Controlled carrier operation in a memory based echo cancelling data set

The author describes three methods used to achieve controlled carrier with different echo-canceling techniques and introduces a technique used in a memory-based echo canceler. Packetizing the data, special data patterns, and transversal filter structure are discussed as ways of implementing controlled carrier in echo cancelers. A block diagram of controlled carrier implementation in a memory-based echo canceler is shown. The memory-based echo canceler, which is presented in detail, can handle the highest data rate because it requires only one multiply/accumulate operation per sample for calculation of replicas and adaptation