Abstract: A signal processing circuit is configured by connecting a plurality of basic circuits connected in series, each of the basic circuits comprising an arithmetic circuit subjecting a first input signal and a second input signal to a signal processing; a first selection circuit outputting the first input signal or an output signal of the arithmetic circuit; and a second selection circuit outputting the second input signal or an output signal of the arithmetic circuit, so as to make it possible to change operations of the circuit as a whole by properly making a selection on which signal should be output with the aid of the first and second selection circuits, and to execute different signal processing on a single circuit depending on the selection.

Abstract: A semi-fixed circuit has a plurality of flip flops connectable in series, a first selector and a second selector, and is capable of operations of a plurality of kinds of scrambler and the like. The first selector selects any one of an exclusive OR signal of an input signal and a first feedback signal, the first feedback signal and the input signal, and outputting the result to a first flip flop. The second selector is capable of selecting an exclusive OR signal of an output signal of a second flip flop and a second feedback signal, an output signal of the second flip flop and the second feedback signal, and outputting the result to the first selector as the first feedback signal.