Skip to main content

Effect of non-linear distortion in multi-channel amplifiers

01 July 1940

New Image

When the channels of a multi-channel carrier communication system are amplified by an amplifier common to the channels, distortion in the amplifier will cause new frequencies to be produced and these may appear as noise in the channels. This effect limits the relative level to which a specified amplifier can raise the combined power of a specified number of channels. A full discussion of the problem is given and curves are presented from which the power-handling capacity of an amplifier carrying many speech channels can be accurately determined. Separate treatments are given for the distortion caused by the near-linear part of the amplifier characteristic and that due to the discontinuity in the amplifier characteristic caused by anode current cut-off or grid current. Figures are given which enable the calculations to be based on the levels of harmonics produced by the amplifier when loaded with a sine wave of known power.