Satisfying the Haar condition in halfband FIR filter design
Rashid Ansari · IEEE Transactions on Acoustics Speech and Signal Processing · 1988
A reformulation of the FIR symmetric halfband filter design problem is described that allows elimination of the constraints on coefficients from the design, thereby facilitating the direct use of the Parks-McClellan design procedure. In this procedure, it is only necessary to use a single-frequency care-band for approximation with about one-half the filter order of the halfband filter.>