Communications echo suppression adaptive filter - blocks repeated control signals arising from interference in correlated quantities when consecutive values indicate change of sign

摘要

The adaptive filter, for suppression in communications, has its control signals derived from correlating either the outputs of the filter bank with the summation circuits output or outputs obtained from the summation circuit. - The repeated control signals caused by the effects of interference in the quantities being correlated are suppressed such that consecutive value of these control signals are suppressed such that consecutive value of these control signals are evaluated for changes in sign. If a change in sign is detected between consecutive signals then the filter's setting elements are blocked or at least change much more slowly than they would if there were no sign change (ie no interference).