Method of determining whether A-law or mu-law encoding is applied

摘要

A first transceiver transmits a set of test levels to a second transceiver though a communication channel in which one or more types of companding laws are used for line encoding. The second transceiver determines line encoding with, and conversion between, the companding laws present in the communication channel based on the received set of test signals. The set of test levels are signals having levels determined based on the difference between the normalized amplitude, vertex, or energy curves for the types of companding laws, with or without accounting for other sources of network distortion. A decision metric is also generated from the difference between the normalized amplitude, vertex, or energy curves for the types of companding laws. The second transceiver then compares a combination of the set of test levels that is received from the communication channel with the decision metric. Line encoding and encoding conversion in accordance with the one or more types of companding laws is detected based on the comparison with the decision metric.