An Extension of the Concept of Stop and Pass Bands of a Zobel Type Filter to a General Reciprocal Two Port Network Which has a Non-loxodromic Transformation (Correspondence)

The conventional treatment of the Zobel filter starts with symmetrical T or pi sections of pure reactance and then develops the iterative measures of the network; the fixed points and the propagation constant. It is shown that the propagation constant is either pure real (stop band) or pure imaginary (pass band). These iterative measures can be worked out for the general T section. Fig. 1 shows the nomenclature used for the symmetrical T section and the general two port.