RF wireless module is a module that uses wireless technology for wireless transmission. The wireless module is mainly composed of transmitter, receiver and controller.
Wireless communication modules are widely used in vehicle monitoring, remote control, telemetry, small wireless networks, wireless meter reading, access control systems, cell paging, industrial data acquisition systems, wireless tags, identification, non-contact RF smart cards, small wireless data terminals, security Fire protection system, wireless remote control system, biological signal acquisition, hydrometeorological monitoring, robot control, wireless 232 data communication, wireless 485/422 data communication, digital audio, digital image transmission and other fields.
The main technical indicators of the wireless module:
Modulation Mode : ASK Working frequency: 315MHZ/433.92MHZ Frequency stability: ±75KHZ Transmitting power: ≤500MW Quiescent current: ≤0.1UA Emission current: 3～50MA Working voltage: DC 3～12V
The function of the wireless module:
Communication function, support GPRS and short message dual-channel data transmission; support multi-center data communication. Adopt function to collect serial device data, such as serial instrument, collector, PLC, etc. Remote management function, support remote parameter setting and program upgrade.
Transmission mode of wireless module
It is one of the solutions to solve the monitoring and transmission of difficult wiring places of several kilometers or even tens of kilometers. Using the method of frequency modulation modulation or amplitude modulation modulation, the image is mounted on a high-frequency carrier, converted into high-frequency electromagnetic waves, and transmitted in the air. Its advantages are: low comprehensive cost, more stable performance, eliminating the need for wiring and cable maintenance costs; dynamic real-time transmission of broadcast-level images, good image transmission clarity, and complete real-time; flexible networking, good scalability, plug-in Ready to use; low maintenance. The disadvantage is: due to the use of microwave transmission, the frequency band is above 1GHz, and the commonly used L-band (1.0-2.0GHz), S-band (2.0-3.0GHz), Ku-band (10-12GHz), the transmission environment is an open space, If it is used in a big city, the radio waves are more complicated and are relatively susceptible to external electromagnetic interference; the microwave signal is transmitted in a straight line, and there should be no mountains or buildings in the middle; More serious, especially in rainy and snowy weather, there will be more serious rain attenuation. However, there are also digital microwave video transmission products, which have improved anti-interference ability and scalability.
Twisted pair transmission
It is also a kind of video baseband transmission, which converts the 75Ω unbalanced mode into a balanced mode for transmission. It is a good solution to solve the problem of monitoring image transmission within 1Km, the electromagnetic environment is relatively complex, and the situation is better, and the monitoring image signal processing is transmitted in a balanced and symmetrical manner. Its advantages are: simple wiring, low cost, strong anti-common mode dry worry performance.