Now the equipment that can be used for watching TV is no longer limited to the TV. As long as the problem of the use of multiple display devices is solved, the TV can be watched as with a projector.
If you want to use a projector to watch TV, the first prerequisite is that the projector you own must have a TV tuner. If your projector has a TV tuner, you only need to see if the projector has a radio frequency (RF) interface. With this interface, it has the function of receiving TV signals. (Radio frequency signal: In order to broadcast TV signals in the air, the entire video TV signal must be modulated into high-frequency or RF-Radio Frequency (RF-Radio Frequency) signals. Each signal occupies a channel so that multiple channels of TV programs can be broadcast simultaneously in the air. Will not cause confusion.
Our country samples the PAL system, each channel occupies 8MHz bandwidth; the United States adopts the NTSC system, TV from 2 to 69 channels, the bandwidth of each channel is 4MHz, the TV signal frequency band occupies a total of 54MHz to 806 MHz channels. CATV (Cable Television) works in a similar way, except that it transmits television signals through cables rather than through the air. After receiving the high-frequency signal of a certain channel, the TV must demodulate the entire TV signal from the high-frequency signal to reproduce the video image on the screen. ) Its main function is to demodulate the radio signal (or cable TV signal) transmitted by the local TV station into video and audio signals. Here, it should be noted that the format of the TV tuner of the projector you buy must conform to the local cable TV The format being transmitted.
The current projectors have basically achieved full compatibility in terms of video formats, but no full-standard compatible products have been seen in the radio frequency format. The projector that you have purchased with a different radio frequency format and the local TV system format will cause the consequences of not being able to watch normally. The phenomenon is that the color of the image is abnormal or the sound cannot be demodulated normally! But the projectors currently entering our country basically have no integrated radio frequency circuit, which is directly related to China’s tariff policy. The projectors without integrated TV tuner belong to IT industry production equipment, its tariff is very low, but the projector integrated with the TV tuner belongs to the home appliance product, and its tariff is very high! On the other hand, it is also related to the global sales strategy of the projector manufacturer , Projectors without integrated TV tuners are basically universal in the world, while the sales area of projectors with integrated TV tuners is fixed! Projector manufacturers canceled TV tuners, which not only reduces production costs, but also It has more advantages in the global distribution of goods.
The projector without RF input cannot directly watch TV signals. This is not to say that the projector cannot watch TV. It is common to expand the functions of the projector by using the supporting peripheral equipment. Use an external TV to tune. The projector demodulates the TV signal into S-VIDEO, VIDEO and AUDIO that the projector can recognize. The projector can receive the TV signal and enjoy the joyful visual impact that the big screen brings to you! Generally speaking, outside There are the following types of TV tuners:
The first category is professional TV tuners. These TV tuners have outstanding performance, stable and reliable work, and are usually used in professional locations. For example, a cable TV station converts the TV signal transmitted by a local wireless TV station and connects it to its own cable. TV network. But such products are expensive.
The second category is TV boxes. There are two main types of products in this category. One is TV boxes used on ordinary TVs. The main purpose of this product is to solve the problem that old TVs cannot receive supplementary channels transmitted by cable TV networks. The other The TV box is an external box designed to allow ordinary computer monitors to watch TV.
The third type of product is a video recorder product that became popular in the 1980s and 1990s, and the product has an integrated TV tuner. It can convert TV signals into VIDEO and AUDIO signals for output. However, since video recorders have faded out of the market, video recorder manufacturers have basically stopped the production of home video recorders in recent years. (An important indicator of whether the video recorder is used in home or professional situations is the home video recorder. All have TV tuners, and professional video recorders do not need to receive TV programs and do not integrate a TV tuner inside the video recorder. The previous video recorders have great defects for receiving current cable TV signals. Because the previous video recorders did not have supplementary frequency bands, they could not receive TV programs in supplementary frequency bands. At present, about 60% of the programs transmitted by cable television networks across the country are transmitted using supplementary frequency bands as carrier frequencies. The limitations of old video recorders are too great. Therefore, when using a projector to watch TV, I think it’s best to use a TV box that can be output to the computer. The current TV boxes basically have VIDEO and AUDIO output functions, which can be directly connected to the projector’s VIDEO and AUDIO. Input interface to connect. Even if the projector does not have VIDEO and AUDIO interfaces, you can also use the VGA output interface of the TV box and the VGA input interface of the projector to connect.
