Structured LFT representation of digital LTI filters/controllers implementation as a graphic tool

As a powerful method in modeling parametric uncertainties, the Linear Fractional Transformation (LFT) scheme in this paper is extended to digital implementation of LTI filters/controllers. The convenient coordinate transformation and modification of digital operators can be easily represented under the proposed LFT interpretation. Moreover, a specialized descriptor system is deduced from this graphic representation, and a systematic procedure of implementation is presented. An example is also provided to illustrate this approach.