Abstract: An infrared (IR) emission and reception circuit, which is composed of three parts, an IR transceiver circuit, a carrier-smoothed circuit, and a signal recognition circuit. The IR transceiver circuit receives an outside IR signal, converts it to an electrical signal, and then amplifies and shapes the electrical signal to form a carrier frequency read signal; the IR transceiver circuit also emits an IR signal outward. The carrier-smoothed circuit receives the carrier frequency read signal, filters out the carrier to form a carrier-smoothed signal, and outputs it to the signal recognition circuit. The signal recognition circuit receives the carrier-smoothed signal, and converts it to an IR recognition signal to output to the electronic-device processor. The electronic-device processor receives the carrier frequency read signal to recognize the carrier frequency of the outside IR signal, and also receives the IR recognition signal to learn IR control codes of the outside IR signal.