Abstract: A method for correcting reciprocity error in two port network measurements, in which an iterative algorithm is used to obtain an optimal symmetric matrix approximation to a measured 2×2 reciprocal network. The algorithm smooths measured data to obtain a low noise floor on measurements related to mode conversion in cables and connecting hardware. A geometric interpretation is used to approximate a measured data vector with the closest vector which satisfies the reciprocity constraint. An initial point in the constraint surface (reciprocity manifold) is located, and another point which is a better approximation of the measured data vector which satisfies the reciprocity constraint is generated. By repeating this process, the closest point in the manifold is quickly located. This closest point defines a reciprocal matrix which can be used to estimate the actual device under test (DUT) parameters.

Abstract: A calibration procedure for correcting two port frequency measurements. Calibration standards are initially connected to port one of a network analyzer and individually measured. This process is repeated with port two of the analyzer. A jumper which is used to bridge ports one and two is then connected to port one. At the far end of the jumper, three references are sequentially connected and the combination of the jumper and the terminations are measured. The raw data measured thus far is then processed to extract the two port electrical parameters of the jumper. The measured jumper is then bridged between ports one and two, and a series of measurements are made. Using the known electrical characteristics of the jumper, an intervening network is completely characterized and the measured SM and actual SA parameters of any device to be tested are relayed.

Abstract: Disclosed is a circuit which permits transmission of broadband analog CATV video signals on unshielded twisted wire pairs. The circuit includes an autotransformer with a ground connection coupled to the node between two secondary windings. The two opposite ends of the secondary windings are coupled to a choke, which, in turn, is coupled to an isolation transformer with a center-tapped primary and secondary winding for shunting any remaining common-mode currents.