Differences

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--- digital_television [2020/11/06 21:34] – hkimscil
+++ digital_television [2024/12/05 08:55] (current) – hkimscil
@@ Line 1: / Line 1: @@
 ====== Analog Television ======
-^ ^ NTSC  ^ PAL  ^
+^ ^ [[:NTSC]]((see http://www.ktword.co.kr/test/view/view.php?no=999))  ^ [[:PAL]]  ^
 | stands for   | National Television System Committee  | Phase Alternation by Line  |
 | Bandwidth  | 6 MHz  | 7 to 8 MHz  |
 | Vertical Freq  | 60 Hz  | 50 Hz  |
 | Horizontal Frequency  | 15.734 kHz  | 15.625 kHz  |
-| Lines/Field  | 525  | 625  |
+| Lines  | 525 (480)  | 625 (576)  |
-| Field per sec. | 60  | 50  |
+| Fields per sec. | 60  | 50  |
-| Frame per sec. | 30  | 25  |
+| Frame((Analog TVs use a cathode-ray tube (CRT) to beam light against the backside of a screen. These tubes aren’t like projectors—they can’t fill up a screen in one go. Instead, they quickly beam light down from the top of a screen. As a result, though, the picture at the top of the screen starts to fade as the CRT beams light at the bottom of the screen. from https://www.howtogeek.com/428987/whats-the-difference-between-ntsc-and-pal/)) per sec. | 30  | 25  |
 {{https://static.diffen.com/uploadz/thumb/f/ff/PAL-NTSC.svg/610px-PAL-NTSC.svg.png}}
+see also https://www.diffen.com/difference/NTSC_vs_PAL
 ====== Dital Broadcasting -- IPTV and all others ======
 reference. {{:databroadcastetri.pdf|ETRI 보고서}} PDF
-Analog to Digital
-| A  |  D  | 비고  |
-| terrestrial broadcast (TB)  | digital TB   | free . . . \\  cf. [[wp>Aereo|Aereo antenna]]   |
-| CA  | @lightgreen: Digital CA  | 통신사 + 케이블 회사 \\ mobile + internet + tv + \\ music + tv/movie content service \\  \\ PP (TB 포함)와 함께 subscribers 확보  |
-| <del>satellite</del>  | @lightgreen: Satellite television  | :::  |
-|   | @lightgreen: IPTV  | :::  |
-즉, 어떤 contents를 어떻게 전달할 것인가가 앞으로의 과제.
-  * customization
-  * connected TV
-[[wp>Aereo|Aereo antenna]] . . .
 Conversion of analogue television signals to digital signals -> __sampling__
@@ Line 38: / Line 26: @@
     * robust signals
     * uses **less bandwidth**
-  * sending information
+그러나 영상 외에도 필요해지는 것
+  * sending (and receiving) information
     * via one channel: one-way channel, broadcast channel, forward path, or in-band channel, etc.
     * via two channel: two-way channel, interactional channel, **return path**, back channel or out-of-band channel, etc.
@@ Line 93: / Line 82: @@
   * GEM (Globally Executable MHP)
     * MHP에서 유럽 방송환경에만 쓰이는 요소를 제거하여 OCAP과 ACAP에 이용하기 용이하도록 한 표준임.
-  * OCAP (OpenCableApplication Platform)
+  * OCAP (Open Cable Application Platform)
-    * 미국 케이블 방송 기구인 Cable Labs에서 제정한 양방향 TV 미들웨어 표준
+    * 미국 케이블 방송 기구인 SCTE(Society of Cable Television Engineers) 에서 지원
+    * Cable Labs에서 제정한 양방향 TV 미들웨어 표준
     * GEM에 Open Cable의 환경적인 요소를 추가하는 식으로 제정
   * ACAP (Advanced Common Application Platform)
@@ Line 107: / Line 97: @@
     * 거래형 양방향 TV 서비스를 위해서 복잡한 매체별 사업 관계
 ----
-  * [[:DVB]]
+  * [[:DVB]] see http://dvb.org
   * [[:MHP]]
   * [[:ATSC]]: Advanced Television Systems Committee