模拟视频信号知识
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High Speed Amplifiers for Video Applications
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Video Groups & Specifications
NTSC :National Television System Committee. The US form of standard definition TV.
PAL :Phase Alternating Line. The system of standard definition TV implemented in Europe & elsewhere.SECAM :Sequential Couleur avec Memoire. The French form of standard definition TV.
ATSC:Advanced Television Systems Committee. The US form of high definition TV (HDTV).
VESA:Video Electronics Standards Association. Proposes, publishes video standards for Graphics. ITU:International Telecommunications Union. Proposes, publishes video standards for broadcast in EU.SMPTE:Society of Motion Picture & TV Engineers. Proposes, publishes standards for broadcast in US.MPEG:Motion Picture Experts Group. Proposes and publishes video standards for Broadcast. EIA 770.1:The US spec for Enhanced Component video, similar to ITU-R BT1197/ETSI 300 294.EIA 770.2:The US spec for Standard Definition TV (SDTV) Baseband Component Video. EIA 770.3:The US spec for High Definition TV (HDTV) Baseband Video.
ITU-R BT.470:Harmonized spec for SDTV world wide, including NTSC, PAL, and SECAM.
ITU-R BT.601:Universal Sampling spec for SDTV and HDTV Broadcast Video. Similar to SMPTE125M.
ITU-R BT1197/ETSI 300 294:Spec for PAL Plus Enhanced TV in Europe.
SMPTE 125M:Similar to ITU-R BT.601.
SMPTE 170M :Has replaced EIA RS 170A, color spec for NTSC.
SMPTE 253M :RGB Analog Video Interface spec for SDTV Studio applications. SMPTE 274M :Spec for 1920x1080 HDTV.
SMPTE 296M :Spec for 1280 x 720 RGB and YPbPr Baseband Video. Similar to PAL Plus.
Analog TV Standards
SD/HD TV standards -US SD/HD TV standards –WW
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NTSC/480i (Interlaced)
–720 (H) x 480(V) active video resolution (720 x 240 active / field)
–858 x 525total resolution
–V refresh rate (frame rate) : 29.97 Hz (59.94 Hz field rate)–H scan line rate : 15.734 kHz
PAL/576i (Interlaced)
–720 x 576active video resolution (720 x 288 active / field)–864 x 625total resolution
–V refresh rate (frame rate) : 25 Hz (50 Hz field rate)–H scan line rate : 15.625 kHz
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a lot of variations (PAL I, B, G, H, D, N, M)
人们常常按照每帧的有效垂直分辨度和扫描类型来表述视频信号的格式，这里I表示隔行（interlaced）扫描、P 表示逐行（progressive）扫描。
在隔行扫描格式中，一帧视频画面分两场来扫描。
以PAL 制式为例，则首先扫描包含#1-312.5行的奇数场。然后再扫描包含#312.5-625行的偶数场。
奇数、偶数场都以50场/秒的速率扫描，这等于25帧/秒。480i 格式具有总共525行的垂直分辨度（包括有效行和消隐行）。576i 格式具有总共625行的垂直分辨度。
480p (Progressive)
–720 x 480active video resolution
–858 x 525total resolution
–V refresh rate: 59.94 Hz
–H scan line rate: 31.469 kHz
576p (Progressive)
–720 x 576active video resolution
–864 x 625total resolution
–V refresh rate: 50 Hz
–H scan line rate: 31.25 kHz
4在逐行扫描格式中，所有的扫描线都在一帧或者一场中扫描，这样就生成了分辨度更高的画面，并降低了扫描线的可见性和画面的闪烁。