Crutchfield

RF CONNECTION

The RF connection is nothing more than a coaxial cable with an F-Connector on the end. It can be threaded or push-on type.

RGB CONNECTION

The RGB connection can be seen as an RCA type connection or as a DIN connection. No picture of the DIN connection is available at this time.

TELEVISION STANDARDS

NTSC (National Television Systems Committee)

This is the video transmission standard for North and Central America, including Mexico, Canada, and Japan. Its' format is 525 lines of resolution with a 30 FPS (frames per second) refresh rate.

While the signal does contain 525 lines of resolution, only 480 lines are actually visible. The non-visible portion is used to encode Closed Captioning, SAP (Second Audio Program) Broadcast, and Macrovision.

PAL (Phase Alteration Line)

This is the European counterpart to NTSC. It has a higher resolution of 625 lines with a lower refresh rate of 25 FPS. It is the standard for the UK, Western Europe, the Middle East, and parts of Africa and South America.

SEACAM (Systme Electronic Pour Couleur Avec Memoire)

ATSC (Advanced Television Systems Committee)

ATSC is responsible for the DTV (Digital Television) Standard and it covers both High Definition and Standard Definition broadcasts. DTV is going to eventually replace the analog NTSC standards. It is already an active format in several of the larger viewer markets, and is continually becoming more widespread.

ATSC standards call for 18 different picture formats. Here is a chart of all 18 formats.

ASPECT RATIOS

The two primary aspect ratios are 4:3 and 16:9. The aspect ratio is nothing more than the ratio of horizontal size to vertical size.

Most televisions have an aspect ratio of 4:3. With the advent of HDTV, 16:9 (Widescreen) TV's are becoming more and more popular.

Video will be displayed in one of these two aspect ratios. Either one can be dispayed on a TV with a different aspect ratio, but there will be drawbacks.

Here is an example of each aspect ratio and how the picture will appear on a TV.

As you can see, when the format of the video is not the same as the TV, you will end up with a portion of the screen not actually displaying any of the picture (Black Bars). In either case, you are not missing any of the actual picture, it is simply not formatted to fill the entire screen.

The two most common ways to display a 16:9 picture on a 4:3 TV, are Letterbox and Pan & Scan.

Letterboxing retains the complete picture in its' original format. This will give you the "black bars" on the top and bottom of the screen. The benefit of this is that you see everything you were intended to see by the director. The drawback, is that the picture "appears" to be shorter. While the picture is physically shorter than the TV screen, the complete picture is still there.

Pan & Scan crops the original picture and only retains ta portion of it and it is presented ina a 4:3 format. You will normally lose about 1/3 of the original picture when it is presented in a Pan & Scan format. The benefit to this is that you "fill" the whole screen of your 4:3 TV. The drawback is that you lose a portion of the original picture.

PROGRESSIVE SCAN and INTERLACED VIDEO

There are two ways to "paint" the picture on the screen of a TV. One way is Interlaced, and the other is Progressive Scan.

Interlaced

An Interlaced picture is drawn half of the picture at a time. One frame of video is divided into two fields. The first field is all of the odd numbered scan lines, and the second field is all of the even numbered scan lines.

The TV will paint the first field from top to bottom and then it will go back to the top and paint in all of the even numbered lines. So in actuality, only half of the picture is on the screen at any one time. However, this happens so fast, that you see it as one complete picture.

Progressive

With Progressive scan, instead of drawing the odd lines and then the even lines, it draws every line in sequential order. Progressive scan provides a smoother picture with less flicker.

3:2 Pull Down

3:2 Pull Down is nothing more than the conversion of film to video. Film runs at a rate of 24 frames per second. Video runs at a rate of 30 frames per second. You can't simply speed up the film because it will run visibly faster. It would be like playing a 33 1/3 record at 45 speed.

Here is a diagram of what is done.

Closed Captioning

Closed captioning is tect information embedded in the video signal. It requires a special decoder to view. This decoder is typically built into all TV's but is also available as an external device. Closed captioning can be added in after the fact, such as with movies and pre-recorded television programs. it can also be done real time. When this happens, there will be a lag between the actual dialogue and the text information.

Macrovision

Macrovision is a form of copy protection for video that helps to prevent copies of original material, typically VHS and DVD, from being made. Macrovision works by affecting the AGC (Automatic Gain Control) circuit of a VCR.

The AGC monitors the incoming signal and works to maintain a stable signal. If it sees an unacceptable increase or decrease in the signal, it will compensate accordingly. Macrovision incorporates a signal outside the viewable area of the incoming signal. it is generating spikes and dips in the signal and the AGC is contstantly trying to correct for this. Since the visible signal for the picture is not changing, every time the AGC makes a correction, it causes the picture to either get brighter or darker but it is never stable. it is constantly flickering back and forth. The Macrovision signal only affects the video portion, there is no change in the audio. Because of the flickering that happens, the recording becomes uncomfortable to watch.

SAP (Second Audio Program)

This is the audio portion of the program you are viewing, being transmitted in a different lanquage. It can be in any other language but will normally correspond to the most common second language in the area.