PURPOSE: To attain the nonlinear processing with a characteristic different from one and the same device by taking a difference between an output level and a limit level of the coefficient section and using a sign bit so as to switch the output signal and the limit level signal of the coefficient section.

CONSTITUTION: An output section 30 receives an output of the coefficient section 20 to take a difference between the output level and the limit level. The code bit depending on the quantity is utilized and when the output signal is lower than the limit level, the signal is outputted as it is and when the output signal is over the limit level, the signal is outputted as a limit level signal to provide the limiter characteristic. The coring characteristic given to the coefficient section 20 depends on the coring level given externally and the limiter characteristic is varied optionally by the limit level given externally. Moreover, the coefficient section 20 uses plural bit shift circuits 21A∼21D to multiply a prescribed coefficient with the input signal, the resulting signals are combined by the external data and the result is synthesized to obtain optional coefficients with a step.