Remote control circuit a composed of RX5019 and RX5020

(1) Transmitting circuit
1) Circuit composition: This circuit consists of RPI, time base circuit LM555, RX5019 transmitting device, transmitting antenna and peripheral components.
2) Working principle: The transmitting circuit composed of RX5019 consists of time base circuit l. M555 constitutes a multivibrator. RP1 in the circuit is used to change
the oscillation frequency. Its frequency adjustment range is between 1 and 100 kHz, and its carrier frequency is 30 MHz. The oscillation signal enters the RX5019 from Q coupling, and
then is emitted outward by the antenna. The transmitting distance can reach 3-5km in an unobstructed environment and 1-3km in urban buildings. If a coaxial cable is used in a fixed location to connect to a telescopic antenna
installed at a high place , the signal transmission in the air can reach 8km. The signal input of RX5019- can be either a voice signal, various audio oscillation signals, music 1c signals or microphone signals, etc., as shown in the figure. ,     (2) Receiving circuit RX5-020 in the receiving circuit receives the signal from the transmitting circuit and is coupled to the input end of the audio decoder LM567 itself via the capacitor cI. When the natural frequency of LM567 itself is consistent with the transmitting frequency, its The 8th pin will output a low level, and the relay J will absorb the platform, so that the output signal of the RX5020 can be directly connected to the headphones, or it can also be connected to a load such as a speaker after a first-level amplification. The adjustment of the natural frequency of the load LM567 is completed by the potentiometer RP. . Its advantage is large emission range and long distance, but high voltage requirements, as shown in the figure.