DATA TRANSMITTER

PROBLEM TO BE SOLVED: To provide a data transmitter that reduces a data error caused periodically in power line communication. SOLUTION: A detection circuit 14 of the transmitter 1 detects a timing when a power line voltage is 0 V, revises a modulation system of a modulation section 11 into a modulation system with high noise immunity for a prescribed time before and after the detected timing and the transmitter 1 transmits data. A receiver 2 uses a detection circuit 24 to detect a timing when the power lie voltage is 0 V, the receiver 2 revises a demodulation system of a demodulation section 21 into a demodulation system corresponding to the revised modulation system in the modulation section 11 for a prescribed time before and after the detected timing and the receiver outputs data.