To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.

From Wikipedia, the free encyclopedia

PAL-S is the system of television receiver sets in the early days of the PAL system. Here PAL stands for Phase alternating at line rate and S stands for simple.

PAL system

The color hue modulates the phase of a subcarrier named color carrier. In PAL system the polarity of the phase in each frame is reversed to neutralize the undesirable phase shifts introduced during transmission. Thus the effect of undesirable phase shift is positive in one frame and negative in the second frame. Averaging the two, the effect of the undesirable phase shifts in two consecutive frames cancel each other.

The PAL-S receiver

In the early days of the PAL system, it was proposed that, the human eye can average the slightly different color hues in two consecutive frames and perceive the original color. The television receiver sets which rely on optical averaging were called PAL-S receivers.

The problems in PAL-S

However, it soon turned out that the optical averaging had problems. When the distance between the viewer and the receiver set is not large, the viewer can distinguish the lines. The phase reversion takes place in every frame. But each frame is composed of two fields. So the viewer watches two consecutive lines without reversion. The next two lines are reverted phase lines. That means that when there is undesired phase shift the viewer watches a thin horizontal bar with one color and another thin bar with another color. This pattern is known as Hanover bar.[1]

Electronic averaging

In the standard analogue PAL receiver, the color differences between the consecutive bars are averaged electronically (by the use of delay line). This system is known as PAL-D.

See also


  1. ^ Gordon J.King:Beginner’s Guide to Color Television, Newness Technical Book, London, 1978; ISBN 0-408-00101-1, p 69-71

This page was last edited on 15 September 2021, at 07:33
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.