Ground wave digital Television Broadcasting
It is digital broadcasting begun by using UHF belt of the ground wave in the sphere of three large areas in December, 2003. At this time, a past, analog Television Broadcasting electric wave was left, and it became operation of a digital electric wave and both parties.
In the terrestrial digital broadcasting, a usual broadcasting a digital high-resolution and high sound quality can be done with the high-resolution and the high sound quality program of the digital Hi-Vision. Moreover, a useful latest information program for the interactive program, the senior citizen, and the handicapped person easily the welfare program and to live etc. are being offered.
Necessity for digital broadcasting
The spread of cellular phones etc. make the frequency of the electric wave insufficient around the mobile telecommunications field. Moreover, new service of the wireless Internet etc. appears one after another, and it has become a situation not to be able to answer the demand for a new electric wave.
When the analog broadcasting is digitalized, a lot of information can be sent by the same bandwidth. When the ground wave analog broadcasting is completely digitalized, about 1/3 of the present Television Broadcasting frequencies can be finally used for a new usage. In a word, the purpose is to use the frequency of the electric wave effectively.
Use frequency of terrestrial digital broadcasting
The use frequency of the terrestrial digital broadcasting is UHF belt. UHF says, "Ultra high frequency", and is a frequency band from 300MHz to 3GHz. Television Broadcasting is using everything from 470MHz to 770MHz in that, and the number from 13 channels to 62 channels is attached. The antenna for UHF is necessary for the reception of UHF.
The electric wave of the VHF belt used for ground wave analog Television Broadcasting is not used in the terrestrial digital broadcasting. As for the antenna of VHF, the frequencies were lower than UHF, and the antenna was more large-scale.
Advantageous point for digital broadcasting
Digital broadcasting becomes the high-resolution and high sound quality
The voice broadcasting of a high-definition television broadcasting and average CD in a past, analog terrestrial broadcasting without becomes possible. Moreover, it becomes difficult to receive the influence of the noise by digitalizing it. Such "Ghost" disappears though the image of the television became a double reflection in the analog broadcasting.
The multi of the program can be organized.
A lot of information can be sent at a time in case of digital broadcasting by the same width of the channel. Broadcasting a standard image quality it, it becomes possible to broadcast the program of three channels or less at the same time with one channel. The multi of the program can be organized with this.
The data broadcasting can be used.
Because the data broadcasting can be combined with the program, the broadcast captioning and the explanation broadcasting service can be done at the same time.
The electronic program guide can be used.
The electronic program guide is a function to display the program before one week from the day on the television screen like the television schedule in the newspaper. The watching reservation and the recording reservation can be easily done with the program schedule. The program of the confirmation of the content of the program and the genre that I want to see can be retrieved.
The one-segment broadcasting is possible.
Because the one-segment broadcasting can do a steady reception by using a digital characteristic while even moving, the broadcasting service for the movable body such as the car, trains, and buses and the broadcasting service for the cellular phone and the portable terminal are possible.
Drawback of digital broadcasting
Digital telecast is not only good. It might be bad. Even if analog Television Broadcasting can see barely when strength of the electric wave weakens, it is likely not to see it in digital broadcasting at all.
Moreover, the price gradually becomes cheap generally by development and the effect of mass production of special IC as for a digital television though there is a fault that the circuit becomes complex and the price is high.