To obtain the device by which the number of components required to execute multiplication by an update unit in an adaptive equalization unit in a transceiver is reduced and to obtain its relating method.

An update unit of an adaptive, that is, an equalizer filter unit in a transceiver unit where information is coded at plural levels includes devices (51-56) that produce a product between an error signal and a data signal without the use of a multiplier unit. Plural levels, e.g. 5 signal levels are expressed by a logical signal format (b2, b1, b0). A control signal to process an error signal to provide a proper product by a component of the logical signal format (b2, b1, b0) is given. A sole arithmetic unit is an adder unit (56) that is required to couple a preceding coefficient Wn, t-1 with a product generated from the devices (51-56).