The infrared receiving tube is a device that directly converts electrical energy into near-infrared light and belongs to the diode category. Its structure and principle are similar to those of general light-emitting diodes, except that the semiconductor materials are different. The infrared receiving head is a receiving, amplifying, and demodulating device. The internal integrated circuit has completed the demodulation and the output is a digital signal. The infrared receiving head consists of two parts: IC and PD. IC is the processing element of the receiving head, mainly composed of silicon crystals and circuits. It is a highly integrated device. PD is a photodiode, and its main function is to receive light signals. Infrared reception needs to be demodulated first, and the demodulation process is received through the infrared receiving tube. Its basic working process is: when the infrared receiving module receives the modulated signal, it outputs a high level, otherwise it outputs a low level, which is the reverse process of modulation. The original data signal output by the infrared receiving head is exactly the opposite of the transmitting end. That is, if the original signal of the transmitting end was at a high level before, then the output of the receiving head is a low level. On the contrary, the signal sent by the infrared remote control is a series of binary pulse codes. In order to prevent it from being interfered with by other infrared signals during wireless transmission, it is usually modulated on a specific carrier frequency - 38kHZ and then transmitted through an infrared emitting diode. The infrared sensor integrates receiving and modulating infrared rays. The infrared receiving device must filter out other clutter, receive the signal of the specific frequency and restore it to a binary pulse code, which is demodulation.
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