NTSC, PAL, CVBS

TV system별 클럭차이..

결론(?)은 서브캐리어의 차이인데.. CVBS는 음성 없이 영상만 NTSC/PAL을 실어나르는데..

왜 27MHz로 30fps로 동일하지 -ㅁ-?

28.6363MHz for NTSC or 28.375MHz for PAL

CVBS (30 fps @ 27Mhz)

27MHz crystal clock for subcarrier generation

[링크 : http://datasheet.octopart.com/TW9920-BC1-GR-Intersil-datasheet-14388706.pdf]

In PAL system, the frequency of the system clock and the subcarrier signal are 28.375 MHz and 4.4336 MHz

[링크 : http://www.google.com/patents/US5946053]

In the PAL system, the color subcarrier is 4.43 MHz above the video carrier, while in the NTSC system it is 3.58 MHz above the video carrier. 

[링크 : https://en.wikipedia.org/wiki/Chrominance]

The frequency of this subcarrier is 4.43361875 MHz for PAL, compared to 3.579545 MHz for NTSC. The SECAM system, on the other hand, uses a frequency modulation scheme on its two line alternate colour subcarriers 4.25000 and 4.40625 MHz.

[링크 : https://en.wikipedia.org/wiki/PAL]

[링크 : http://wodnrrns.tistory.com/entry/NTSC-PAL-비교]