Transmission line repeater station - has amplifier in one direction to compensate for lost signal and amplifier in opposite direction to compensate for subsequent loss

摘要

The repeater amplifier station for a two-way transmission line has an amplifier (30) in one line, whose gain is controlled by a thermistor (31) heated by current from a current source (35). Control signals mixed with the transmitted signal amplified are filtered (32) rectified and used to control the current supplied by the current source. The filtered signals also control a second current source (42) controlling the gain of an amplifier (40) in the return line by way of a second thermistor (41) to amplify the return signal to compensate for subsequent line losses. control of the amplifier at the next station is reversed.