Traditionally video signals have been transmitted along cables in the form of lower energy electrical impulses. As new technologies emerge we are

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Anis Morris
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2 Traditionally video signals have been transmitted along cables in the form of lower energy electrical impulses. As new technologies emerge we are seeing the development of new connection methods within video equipment. 25 years ago things like RCA and Coax (CATV) connections were cutting edge. Now these types of connectors are outdated and provide the lowest quality of signal transmission. In this module we will start off by talking about some common terms used when discussing video signals. We will then discuss the various types of connection systems currently used to transmit video signals 3

3 Some video signals (such as S-Video) are made up of two portions Chrominance and Luminance. Chrominance is the colour portion of the signal. It carries the saturation and tint (hue) information for any given point in the image and tells the video display (TV, monitor etc) what colours to use to reproduce the image. Luminance is the black and white portion of the signal. It carries the information for brightness, darkness and contrast. The luminance is what gives the colours their depth and contrast. The luminance ranges from pure black to pure white and when combined with the chrominance a complete video image is developed. The Chrominance and Luminance information is transmitted separately to improve signal quality and signal strength, which in turn leads to a better image being produced at the display. Chrominance is abbreviated with the letter C, and Luminance with the letter Y. Most televisions / displays will allow you to adjust the chrominance (tint) and luminance (brightness) of the image to correct for image quality issues and aging components (ie as the TV gets older you may need to adjust the settings to eliminate colour distortions). 4

4 Have you ever looked at a flat screen TV or computer monitor and seen numbers like 480i, or 1080p? Ever wonder what these numbers mean? These numbers tell you the details of the resolution and type of video your TV or monitor is capable of re-producing. Keep in mind though that just because your TV or monitor is rated at 1080p (for example) does not mean every image you see on it has this resolution and video type. That s just what the TV or monitor is capable of reproducing! In order to fully enjoy the capabilities of the video display you need a video source capable of producing a high quality image something like an HD DVD or Blu-ray player for example. So let s break the numbers down a bit. The digits indicate the number of lines of vertical resolution the display unit has. The higher the number, the more detailed an image it s capable of displaying. What the number tells you is how many physical lines of pixels are on the screen from top to bottom. A 1080 TV has 1,080 vertical lines. But let s back track for a second because... what s a pixel? LCD / Plasma TV s and computer monitors are made up of tiny squares or pixels. Each of these pixels is capable of producing a wide array of colours. Images are produced on the screen by affecting the colour of each pixel one by one according to information transmitted in the video signal and decoded by the signal processor in the monitor or TV. The letter found after the vertical lines of resolution number on a flat screen display indicates the type of video or more accurately the type of scanning used to create the images. There are 2 types of scanning currently used in flat screen displays Interlaced Scan (i) and Progressive Scan (p). Interlaced Scanning separates each frame of video into two fields odd and even. The odd field addresses the odd numbered vertical lines (lines 1, 3, 5, 7, etc etc) and the even field addresses the even numbered lines. This method of scanning improves image quality by removing flicker from the image shown on the display. This gives the perception of a more detailed image. Progressive Scanning draws the lines of the image in sequence i.e. 1,2,3,4,5 etc etc. Progressive scanning provides much higher resolution images and faster image processing than Interlaced Scanning but twice as much image data has to be transmitted from the source device to the display. 5

5 There are a number of types of connections used in video systems today. Now that we ve explained a few common video terms let s look at the different types of Video Connections. We ll start with the ones which provide the lowest quality signals, and work our way up to the best! Of all the different types of video connections used today, one of the oldest and most common is RF or CATV - connections. This connection type provides the lowest image quality of any that are in use today. It is the standard connection used in today s Cable TV and Satellite TV systems and uses f-type connectors which crimp on to the ends of the cable. CATV type connections are also used to make connections between TVs and components such as your cable box, satellite receiver, or VCR. In this system both the audio and video signals are transmitted on the same cable. 6

