AUTOMATIC EQUALIZER

PURPOSE:To reduce the power consumption by detecting a time fluctuation of propagation distortion and its magnitude in a digital mobile communication, selecting an algorithm used for updating a tap coefficient of the automatic equalizer from the valve, decreasing the arithmetic quantity and decreasing the clock frequency of the processing unit. CONSTITUTION:A time fluctuation of propagation distortion and its magnitude are detected by using a propagation distortion detector 34 so as to monitor a difference between an output signal of a transversal filter 1 and an input signal 100 for a prescribed period. An algorithm with least arithmetic quantity and able to make sufficient equalization is selected from an update algorithm selector 5 according to the value and a tap coefficient updating device 6 updates a tap coefficient of the transversal filter 1 in a tap coefficient updating device 6. Simultaneously, a clock controller 7 gives a required minimum clock for the arithmetic operation of equalization.