design technique, featuring a filter length that can be decided when the specification is decided and does not require iterative numerical calculations to calculate tap-gain coefficients.