Lifting antenna bracket microwave communication system

Communication system consisting of microwave transmitter, receiver, cable and antenna system, multiplexing equipment and user terminal equipment.

Microwave communication system, the use of microwave for communication has large capacity, good quality and can be transmitted to a long distance, so it is an important means of communication in the national communication network, and it is also widely applicable to all kinds of dedicated communication networks.

 

Using microwave for communication has large capacity, good quality and can be transmitted to a long distance. Therefore, it is an important means of communication in the national communication network and is generally applicable to all kinds of dedicated communication networks. Microwave communication is widely used in L, S, C and X frequency bands in China, and the application of K frequency band is still under development.

Because the frequency of microwave is extremely high and the wavelength is very short, the propagation characteristics in the air are similar to those of light wave, that is, straight forward, and it is reflected or blocked when it encounters blocking, therefore, the main way of microwave communication is line-of-sight communication, which needs relay forwarding after exceeding the line-of-sight.

Generally speaking, due to the influence of the Earth surface and the loss of space transmission, it is necessary to set up relay stations every 50 kilometers to amplify and forward the radio waves. This kind of communication mode, also known as microwave relay communication or microwave relay communication long-distance microwave communication trunk line can pass through dozens of relays to thousands of kilometers and still maintain high communication quality.

The equipment of microwave station includes antenna, transceiver, modulator, multiplexing equipment, power supply equipment, automatic controlling device, etc. In order to gather radio waves into beams and send them to distant places, parabolic antenna is generally used, and its focusing effect can greatly increase the transmission distance. Multiple transceiver can use one antenna together without interfering with each other. The current microwave system in our country can work at the same direction in the same frequency band with six receivers and six transmitters at the same time, it can also work at the same time to increase the overall capacity of the microwave circuit. Multiplexing equipment can be divided into analog and digital devices. Each transceiver of analog microwave system can work in 60 channels, 960 channels, 1800 channels or 2700 channels of communication, and can be used in microwave circuits of different capacity levels. The digital microwave system uses digital multiplexing equipment to form a primary group based on the principle of 30-way telephone on time division and multiplexing, and then can form 120 secondary groups, 480 tertiary groups, 1920 secondary groups, it is modulated on the transmitter by a digital modulator, and restored to a multi-channel telephone through a digital demodulator at the receiving end. The latest microwave communication equipment, whose digital series standard is completely consistent with the synchronous digital series (SDH) of optical fiber communication, is called SDH microwave. This new microwave equipment can transmit 30,000 multi-channel digital telephone circuits (2.4Gbit/s) simultaneously with eight beam waves in one circuit.

 

The source of the origin is a device that provides the original signal, and the signal output from the source is a digital signal after analog-to-digital conversion.

Channel coding is to improve the reliability of digital signal transmission. Because noise and interference inevitably exist in the Channel, the transmitted digital signal may generate error codes. In order to automatically check and correct incorrect symbols at the receiving end, channel encoder can add some additional symbols in the input digital series according to certain rules and form a new digital series. At the receiving end, check whether the received signal has error codes according to the regularity of the new digital symbol series.

Modulation is to modulate the digital signal to the carrier frequency with higher frequency so as to be suitable for wireless channel transmission. The functions of several blocks, such as the demodulator of the receiver and the decoding of the channel, and the blocks of the initiator are one-to-one inverse conversion.