1. What is? " frame ", In the first films , A still image is called a " frame (Frame)", The picture in the film is every second 24 frame , Why 24 frame , How does this number come from , Because the visual persistence of human eyes is exactly the same as per second 24 Frame standard , So it doesn't make sense to use more and waste film , Increase cost .
2. What is? " That's ok ", In our tradition CRT It's like TV , The scanning of an electron beam in the horizontal direction is called line , Or line scan .
3. What is? " site ", In our tradition CRT It's like TV , One line scan , Scanning in a vertical direction is called field , Or field scan .
4. What is? NTSC System ,NTSC(NationalTelevisionSystemCommittee) The system is 1952 Color television broadcasting standard established by the National Television Development Commission of the United States . U.S.A , Canada , as well as ***, Taiwan, China ,, the republic of korea , The Philippines and other countries adopt this system . The color bandwidth of this system is 3.58Mhz, The sound bandwidth is 6.0Mhz, Per second 30 Frame picture .
5. What is? PAL System ,PAL(PhaseAlternatingLine), yes 1965 Television system established in , Mainly used in China , Hong Kong , Middle East and Europe . The color bandwidth of this system is 4.43Mhz The sound bandwidth is 6.5Mhz, Per second 25 Frame picture , The other is SECAM System adopted in Germany , Because there are few applications , I won't give you more introductions .
6. Why NTSC Set to per second 30 frame , and PAL Standard per second 25 frame , This is because of the NTSC The city electricity of 110V60HZ, So the field frequency signal in the TV directly samples the frequency of the AC power supply 60HZ, Because two fields make up a frame , therefore 60 divide 2 be equal to 30 It's just the frame number of the TV , However, China's electricity market is 220V50HZ, So the reason is the same as above 25 It's a frame .
7. What is line by line , Each frame of television consists of several horizontal scanning lines ,PAL Make as 625 That's ok / frame ,NTSC Make as 525 That's ok / frame . If all the lines in this frame are continuous from top to bottom , Or the scanning order is 1,2,3……525, We call it progressive scanning .
8. What is interlace , actually , One frame of ordinary TV needs to be scanned twice , Scan only odd lines for the first time , That is l,3,5……525 That's ok , The second scan only scans even lines , That is 2,4,6……524 That's ok , This way of scanning is interlaced scanning . A picture with only odd or even lines is called a “ site (Field)”, The field with only odd rows is called odd field or front field (TopField), Fields with even rows are called even fields or Backfields (BottomField). That is to say, an odd field plus an even field equals one frame ( An image ).
9. What are the standards of digital TV , with *** Digital TV standard as an example , According to different display formats , Divided into the following 5 Specifications ：D1：480i format , and NTSC Analog TV has the same definition , The line frequency is 15.25kHzD2：480P format , And progressive scanning DVD Same specification , The line frequency is 31.5kHzD3：1080i format , The resolution is 1920×1080i/60Hz, The line frequency is 33.75kHzD4：720p format , The resolution is 1280×720p/60Hz, The line frequency is 45kHzD5：1080p format , The resolution is 1920×1080P/60Hz, The line frequency is 67.5KHZ among D1 and D2 Standard is the highest standard of our general analog TV , It can't be called high definition ,D3 Of 1080i Standard is the basic standard of HDTV , It's compatible 720p format , and D5 Of 1080P It's just a professional standard , It's not civil , As given above 60HZ It's just the ideal field frequency , And its line frequency is 67.5KHZ, At present, there is no such high line frequency TV , Actually in the professional field 1080P The field frequency of 24HZ,25HZ and 30HZ.