Motor steering infrared remote control circuit

Circuit working principle: Figure a shows the transmitter circuit. NAND gates 1 and 2 form
a 10 Hz ultra-low frequency oscillator, and NAND gates 3 and 4 form a 40 kHz carrier frequency oscillator.
VT, and VT2 constitute a high-gain amplifier. Press S. , SE303A emits
40 kHz infrared light modulated by 10 Hz ultra-low frequency. Press S:, SE303A emits 40 kHz infrared
light.
    Figure b shows the receiver circuit. Circuit principle IC． Used to
receive, amplify and demodulate infrared light signals . IC z (F, ~ F6) forms a pulse signal and DC signal discrimination
circuit. When pin 7 of Ic outputs a pulse signal, it can be identified by F, to F, causing
F3 to output a high level; when pin 7 of Ic outputs a low-level DC signal, it can be
identified by F4 to F6. Make F6 output high level. VT, VT2, VT6 and VT3, VT4,
, and W constitute the M forward and reverse drive circuit.