What is Microwave Telecommunication?

- Mar 25, 2019-

What is Microwave Telecommunication?

 

Microwave Communication is a communication using electromagnetic waves with a wavelength between 0.1 mm and 1 m. Microwave communication does not require a solid medium, and microwave transmission can be used when the distance between two points is unobstructed.


What is Microwave Telecommunication


 The use of microwave for communication has large capacity, good quality and can be transmitted to a long distance. Therefore, it is an important communication means of the national communication network, and is also generally applicable to various dedicated communication networks. China's microwave communication widely uses L, S, C, and X frequency bands, and the application of K-band is still under development. Since the frequency of the microwave is extremely high and the wavelength is very short, its propagation characteristics in the air are similar to those of the light wave, that is, it is straight forward, and it is reflected or blocked when it encounters blocking. Therefore, the main mode of microwave communication is line-of-sight communication, exceeding Relaying is required after the line of sight. Generally speaking, due to the influence of the earth's secluded surface and the loss of space transmission, it is necessary to set up a relay station every 50 kilometers or so to extend and extend the electric wave. This type of communication, also known as microwave relay communication or microwave relay communication. Long-distance microwave communication trunks can be transmitted to thousands of kilometers after dozens of relays to maintain high communication quality. The equipment of the microwave station includes an antenna, a transceiver, a modulator, a multiplexing device, and a power supply device, an automatic control device, and the like. In order to gather the electric waves into a beam and send them to a distant place, a parabolic antenna is generally used, and the focusing effect can greatly increase the transmission distance. Multiple transceivers can use one antenna together without interference. In China, the current microwave system can work with six receivers and six transmitters in the same direction in the same frequency band, or eight transceivers can work simultaneously to increase the overall capacity of the microwave circuit. Multiplexed devices are available in analog and digital. Analog Microwave System Each transceiver can work on 60, 960, 1800 or 2700 channels and can be used for microwave circuits of different capacity levels. The digital microwave system uses digital multiplex equipment to form a group by 30-way telephone according to the principle of time division multiplexing, and then can form a secondary group of 120 channels, a third group of 480 channels, and a quadratic group of 1920 channels, and is modulated by a digital modulator on the transmitter. At the receiving end, the digital demodulator is restored to a multi-channel telephone. The latest microwave communication equipment, its digital series standard is exactly the same as the synchronous digital series (SDH) of optical fiber communication, called SDH microwave. This new microwave device can transmit more than 30,000 digital telephone circuits (2.4 Gbit/s) simultaneously on one circuit. Due to its wide frequency bandwidth and large capacity, microwave communication can be used for transmission of various telecommunication services, such as telephone, telegraph, data, fax and color TV, which can be transmitted through microwave circuits. Microwave communication has good disaster resistance. Microwave communication is generally unaffected by natural disasters such as floods, windstorms and earthquakes. However, microwaves are transmitted over the air and are susceptible to interference. The same frequency cannot be used in the same direction on the same microwave circuit. Therefore, the microwave circuit must be constructed under the strict management of the radio management department. In addition, due to the characteristics of the linear propagation of microwaves, there should be no high-rise blockage in the direction of the beam. Therefore, the urban planning department should consider the planning of the urban space microwave channel so that it is not affected by the barriers of high buildings and affect communication.