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Digital Video Transmitter & Receiver
What is NTSC?
NTSC, named for the National Television Standards Committee, is responsible for the development of the standard television broadcast transmission and reception protocol. In addition, there are two other standards, Phase Alternating Line (PAL) and Sequential Color and Memory (SECAM), which used for other countries in the world. NTSC has nothing changes except for adding new parameters of the color signal. While, NTSC signals cannot directly compatible with computer systems.
Each frame of the full-screen image has 525 horizontal lines. These lines are ranked from left to right and from top to bottom. Every line is jumping. Therefore, a complete frame screen of scanned in twice: first scan odd lines, another scan is even lines. Each half-frame screen scan takes about 1/60 seconds; entire frame scan is about 1/30 seconds. This interlaced scanning system also called interlacing. The NTSC signals can be converted into the digital signals that a computer could recognize by adapters. On the contrary, there is computer’s equipment can turn into an NTSC signals, which television receivers can be used by a computer monitor. However, due to the resolution of the universal television receiver than a normal display, even if the TV screen and then cannot meet all of the computer programs.
NTSC Television Standard
29.97 frames per second (reduced 30 frames), the TV scan lines are about 525 lines, even field in the front, and odd field in the rear, the standard resolution of NTEC TV is 720 x 480 pixels, 24-bit color bit depth, the picture the aspect ratio of 4:3 or 16:9. NTSC TV has been use in the United States, Japan and other countries and regions.
The difference between PAL AND NTSC
It is shown that the difference between color coding, decoding methods and field scanning frequencies. China (excluding Hong Kong and Taiwan), India, Pakistan and other countries used the PAL system. While, the United States, Japan, Taiwan, China, South Korea used NTSC.
The difference between PAL and NTSC, both of the film screenings are 24 film frames per second, however, the video images PAL format 50 fields per second, NTSC system is 60 fields per second. Because the TV is interlaced fields now, you can have general ideas of 30 full video frames per second in PAL, 25 full video frames per second in NSTC system.
Film only less one frame compared with PAL per second. Generally speaking, directly a frame to a frame for production in previous, so that the PAL per second to put one frame more than the film, is the speed of 1/24, and the tone of voice will rise. This is one of the reasons that DVD fans do not like the PAL system DVD. It is said that some of PAL DVD take 24 +1 production methods is one of the 24 frames repeat, which to get the same movie playback speed.
While, there are 30 frames per second in NTSC, it cannot be directly a frame to a frame for a production, so 24 film frames are converted into 30 video frames which could be used by 3-2 PULLDOW. These 30 video frames contained the same thing as 24 film frames. Thus, the NTSC playback speed is equal as film.
The same film for PAL system DVD is faster 1/24 than the NTSC system. Conversion time, the NTSC time X 23/24 = the PAL time.
The resolution ratio of PAL and NTSC
The resolution ratio of PAL is 720 x 576 and NTSC is 720 x 480, while PAL slightly dominant compared with the resolution ratio. PAL Select Display Resolution is 720 * 576, about 400 000 pixels. It is determined the PAL format digital camera CCD size should be in multiples of 400,000 or half multiples, such as 2 times or 1.5 times, so the PAL format digital video cameras are 800 000, or 107 million (nearly one million, 400,000 to 2.5 times), 1.55 million (nearly 1.6 million, 400,000-four times). NTSC Select Display Resolution of 720 x 480 is about 340 000 pixels, NTSC format digital video camera is usually 680 000 pixels and so on.