Pal

Palé is a town and sub-prefecture in the Nzérékoré Prefecture in the Nzérékoré Region of Guinea.

PAL (an acronym for Phase Alternating Line) is a colour encoding system for analogue television. It was one of the three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 frames) per second, and associated with CCIR analogue broadcast television systems B, D, G, H, I and K. The articles on analogue broadcast television systems further describe frame rates, image resolution, and audio modulation. PAL was developed by Walter Bruch at Telefunken in Hanover, West Germany, with important input from . The format was patented by Telefunken in December 1962, citing Bruch as inventor, and unveiled to members of the European Broadcasting Union (EBU) on 3 January 1963. When asked why the system was named "PAL" and not "Bruch", the inventor answered that a "Bruch system" would probably not have sold very well ("Bruch" is the German word for "breakage" ). The 4.43361875 MHz frequency of the colour carrier is a result of 283.75 colour clock cycles per line plus a 25 Hz offset to avoid interferences. Since the line frequency (number of lines per second) is 15625 Hz (625 lines × 50 Hz ÷ 2), the colour carrier frequency calculates as follows: 4.43361875 MHz = 283.75 × 15625 Hz + 25 Hz. The frequency 50 Hz is the optional refresh frequency of the monitor to be able to create an illusion of motion, while 625 lines means the vertical lines or resolution that the PAL system supports. The original colour carrier is required by the colour decoder to recreate the colour difference signals. Since the carrier is not transmitted with the video information it has to be generated locally in the receiver. In order that the phase of this locally generated signal can match the transmitted information, a 10-cycle burst of colour subcarrier is added to the video signal shortly after the line sync pulse, but before the picture information, during the so-called back porch. This colour burst is not actually in phase with the original colour subcarrier, but leads it by 45 degrees on the odd lines and lags it by 45 degrees on the even lines. This swinging burst enables the colour decoder circuitry to distinguish the phase of the R-Y' vector which reverses every line. E'{\scriptstyle\text{Y}}= 0.299E'{\scriptstyle\text{R}} + 0.587E'{\scriptstyle\text{G}} + 0.114E'{\scriptstyle\text{B}} E'{\scriptstyle\text{U}} and E'{\scriptstyle\text{V}} are used to transmit chrominance. Each has a typical bandwidth of 1.3 MHz. E'{\scriptstyle\text{U}} = 0.492(E'{\scriptstyle\text{B}}-E'{\scriptstyle\text{Y}}) E'{\scriptstyle\text{V}} = 0.877(E'{\scriptstyle\text{R}}-E'{\scriptstyle\text{Y}}) Composite PAL signal = E'{\scriptstyle\text{Y}} + E'{\scriptstyle\text{U}} \sin (\omega t) + E'{\scriptstyle\text{V}} \cos (\omega t) + timing where \omega = 2\pi F_{SC} . Subcarrier frequency F_{SC} is 4.43361875 MHz (±5 Hz) for PAL-B/D/G/H/I/N. == Countries and territories using PAL, past and present == A legacy list of PAL users in 1998 is available on Recommendation ITU-R BT.470-6 - Conventional Television Systems, Appendix 1 to Annex 1. === Countries and territories no longer using PAL ===

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