The use of a vestigially symmetric prototype for FIR filter designs

The vestigially symmetric prototype function with its continuous derivatives and continuous frequency function appears to hale superior stopband attenuation and similar passband performance as compared to the classical rectangular filter prototype for finite impulse response (FIR) filter designs. The vestigially symmetric prototype equations are given, and the implementation constraints are investigated. The rectangular and the vestigially symmetric prototype performances are compared. A filter specification potentially useful for compact disk applications are given. The “unwindowed” vestigially symmetric prototype performance is investigated for a given number of coefficients. A kaiser window is applied to the vestigially symmetric prototype to yield a solution to the CD filter problem. Finally, the effects of the number of coefficients used in implementing the filter is analyzed