6 Composite Video is a step up from CATV connections, but it still provides the 2nd worst image quality of all the various connection types in use today. In Composite video all aspects (all colour information as well as horizontal and vertical synchronization data) of image are combines in 1 signal. In a composite video connection only the video image signal is transmitted through the wire, the audio signals are transmitted separately through separate cables. This type of connection typically uses RCA connectors (yellow or black coloured plugs or insulators are used to indicate Composite Video connections). BNC connectors are also used on some devices such as projectors. Both types of connectors are typically soldered to the ends of the cable to ensure the best possible signal transfer between the cable and the connectors. Composite Video provides low detail image, but is one of the most common connections used in consumer electronics. You will find Composite Video connections on things like TV s, VCR s, and DVD players. Even some digital cameras have a Composite Video output which allows you to connect the camera directly to you TV to view your photos! 7

7 S-Video (sometimes referred to as Y/C) transmits video signals by separating the chrominance (C) and Luminance (Y) portions of video signal. This results in a far superior picture quality when compared to CATV or Composite Video connections. By separating the Y and C components of the signal distortions like colour errors and low image detail can be eliminated. As with Composite Video, S-Video only deals with the transmission of the video image information. Audio signals are transmitted separately. S-Video connections are quite commonly found in use in video displays like TVs as well as video media players such as DVD players and VCRs. S-video connections use special 4 pin connectors which are keyed to ensure proper alignment of the pins when making a connection. 8

8 Component Video splits the video image into components but contrary to popular belief it does not split into red, green, and blue components (even though cable ends are coloured red, green, and blue). Component video splits the image into 3 components Luminance (Y) along with one or more colour-carrying components (Chrominance (C)). Splitting the image in this fashion allows for more precision and speed in mapping and re-producing the image. As with many of the newer video transmission methods, Component Video only deals with the video image information. Audio signals are transmitted separately. Component Video was the first High Definition video format introduced to the market, so many TVs, DVD players, VCRs and gaming consoles include YPrPb inputs / outputs. The YPrPb connections found on most consumer electronics use RCA connectors, but some higher end devices use BNC connectors as they provide a better connection. Component Video provides a much better quality image than S-Video, Composite Video, or RF but it is a lower resolution image than DVI or HDMI (Component Video typically provides a 480i image). 9

9 RGBHV is another form of High Definition video signal, typically used in things like computers and computer peripherals (projectors etc). This type of signal separates the video image into Red, Green, and Blue colour elements and has separate signals for horizontal and vertical synchronization data again, no audio signal is included in this system. Separating the image into 5 elements requires the transmission of much larger amounts of data so the video signal is transmitted on 5 cables R, G, B, H, and V. There are two common types of connectors used for RGBHV video HD 15-pin (computers etc) and BNC (projectors and other peripherals). Many of today s flat screen televisions also have a 15-pin input which allows you to connect your computer to the TV! 10

10 Digital Video Interface (DVI) is a video interface standard designed to maximize the visual quality of digital display devices and digital projectors. This system uses component video approach in the transmission of video signals, but converts it from an analog signal to a digital signal to accommodate both analog and digital display units. There are three different styles of connectors DVI-D (digital only), DVI-A (analog only), and DVI-I (analog and digital). 11

11 High Definition Multimedia Interface (HDMI) is an all-digital audio/video interface. HDMI supports high definition video PLUS multi-channel digital audio on a single cable! The single biggest advantage HDMI connections offer is that the signal is 100% digital which means 0% signal loss between the source and display devices. Other transmission methods like component audio / video will lose some signal strength resulting in reduce image and sound quality. Most High Definition devices (TV s, HD Cable / Satellite receivers, Blu-ray players etc) come standard with an HDMI connection (some may have a DVI connection instead). The current HDMI connector (Type A) has 19 pins and supports video resolutions up to 1080p. A higher resolution connector (Type B) is being developed but is not yet being offered on consumer electronics. The Type B connector has 29 pins to allow for transmission of additional video data and will be able to support resolutions HIGHER than 1080p (the display technology is not yet in place to utilize this higher resolution video). 12

iii Table of Contents

i iii Table of Contents Display Setup Tutorial....................... 1 Launching Catalyst Control Center 1 The Catalyst Control Center Wizard 2 Enabling a second display 3 Enabling A Standard TV 7 Setting