Plastic Remote Control 52 keys for LG 43LH576T/ LG 43UQ8040PSB/ LG 55UQ7550PSF TV
The existing infrared remote control includes two modes: PWM (pulse width modulation) and ppm (pulse position modulation).
RC-5, rc-6 and future rc-7 of NEC and Philips are the representatives of the two forms of coding.
PWM (pulse width modulation): Represents "0" and "1" with the duty ratio of the infrared carrier wave. In order to save energy, in general, the time of transmitting the infrared carrier is fixed, and the duty cycle is changed by changing the time of not transmitting the carrier.
For example, the commonly used TV remote controller uses NEC upd6121, whose "0" is 0.56ms for carrier transmission and 0.56ms for non transmission; Its "1" is 0.56ms for carrier transmission and 1.68ms for non transmission; In addition, for the convenience of decoding, there is a pilot code. The pilot code of upd6121 is 9 ms for carrier transmission and 4.5 MS for no transmission. The total coding length of upd6121 is 108ms