Automatic balancing circuit for longitudinal transmission system

DETAILED DESCRIPTION In accordance with a first aspect of the invention, first and second signals transmitted and received over a telephone local loop are balanced in phase and amplitude, said first signal being coupled between a ring conductor of said telephone local loop and earth ground, and said second signal being coupled between a tip conductor of said telephone local loop and earth ground.
It is a feature of the invention that differences in phase and amplitude between said first and second signals are detected by apparatus coupled to said tip and ring conductors.
It is a further feature of the invention that programmable digital processing equipment, responsive to differences in phase and amplitude between said first and second signals, generates digital control signals indicative of said phase and amplitude differences.
It is a still further feature of the invention that apparatus responsive to said digital control signals equalize the amplitude and phase of said first and second signals.
It is another feature of the invention that said equalized first and second signals do not interfere with voice transmission occurring simultaneously over said telephone local loop.
These and other objects and features of the invention will be more fully appreciated from the following detailed description when taken in conjunction with the accompanying drawings in which: