Companding

In telecommunication, a companding is an operation in which the dynamic range of signals is compressed before transmission and is expanded to the original value at the receiver.

Note: The use of companding allows signals with a large dynamic range to be transmitted over facilities that have a smaller dynamic range capability. Companding reduces the noise and crosstalk levels at the receiver.

Source: from Federal Standard 1037C and from MIL-STD-188