Pulse Echo Measurements Telephone and Television Facilities

Pulse echo measurements have been used on telephone and television facilities since 1940 to locate impedance irregularities and control quality in manufacture and installation. These sets send a pulse into a line and observe on an oscilloscope the echoes returned from irregularities. The shape and width of the pulse, the rate at which it is repeated and the pulse magnitude are important in determining the accuracy of the results and the requirements of the measuring apparatus. The ``coaxial pulse echo set'' is used for factory and field testing of coaxial cables. The ``Lookator'' was developed for use on much narrower band systems such as spiral-four field cable and open wire lines.