Infrared nine-function remote control circuit b

Shown is an infrared remote control transmitter circuit composed of TM703. For the transmitting circuit TM703, the internal
oscillator generates the main pulse of the circuit, the clock circuit generates the timing pulse, and the judgment circuit interprets the input control signal and sends it to the coded circuit. The control code is generated after coding in time sequence
. The output buffer circuit gives sufficient amplification to the output control signal and LED display signal to improve its output load
capacity. When any button of the transmitting circuit is pressed, it is output from pin 14 (O/P) after being internally encoded by TM703. After being amplified by the transistor,
it is sent to the infrared emission tube for emission.
    Figure 18-58b corresponds to the infrared remote control receiving circuit. The oscillator, clock circuit and output buffer of the receiving circuit TM702 have the
same functions as the TM703, but its control circuit is used to control the opening and closing of the encoder. When the external modulated remote control signal is sent to the decoder from the "I/P", the decoder
decodes according to the time sequence controlled by the clock. The output control code is amplified by the buffer amplifier and then sends control instructions to the object. After the receiving circuit
receives this signal , it is amplified by the infrared demodulator, demodulated, and then sent to the ⑥ pin (I/P) of TM702. After internal decoding,
the control end of the corresponding function is controlled from high level to low. level, the corresponding actuator starts to work. When debugging the circuit, the potential RP
(500kHz) should be adjusted separately to make the transmitting/receiving circuit operating frequency the same, and the circuit can work normally.