Equalizing and Main Station Repeaters

The equalizing repeater is the most complex of the family of L-4 line repeaters; at least one is required in any line section longer than about 50 miles. A maximum of two equalizing repeaters can be placed between main station repeaters, which have a maximum separation of about 150 miles. The equalizing repeater contains all of the circuits found in a regulating repeater and thus provides, in part, the same features: the automatic gain correction required to track the cable loss variations with temperature and the fixed equalization required to compensate for the systematic or average component of the line repeater design error. The main additional function of the equalizing repeater is the adjustable loss required to compensate for the random component of design error, for the effect of temperature on the many line repeaters, and for the effects of aging. This is accomplished in the equalizing repeater by the A equalizer which includes six independently adjustable Bode-type equalizer networks whose several adjustable loss characteristics affect different parts of the L-4 transmission band. The §S9