A DSP-BASED MICROCOMPUTER SYSTEM FOR ECHO MEASUREMENT IN TELEPHONE NETWORKS

A schematic design is presented for a stand-alone test device to measu re all aspects of echo at the subscriber location of dial lines in tel ephone networks. The proposed architecture is based on off-the-shelf c omponents such as a general purpose PC and one of the available digita l signal processing (DSP) boards with minimum additional hardware. Ech o aspects are identified for measurements and the firmware (both hardw are and software) of the design are presented. Although specific hardw are components are chosen in the proposed system, the strategy of the design can account for different components. The system is tested in t he laboratory using a telephone channel simulator under different cond itions. It is also used in real telephone circuits. Samples of testing results are included.