Where is pal and ntsc

The result for an NTSC television is 30 frames of a complete image, made up of two fields for each frame, appearing every second. Since countries in Europe and Asia often use a 50 hertz power supply , the equivalent PAL lines go out at 50 fields per second. This means that a PAL signal displays at 25 fps, consisting of two sets of 25 alternating lines. More lines usually means more visual information, which results in better picture quality and resolution.

When an NTSC videotape is converted to PAL, black bars are often used to compensate for the smaller screen aspect, much like the bars at the top and bottom of a letterbox or "widescreen" movie. When the NTSC format was first adopted in , there was little discussion of color transmissions. It's similar to PAL, but processes color differently. Early TV displays were CRT cathode ray tube , which flash lights very quickly to produce images on the screen.

A low refresh rate the speed at which on-screen images update would result in flickering on these displays. This flicker is distracting and can even make you feel sick, so obviously it's not ideal. Since bandwidth was very limited at the time, it wasn't feasible to transmit TV signals at a high enough refresh rate to avoid flicker, while also keeping the picture at a high enough resolution to be watchable.

As a workaround, TV signals used a technique called interlacing to effectively double the frame rate without using additional bandwidth. Interlacing is the act of splitting video into two separate "fields" and displaying them one right after the other. All of the even-numbered lines of video show in one field, while the odd-numbered lines are in a second field. The video switches between the odd and even lines so fast that the human eye doesn't notice, and can fully enjoy the video.

Interlaced scan contrasts with progressive scan, where every line of a video is drawn in a normal sequence. This results in higher-quality video and is often used today , but wasn't feasible in the past due to bandwidth limitations.

Now that you're familiar with the process of interlacing, let's move on to see how the NTSC and PAL standards handle this process differently. We've explained frame rates and refresh rates before, which you should review if you're not familiar. The pictures need to come at a rate of 20 pictures per second to create this illusion. Each of these "rapidly changing" pictures is a frame. A typical TV transmission is at frames per second fps. Each frame consists of several closely spaced lines.

The lines are scanned from left to right and from top to left. A typical TV picture consists of to lines. Considering this large number of lines, if all were to be written one after another the picture would begin to fade at the top by the time the last line is written.

To avoid this, the first frame carries the odd numbered lines and the next frame carries the even numbered lines. This provides uniformity in the picture and this is called interlacing. TV receivers require a source to time the rapid succession of frames on the screen.

Designers decided to use the Mains power supply frequency as this source for two good reasons. The first was that with the older type of power supply, you would get rolling hum bars on the TV picture if the mains supply and power source were not at exactly the same frequency. The second was that the TV studio lights or for that matter all fluorescent, non incandescent lights flicker at the mains frequency.

Since this flicker is much higher than 16 times per second the eye does not detect it. Another technical aspect is that the alternating color information — Hanover bars — can lead to grainy pictures if there are extreme phase errors. This can even happen in PAL systems, especially if decoder circuits are not properly aligned, or with early-generation decoders. However, extreme phase shifts of this nature are seen more often in ultra high frequency UHF signals less robust than VHF , or in areas where terrain or infrastructure limit transmission paths and affect signal strengths.

PAL lines go out at 50 fields per second since Europe uses a 50 hertz power supply , i. PAL televisions produce 25 frames per second that causes motion to be displayed faster. More lines means more visual information , which equals better picture quality and resolution.