Views: Author: Changzhou Shengshijia Electronic Co., Ltd. Publish Time: 2022-08-25
On October 2, 1925 in the morning, the UK electrical engineer John luo ji baird, developed from his image in the receiver, clearly received a performance with the doll's face, which means that the TV was born. Baird developed a color TV set, again after successfully the image transferred to the other side of the Atlantic, a precursor for satellite television.
Turn on the TV, the screen showed wonderful TV program. This is a television station sends out. Television when sending television, must have the transmitter and the transmitting antenna, to carrying a radio waves of TV image and audio signal, send out in all directions, let television area around ten million TV sets to receive.
To increase the radio waves propagation distance, the expanded television reception area, in addition to enhance the output power of transmitter, and heightened the most economic and effective way is to send the antenna. Transmitting antenna erection, the higher the television station sends out the rectilinear propagation characteristics of uhf radio waves, the farther can spread, away from the television station area of the TV can receive TV programs. So, TV transmitting antenna, are set up in the towering spires of iron, or set up on the top of the mountain of top local or building platform.
The height of the TV transmitting antenna erection, however, will be affected by the limitation of objective conditions, can't continue to move up indefinitely. So scientists thought of hung over earth's equator, 35.77 million meters of artificial communications satellite. Use television antenna mounted on the satellite, its height is very most in the world. According to the calculation, from a 35770 km from ground satellite sent out on television, on the earth for about a third area can receive the TV. Therefore, as long as there are three such satellite, can achieve the global TV satellite. In this way, any other country in the world of news, through satellite television, immediately, can spread to the world, sitting at home, can also watch instantly to far thousands of kilometers outside of the Olympic Games.
Satellite, besides have a transmitting antenna and receiving antenna, amplifier, frequency converter and other electronic equipment. When television broadcast television program, first sent to the satellite. Satellite TV signal, after amplification, frequency conversion technology of processing, then on its transmitting antenna transmitted to the ground. Satellite into television in 35770 km altitude "sending antenna". The ten million TV set on the ground, as long as the installation of the dedicated satellite receiving antenna and the receiver, can see on the screen from sending off the satellite TV programs. In the platform of tall building, on the roof of the civil residence, place the disk of metal basin into the sky, is a special antenna for receiving satellite TV.