Variable-magnitude filter design using simplified coefficient-transformation

In this paper, we present an improved method for designing a stable recursive variable-filter (VF) by utilizing a generalized transfer function as well as a simplified coefficient-transformation. The coefficient-transformation is introduced for guaranteeing the VF stability. The main advantages of this improved design are two-fold; one is that the utilization of the generalized transfer function makes the VF design more flexible, and the other is that the utilization of the simplified coefficient-transformation reduces extra computational burden needed in the VF optimization process. An example is given to illustrate that the improved method can get higher design accuracy than the existing method while offering the aforementioned two advantages.