A system includes: a first modulator that modulates a first electric power at a first modulation frequency; a second modulator that modulates a second electric power at a second modulation frequency; a transmission line through which a transmission power obtained by combining a plurality of modulated electric powers is transmitted; a first demodulator that demodulates the transmission power at a first demodulation frequency to generate a third electric power; and a second demodulator that demodulates the transmission power at a second demodulation frequency to generate a fourth electric power. The first modulation frequency and the second modulation frequency are different from each other.