Introduction To A/V Connectivity

This presentation targets electronics industry professionals who are just starting down the path of audio and video technology and integration. Participants will learn about fundamental differences in video and audio signal topology, the relationship between various computer, consumer and commercial analog video systems, an introduction to digital video and the TMDS environment, and a review of the various cabling and connectivity needs and best practices associated with integrating A/V technology into projects. This presentation will provide an overview ranging from line-level analog signals, through PCM, PWM and algorithm-compressed audio standards, and even speaker level signals including low impedance, 25-volt and 70-volt technologies.

Transcript

1. Today’s Webinar: Introduction to A/V Connectivity Lastar Is A Leading Manufacturer Of Low-Voltage Connectivity and Cabling Solutions Presented to you by: Cables To Go & Quiktron Are Sister Companies Of Lastar
2. Today’s Webinar: Introduction to A/V Connectivity Lastar: •Was established in 1984 •Has more than 800 employees •Developed award-winning, RapidRun www.CablesToGo.com www.Quiktron.com www.RapidRun.com Visit www.lastar.com for the complete story
3. Introduction To A/V Connectivity An Overview Of Contemporary A/V Infrastructure Requirements
4. Our Agenda • Basic Video Concepts – Aspect ratio and image shape – Understanding resolution and pixels – Basic electrical concepts important to A/V installation • Analog Video – Composite and component analog video – Computer display video topology • Analog Audio – Single-ended audio – Balanced audio • Digital Audio Basics • Digital Video Basics
5. What is A/V Connectivity? • A/V is “Audio & Video” – This includes control requirements for the A/V products – A/V is primarily point-to-point “back end” connectivity dealing with signal flow between source devices and video displays with audio support • A/V Connectivity is Implemented as a Separate System from an Enterprise’s Computer/Data and Telecommunication Infrastructure • “Convergence” Describes the Combining of A/V and IT Technologies and Infrastructure – Network connections are the new “broadcast” for both internal and external content – Network connectivity may offer control or monitoring capability for A/V devices but does not replace dedicated A/V connectivity
6. Elements of a Video Display • Resolution – Amount of detail a display can produce – Measured in lines or pixels – Higher number = more detail • Aspect Ratio Describes Screen Shape – Width of a screen : height of a screen – “Standard” displays or “academy ratio” • 4:3 or 1.33:1 – “Widescreen” displays come in multiple versions • 16: 9 or 1.78:1(DVD widescreen) • 16:10 or 1.6:1 (computer widescreen) • 2.35:1 (anamorphic widescreen) • Display Type – CRT – analog by nature – The following are fixed pixel displays and are digital by nature • LCD • Plasma • Projection 480 Lines, 4:3 720 Lines, 16:9
7. What Is A Pixel? • Pixel = Picture Element – A series of “dots” that, when viewed from a proper distance, are perceived as a complete image – Newsprint, comic books and pop art such at the Roy Lichtenstein image shown to the right are examples of pixelated print images – This is a true “digital” image as each discrete component is either on (1) or off (0) • On a Flat Panel Display, Discrete LCD, LED or Mirror (DLP) Elements are Illuminated in a Specific Sequence to Create an Image
8. Analog Video Signals • Black & White – Luminance or detail of video image – Luminance is defined by bandwidth • Approximately 80 “lines” of horizontal resolution per 1 MHz of bandwidth • Color – In analog, color is added as a separate signal riding at lower frequencies – 3.58 MHz “color burst” limits analog color resolution on composite signals to about 240 “lines” of horizontal resolution – To improve picture quality, more conductors (with resulting higher bandwidth) are needed • Component Video – RGB are the colors from which all video images are constructed • RGB + sync also describes commercial component connectivity – YPrPb is the consumer component connection • Luminance (Y) and phase-opposite (Pb/Pr) color elements • Computer Video – Is always transmitted in RGB format – RGB + sync is the basis for all computer (aka VGA) connections
