Patent ID: 8401174
Filing Date: 2013-03-19
Classification: H04B,H04M

Abstract:
1. A method for minimizing echo return loss in a communications system, comprising: breaking the dial tone on an analog telephone line connected to a hybrid circuit having selectable impedance configurations and that interfaces a digital communications circuit and the analog telephone line and simulating balance impedances corresponding to selected impedance setting configurations within a filter connected to the hybrid circuit; after the telephone line is quiet, inserting a white noise signal as a test call through the hybrid circuit onto the analog telephone line corresponding to a selected impedance setting configuration; receiving the returned white noise signal from the analog telephone line through the hybrid circuit and measuring the echo return loss of the white noise signal corresponding to the selected impedance setting configuration; dropping the test call; repeating with multiple test calls each at a selectively different impedance setting configurations to obtain echo return loss measurements at each of the impedance setting configurations; determining an optimum impedance setting configuration based on the results determined from the different test calls; and applying the optimum impedance setting configuration to the hybrid circuit interface.