MCD Red Apple is IR wireless transmission module suitable for indoor use. It consists of carrier, and audio compressing and expanding circuit. Instead of general LC oscillation, PLL is used in Red Apple carrier circuit, with frequency range 2.8~4.5MHz. The receiver consists of IR demodulation receiving and audio demodulation, audio compressing and squelch circuits, pilot muting, MCU control and other functions. By simply adding external power, an audio socket, it can be embedded in a variety of devices, such as audio amplifier. The transmitter consists of IR transmitting, audio compressing, pilot frequency, MCU control and other circuits. By simply adding an external MIC and a shell, it can be made into an IR wireless voice transmitter, such as hand held or belt-pack device.

Among more and more wireless electromagnetic radiation electrical consumer products, IR wireless transmission is unique green electrical product. They could be sold to any country without frequency application or CE and FCC certification. MCD Red Apple comes with the common feature of IR transmission--confidentiality. Different from UHF signal which can go through walls, IR signal rebounds back when it is blocked by walls. It does not interfere with IR transmission of wireless MIC in the next room. In addition, PLL is adopted, with stable frequency, wide frequency response (50HZ-15KHz) and low signal distortion (