Everything in the house is analog signals, and LCD TV is digital TV. In the past, CRT TV was interlaced or progressive.
Interpretation of digital TV
( 1)& lt； Resolution >; Resolution, also known as resolution or sharpness, refers to the smallest number of particles or pixels in an image, which is reflected in a picture and refers to the number of pixels that the human eye can decompose. The resolution is generally expressed by luminance signal and M×N, where m is the number of pixels in the horizontal direction and n is the number of pixels in the vertical direction. For example, the resolution of HDTV is 1920× 1080 and that of SDTV is 720× 576. (2)& lt； Pixel >; Pixel is the smallest particle or unit for human eyes to understand an image. In professional technology, pixels represent the sampling points of image signals in the spatial domain. (3)& lt； Brightness signal >; A color signal consists of three primary colors: red, blue and green, but it can be decomposed into one brightness signal and two chroma signals (or color difference signals). (4)& lt； There are two kinds of TV signals: progressive scanning and interlaced scanning. Progressive scanning is also called sequential scanning, which means that the signals forming the image are arranged line by line in order. Interlaced scanning, also called interlaced scanning, refers to the formation of an image, which is first arranged in odd lines and then in even lines, thus forming two fields of signals; (5)& lt； Amplitude ratio >; Aspect ratio refers to the aspect ratio of a picture, 4:3 refers to the aspect ratio of 4:3, and 16:9 refers to the aspect ratio of 16:9. (6)& lt； 50/60/59.94 Hz & gtNTSC, PAL and SECAM all adopt interlaced scanning, so the scanning frequency of images is represented by field frequency, and 50/60/59.94HZ represents the field frequency of different systems respectively. (7) MPEG is the abbreviation of Moving Picture Experts Group, and has become an internationally famous digital TV image compression standard. MPEG belongs to ISO/IEC standardization organization. (8)& lt； 8VSB & gt8VSB is the channel coding and modulation method of digital TV broadcast adopted by American ATSC standard, which is called 8-level vestigial band modulation. (9) COFDM is a channel coding modulation method for digital TV broadcasting adopted by ETS-DVB-T in Europe, which is called coded orthogonal frequency division multiplexing modulation. ( 10)& lt； 5.lch surround sound >; 5. 1ch surround sound consists of five surround channels and a subwoofer channel. (1 1) QAM is a channel coding and modulation method adopted by DVB-C cable TV, which is called quadrature amplitude modulation.
Digital TV has been developing in China, China HDTV General Group, Radio Science Research Institute of SARFT, Tsinghua, Chengdian. 1September, 1998, the overall team completed the first domestic HDTV function prototype system, applied for 26 national invention patents successively, and was rated as the top ten scientific and technological progress in China by academicians of the two academies. 1999 10, the second generation HDTV system developed by the Corps successfully broadcast the National Day celebration. At the same time, there is another system for live broadcast, which was developed by the Institute of Broadcasting Science of the State Administration of Radio, Film and Television. After the National Day, we will continue to use ASTRI's system and broadcast two hours of programs for 50 users in Zhongnanhai every day. At present, all provinces and cities have started digital satellite DVB-S broadcasting. Terrestrial digital television broadcasting standards are being formulated; Digital cable broadcasting has been applied in some cities. It is predicted that in 2003, China HDTV standard will be issued, and in 2005, a quarter of TV stations in China will transmit and transmit digital TV signals. In 20 10, China plans to fully realize the digitalization of radio and television. 20 10, the relatively developed areas in the east popularize digital TV. 20 15 China will stop broadcasting analog radio and television. In the past, digital broadcasting was extended to the central and western regions of China. Faced with the aggressive momentum of foreign legions, the media generally believed that we could not bring hundreds of millions of color TVs to the market and be controlled by others, and we could not repeat the mistakes of VCD and DVD from the other side. At the moment when the global technical prospect is not very clear, China should make a breakthrough in the "digital TV industry".