Abstract: A load drive system for driving a load supplied with power from a power line includes a control unit which controls switching between the power line and the load and a communication unit which communicates using voltage and current of the power line. When performing the switching, the control unit controls, based on a width of a transition period of the power-line current, the transition period being attributable to the switching, timing of the switching so as to move the transition period away from a center of a period corresponding to a symbol communicated by the communication unit.

Abstract: A modulator includes an analog integrator including an analog circuit and a quantizer quantizing its output signal. An external input signal is input thereto. A modulator is coupled to the latter stage of the modulator, and includes a quantizer. A probe signal generation circuit injects a probe signal to the modulator. An adaptive filter searches for a transfer function of the modulator by observing an output signal of the quantizer in accordance with a probe signal. Another adaptive filter searches for a transfer function of the modulator by observing an output signal of the quantizer in accordance with the probe signal. A noise cancel circuit cancels a quantization error generated by the quantizer using search results of the adaptive filters.