An Improved Method for Analyzing Compensating of Group Delay Variations in Broadband Satellite Signals

摘要

Group Delay Variations (GDV) versus frequency is an essential factor which causes distortion and degradation in wideband satellite signals specially when using phase modulation and high data rates. In this paper, transmission line is analyzed as a dispersive medium and some kinds of coaxial cables such as RG58U, RG59U, RG213 and ECOFLEX15 are compared as GDV parameter point of view. Then the effect of reflections from discontinuities and impedance mismatches at transmission lines, on GDV quantity, is investigated by suggesting a novel network model of transmission line with discontinuity or impedance mismatch, and extracting a new formula for GDV. Graphical data are presented based upon the formula developed, and the simulation results are also given by AWR software which confirms the theory and formula. At last, based on the developed formula, some calculations will be carried out both to predict the values of GDV parameter and to compensate it.