Methods for measuring electrical echoes under echo compensator operating conditions

Abstract

This paper is about possible methods for detecting and measuring the electrical echo parameters with echo cancellers in operation. This task could be important for identifying fraudulent calls to bank customers and other illegal activities involving telephones. Echo is a common interference in telecommunications systems, and echo cancellers are used to suppress it. They reduce the echo to a level imperceptible to the ear. Four methods are proposed that can allow for the acquisition and measurement of an echo signal, even with echo cancellers in operation.