Maybe you have not paid attention to the development and changes in the field of flat-panel TVs and HDTVs in time, but they have been developing rapidly. Through the above review of time events, you can see the development of digital terrestrial TV in China, but Maybe you don't know about digital HDTV on the ground now. If you are planning to buy a flat-panel TV, you must have a systematic understanding of the current digital HDTV. Otherwise, it will probably be fooled by the promoters' rhetoric. .
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For example, in order to sell some outdated models, the promoters said to some consumers who don’t know the market: “HD is far away, and now it’s not necessary to buy HDTV,†so the difference between digital TV and analog TV. It is necessary to start to understand terrestrial digital broadcast television.
The difference between digital TV and analog TV
To understand in depth what is China's terrestrial digital TV, you need to know what the difference between analog TV and digital TV is. Simply put, analog TV programs are generated, transmitted, and processed from analog TV program image signals.
Almost all of the processes are done under the simulation system. The reception and recovery of the analog TV is almost entirely done under the simulation system.
Audio, video and data signals for digital television programs are used from source coding, channel coding and modulation
Digital technology, and digital televisions also use digital technology to receive and process such programs.
Is digital TV transmitted in several ways?
Simply put, digital TV can be accessed through satellite, terrestrial broadcasting, cable TV systems, and broadband. The author will introduce these transmission methods one by one.
·Satellite transmission
Satellite TV is not new to some enthusiasts, but it is more mysterious to the general public. In fact, the use of satellite TV is very simple, only need a receiver box and an antenna (commonly known as "pot"), and then adjust the search parameters, you can watch it normally. The adjustment method needs to refer to some corresponding instructions.
Satellite receiver
Using satellites is a good choice, but it is subject to restrictions. For example, different satellite coverage areas are limited. It is not a place where friends or friends in any direction can use it normally. It is illegal for Chinese individuals to use satellite TV, so it is not popular.
· terrestrial broadcast transmission
Digital terrestrial broadcasting is more commonly used in China as a terrestrial broadcast transmission standard. Similar to the early years of wireless television, it is simply said that the TV tower's TV tower transmits signals and then covers a certain city range. For example, mobile TVs used in many areas are received through this transmission standard.
The national standard enforced this standard and gradually upgraded it and upgraded it. It has become a standard for terrestrial digital broadcasting announced by the Ministry of Information Industry of China - DMB-T/H, which is the promotion of DMB-T and Shanghai Jiaotong University. ADTB-T fusion program.
·Wired and broadband
Cable digital TV is one of the most convenient and cheapest ways to implement digital TV transmission. It can be viewed by using the old cable TV transmission network. It only needs to be equipped with a receiver set-top box at the receiving end to save it. The user has trouble erecting the antenna by himself.
Since the digital signal is transmitted and reproduced at the terminal, the quality of the signal received by the cable digital television is the same as that of the transmitting front end, and the occurrence of twill, snow, and the like is avoided, and the SD digital signal can achieve a DVD-like image quality. High-definition digital signals can achieve up to 6 times the definition of SD.
Wired and IPTV are easier for users who often watch TV and Internet, and the manufacturers are mainly telecom departments rather than broadcasting. From the characteristics of TV broadcasting, the current XDSL is not suitable for point-to-multipoint transmission, and maybe wait until later. Fiber-to-the-home and triple play are more potential when they become a reality.
Transmission mode is more and the ground digital transmission DMB-TH becomes Chinese standard
In Chinese cities, satellites are banned, analog signals are eliminated, and IPTV cannot achieve satisfactory results. Therefore, digital terrestrial broadcast transmission has become the only standard, and the country will force all DMB-TH handovers nationwide on August 1 this year. ,
What is the ground?
According to the definition of “Digital Television Receiving Equipment Terminology†by the Ministry of Information Industry SJ/T11324-2006, terrestrial digital television refers to “a television system that transmits digital television signals by means of terrestrial broadcasting.â€
The "ground" mentioned here is not the same as our general understanding. "Ground digital TV" has nothing to do with this "ground" under our feet.
The TV signal of "Ground Digital TV" is broadcasted to the air through the TV tower, and then received by the user as an antenna.
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