Optimal Interpolated FIR (IFIR) Digital Filter Design with Spectral Estimation for Radar and Sonar System

Finite impulse response (FIR) filters are highly desirable in digital filter design because of their inherent stability and linear phase. However, when narrow transition band characteristics are required, they typically have a much higher filter order than their infinite impulse response counterparts with equivalent magnitude spectrums. Widowing methods and the frequency response sampling method were presented with examples, but they were improved upon with the IFIR design technique. The results shown that the computational cost of a Interpolated FIR (IFIR) is less with comparing the computational cost of a signal stage FIR filter and Multistage FIR filter which can be used both at the receiver and the transmitter.