To solve a defect that the signal estimation capacity of a delay judgment feedback type series estimator is deteriorated under a multi-pass distortion condition in which the power of a delayed wave becomes larger than that of a direct wave though the estimator is an excellent system as a system for estimating a transmission signal from a received signal receiving multi-pass distortion by the small quantity of operation.

The characteristics of the delay judgment feedback type series estimator are improved by canceling main delay wave components causing the deterioration of the characteristics by using a diversity receiving system.