Communication system and communication device

A communication system for transmitting a transmission signal in digital form from a transmitter to a receiver is disclosed. The transmitter includes a modulation part modulating a carrier wave in accordance with the transmission signal according to frequency modulation, a digital conversion part performing 1-bit quantization on the modulated signal obtained as a result of the modulation in the modulation part, and a transmission part transmitting digital data into which the modulated signal is converted in the digital conversion part. The receiver includes a reception part receiving the digital data transmitted from the transmission part, and a demodulation part demodulating the digital data received by the reception part according to the frequency modulation.