Design Equations for Jointly Optimized Frequency-Response Masking Filters

Abstract

The introduction of nonlinear optimization techniques to the design of a frequency-response masking (FRM) filter has changed the way in which an FRM filter is synthesized. It allows all subfilters in an FRM structure to be optimized jointly, resulting in further savings in the number of arithmetic operations. Under the joint optimization, a new set of design equations is necessary, not only for a more computationally efficient filter, but also for the simplification of the design process and the reduction of the design time. In this paper, we present a set of design equations that estimates the filter lengths and optimum interpolation factor in an FRM filter under joint optimization. It is shown, by means of examples, that the proposed design equations lead to a better estimation of the optimum interpolation factor compared with existing design equations.