9. What is a 75-ohm Cable, Why is it Important to Video and Why Should I Care? • Electrical Impedance is the Measure of the Opposition that an Electrical Circuit Presents to the Passage of a Current when a Voltage is Applied – Impedance is measured in ohms (Ω) • 75-ohm coaxial impedance is set by the ratio of the cable’s conductor diameter to dielectric diameter – Proper impedance matching allows full transfer of signal power and purity • Characteristic impedance is partially responsible for the length limitations we face in connecting analog devices to displays • All Analog Video Signals are Designed to Operate in a 75 Ω Environment – Includes composite, component and computer (VGA) signals
10. Coaxial Cable Construction • Coaxial Means “Sharing a Common Axis – An inner conductor surrounded by a flexible, tubular insulating layer, which is in turn surrounded by a tubular conducting shield • Coaxial Cable Differs from Other Shielded Cables Used for Carrying Lower-frequency Signals, such as Audio Signal – The dimensions and shape of the cable are controlled to give a precise, constant conductor spacing resulting in proper impedance • Composite, S-Video, Component and Computer Video Connecting Cables All Use Varying Quantities of Coaxial Conductors to Transport Clean Signals Between the Source and Display
11. Composite Video • Carried Over a Single Coaxial Cable – RCA connection on most consumer and cross-over devices – BNC connection on many commercial devices • B&W and Color Information are Carried on the Same Cable – Color information is lower in frequency, extending to 3.58MHz – B&W information provides detail and can extend to 6MHz – Limited to about 500 lines of resolution with the best equipment
12. Upping the Ante, S-Video • By Using Two or More Wires to Transport Color and B&W Information Separately, We Can Improve Picture Quality – S-Video uses two coaxial conductors to transport B&W (detail, luminance) and color (chrominance) separately – S-Video improved color quality, but not overall system resolution – Uses 4-pin DIN plug – Largely obsolete today
13. S-Video Cable Construction
14. Component Video • Maximum Analog Performance is Achieved by Using 3 Coaxial Conductors – There are multiple component connections that can be described by the signal content or by how system sync is maintained • RGB – Red, Green, Blue where each primary color is carried on its own coaxial connection • Sometimes knows as sync on green – RGBs adds a 4th conductor to transport sync signals – RGBHV add a 5th conductor to transport horizontal and vertical sync individually • This is the basis for all computer video connections • Consumer Component – YPrPb is luminance (Y) and phase opposite color pairs (Pr and Pb)
15. Computer Graphics are Analog • VESA is the Video Electronics Standards Assoc. – HD15 = high density DBsub15, 3 rows of 5 pins It’s important to be precise! There is another connector called the DB15, which is not as common. The DB15 only has two rows of pins. Many times a customer will refer to an HD15 connector as a “DB15” • Signals Carried Include Red, Green, and Blue Video, Plus Horizontal and Vertical Sync Signals – Newer DDC standards also specify additional signals called ID bits, which allow a monitor to identify itself to a computer
16. Computer Video • A Video Graphics Array (VGA) Connector is Composed of Three- Rows and 15-Pins – Uses RGBHV plus additional conductors for DDC – DDC (display data channel) allows communication between source and display that negotiates the right resolution format for the monitor – Requires pin 9 on the DSub15 connector to be active • VGA Resolutions Can Range from 640×400 Pixels up to 2048×1536 Pixels
17. Analog Audio Signals • Line-Level Signals Describe the Communication Between a Source Component and Amplifier or Switcher – Single ended signals are typically carried on an RCA or 3.5mm TRS connector – Balanced signals use XLR connectors • Microphone Signals are an Order of Magnitude Smaller than Line Level and Need Additional Amplification Before Switching and Routing – Typically use XLR, but some less expensive microphones may use ¼ phone plugs • Speaker Level Signals are an Order of Magnitude Larger than Line Level – Typically use bare wire or speak-on connections For A Complete Understanding Of Audio And Speaker Level Connections, Ask Your Presenter About Our Additional Training Modules.
