Abstract: A waveform equalizer includes: a data signal input terminal for receiving an input data signal which is the object of waveform equalization; a plurality of S/H circuits each connected to the data signal input terminal; a sampling control circuit for repeatedly bringing the plurality of S/H circuits, one by one, to a sampling operation state; a selection circuit for selecting outputs of a predetermined number of S/H circuits which are in a hold operation state, respectively, from among the plurality of S/H circuits; a weighting circuit for weighting the outputs of the predetermined number of S/H circuits selected by the selection circuit; and an addition circuit for effecting an addition of outputs of the weighting circuit, thereby obtaining a waveform-equalized data signal from an output end of the addition circuit. By the constitution, it is possible to carry out a waveform equalization with high precision, and to realize a high speed of operation and a reduction in the scale of circuit.

Abstract: A composite semiconductor capacitor element, applicable to various kinds of circuits to reduce the influence of parasitic capacitance therein, includes two semiconductor capacitor elements connected in parallel by connecting terminals which have parasitic capacitances to terminals which do not have parasitic capacitances. Alternatively, two such semiconductor capacitor elements are connected in series by connecting terminals which have parasitic capacitances to each other. Hence, parasitic capacitances at the respective terminals are equal to each other. In addition, as compared with a conventional structure wherein a greater number of parasitic capacitances are connected to one terminal than to the other terminal, the parasitic capacitances are smaller at each terminal side.