The L3 Coaxial System: Equalization and Regulation

Equalization is the process of correcting system gain and delay deviations sufficiently to permit the satisfactory transmission of signals. Regulation refers to that part of equalization which, by automatic means, corrects for relatively rapid changes in transmission. In the L3 coaxial system the transmission of television signals through more than 1,000 amplifiers introduces relatively severe equalization and regulation problems. Compared to the LI system, the L3 system has nearly three times the bandwidth and over three times more stringent transmission objectives. Thus it has been necessary to devote considerable effort towards finding equalization methods that yield practical and economical solutions. In previous systems it has often been the practice to design the bulk of the equalization system after the completion of an initial installation and the determination of the deviation characteristics of the system. In order to expedite the introduction of the L3 system into the field, equalization study and planning were initiated at the very beginning of the development of the system. One of the design methods was to make highly detailed studies using relatively inadequate data in order to find the major problems. As the data improved the studies were likewise