18. Audio Interconnect Construction
19. Digital Audio Signals • S/PDIF Sony Phillips Digital Interface – Common on consumer electronics devices – Two connecting systems commonly used • Coax, which uses a single RCA connector and looks electrically much like a video signal • Optical, which uses a “toslink” (toshiba optical link) connection – Typically plastic – Length constrained to about 5 meters – Not the same as fiber optics used in IT installations • AES EBU – Professional applications – XLR connector
20. Why Digital Video • Computers, DVD Players and Other Devices Output Video in a Digital Format • Fixed Pixel Displays Use Digital Information to Create an Image • Leveraging Digital Communication Eliminates Complex A/D and D/A Conversions • Digital Video Comes in Two “Flavors” – SDI and HD-SDI are used in video production and broadcast only – All presentation systems use a system called TMDS • Transition minimized differential signalling • TMDS transport supports very high resolutions, such as 9.2 megapixel (3840 X 2400) displays • TMDS supports native 16 million true-color resolution For A Complete Understanding Of Digital Video And TMDS, Ask Your Presenter About Our Additional Training Modules.
21. Digital Video Signals • DVI, Digital Visual Interface – Primarily used for computer and digital signage applications – Carries video only, no audio • HDMI, High Definition Multimedia Interface – Began primarily as a consumer electronics application – Now ubiquitous on most consumer and commercial products – Carries video and digital audio, control and ethernet signals – HDMI fully encompasses DVI-D • Both use the same TMDS encryption system
22. HDCP • HDCP – Digital only method of preventing content piracy • “Analog Sunset” implies analog HDTV transport may be limited in the future • This will effect all computer and source device outputs • Key Authentication and Exchange are Elements of HDCP – Blom’s scheme describes the system for authorizing encrypted digital images – HDCP compliance is critical for presentation system utility • DVI-D, HDMI and DisplayPort Digital Communications All Support HDCP
23. DVI - Digital Visual Interface • Utilizes TMDS – Transmission Minimized Differential Signaling • There are Multiple DVI “Flavors” – DVI-A • Analog signal that is the equivalent of VGA – DVI- I • Includes both analog and digital transport ability – DVI-D, Digital Video Only • Single link supports UXGA – 1920 x 1200 @ 60 • Dual link supports WQUXGA – 3840 x 2400 @ 60
24. DVI-D Cable Construction
25. High Definition Multimedia Interface • HDMI Originally Designed as a Consumer A/V Connection – Now ubiquitous on computers, portable devices, commercial products – Completely incorporates DVI-D for transporting TMDS signals between devices • Utilizes 4 Shielded, Twisted Pairs for Digital R, G, B And Clock Signals – Audio is embedded in video carriers – Supports 24 bit multichannel audio – Adds control capability via CEC – HDMI/E capable of Ethernet connections between devices
26. HDMI Cable Construction
27. DisplayPort • Introduced in 2006 – HP expects that DisplayPort will completely displace VGA and DVI by 2013 • Based on a Micro-Packet Protocol – Allows easy expansion of the standard with multiple data types – Flexible allocation of available bandwidth between audio and video – Multiple video streams over single physical connection • HDMI Compatible Using Passive Adapters Connected to Dual-Mode Ports – Marked with the DP++ logo – Most current DisplayPort graphics cards and monitors support this mode • Supports HDCP • Self-Latching Connector
28. In Conclusion • A/V connectivity encompasses all “back end” communication between source and display or speakers • Analog video consists of color and detail components called chrominance and luminance – S-Video separates the signal into 2 elements – Component video separates the signal into 3 or more elements • RGB, RGBs, RGBHV, YPrPb • All analog video resides on a coaxial, 75-ohm connectivity topology • Analog audio is a 50-ohm connectivity topology • Digital audio “looks” like composite video from an electrical perspective • Digital video leverages the native digital environment of fixed pixel displays • Digital video is found in two common forms – SDI and HD/SDI for production – TMDS for playback and display • High bandwidth digital content protection (HDCP) compliance is necessary on all TMDS installations • DVI-D and HDMI are the two most common forms of TMDS digital video • HDMI adds 8-channel audio and CEC control capability to DVI-D • DiplayPort is used as a media output on computers, but has significant distance limitations • DisplayPort ++ devices can output HDMI