With the progress of science and technology, the digitalization of radio and television has become an inevitable development trend, and it is the general trend to cancel terrestrial analog TV signals.
The information about turning off TV this time is: Xuzhou: Jiangsu Satellite TV, CCTV 1; Seventeen sets of Fengxian comprehensive and central government; Suining county: Suining news synthesis; Pizhou City: Pizhou Comprehensive, etc. In Xuzhou, seven terrestrial analog TV signals are turned off at the same time. The original terrestrial analog TV viewers can continue to watch TV programs by opening cable TV, terrestrial digital TV and network TV.
When the signal is turned off, viewers can call 0516-85691614 for consultation.
Extended data:
Television receiving antenna function
1, receiving the high-frequency electromagnetic wave energy emitted by the TV station.
This is the main function of TV receiving antenna. Television stations modulate full-color TV signals and sound signals to be transmitted onto high-frequency carriers, which are radiated from antennas through TV transmitters and spread in all directions in free space.
After these electromagnetic waves reach the receiving antenna, they will excite induced electromotive force and induced current in the antenna conductor, and guide the electromagnetic waves to be transmitted from the antenna to the receiving system. In this way, the cable TV system gets a part of the energy of the radio wave emitted by the TV station, which enters the TV set after being processed and amplified, and is converted into the original video and audio signal. ?
2. Select the desired TV signal to suppress external interference.
There are many high-frequency electromagnetic waves transmitted in space. The electromagnetic waves emitted by different TV stations with different locations, program contents and carrier frequencies may induce induced currents on antenna conductors. However, due to the different receiving abilities of antennas to electromagnetic waves in different directions and frequencies, we can use this characteristic to receive TV signals in specific directions and channels by selecting TV antennas with different characteristics, and at the same time suppress the induced current generated by other TV signals on the conductor.
At the same time, it can suppress the interference from ionosphere, other radio waves, industrial interference and ghost interference caused by TV signal reflection.
3. Improve the ability to receive weak TV signals.
In areas far away from TV stations, especially in remote mountainous areas, the field strength of TV signals is very small. If the signal is amplified only by amplifiers, too many amplifiers are needed, which will inevitably lead to too much noise and unbearable nonlinear distortion. If you choose a high-gain TV receiving antenna (such as multi-unit receiving antenna, antenna array composed of multiple antennas, etc.). ), it can improve the level of TV signals entering the front end of the system, reduce the number of amplifiers needed, and greatly reduce noise and nonlinear distortion at the same time.