Patent ID: 7974412

Claim:
A communication system, comprising: a transmission device that transmits an information signal having information defined as a binary state value, the transmission device including a signal generation unit that generates an information decryption signal to transmit the information decryption signal together with the information signal, wherein the state value of the information decryption signal is unchanged when the state value of the information signal is changed, whereas the state value of the information decryption signal is changed when the state value of the information signal is unchanged; and a reception device that receives the information signal and the information decryption signal, the reception device including an information acquisition unit that acquires the state value of the information signal based on a changing timing of the state value of each of the information signal and the information decryption signal received, wherein the information acquisition unit includes: a first pulse generation circuit that generates a first pulse signal in sync with the change of the state value of the information signal; a second pulse generation circuit that generates a second pulse signal in sync with the change of the state value of the information decryption signal; a OR circuit that outputs a OR signal of the first and the second pulse signals, a first delay circuit that delays the OR signal by a predetermined time; a coincidence detection circuit that counts a value in sync with the OR signal delayed by the first delay circuit to output a coincidence detection signal when the counted value is coincident with the number of bits of a single information element contained in the information signal; a serial-to-parallel conversion circuit that receives the information signal and the OR signal delayed by the first delay circuit to perform a serial-to-parallel conversion of the information signal in sync with the OR signal; and a signal processing circuit that acquires the serial-to-parallel converted information signal in sync with the coincidence detection signal.