Data equalization based on the constant modulus adaptive filter

Increasing use of digital transmission under a wide variety of propagation conditions has prompted continued investigation of equalization techniques. Certain RF propagation effects can limit the performance of conventional adaptive equalization algorithms that require local synchronization. Discussed in this paper is a "predetection" adaptive technique, i.e. one that operates with no initial synchronization requirements. An adaptive filter based on the Constant Modulus Algorithm has proven useful for equalization of severe channel distortion. Observations regarding the utility and limitations of this algorithm are presented.