(under the class definition) Systems including means for compensating for changes in the signal energy passing over a transmission line caused by changes in the line characteristics, wherein a control signal distinct from and in addition to the signal energy is also passed over the line to be influenced by the changes in line characteristics, the control signal being used to control the compensating means.
(1) Note. Systems for automatically compensating for changes in the characteristics of a transmission line where the carrier current of the transmitted energy is used to control the compensating means are classified in subclasses 17+.
SEE OR SEARCH THIS CLASS, SUBCLASS:
2+, for plural channel systems utilizing a pilot frequency.
15, for systems utilizing for a pilot line for control purposes.
17.1+, see (1) Note above.
SEE OR SEARCH CLASS 330, Amplifiers,
52, for amplifier systems having pilot signal control means. See Class 330, Class Definitions for the line between the two classes where such subject matter is involved.
379, Telephonic Communications,
338+, for repeater systems (e.g., two way amplifier system) which may utilize a pilot current to compensate for changes in the transmission characteristics of the main line.
