Transcript Video.2

Video
10-1
Section Objectives
After completing this section you will be able to:
 Describe the components of the video subsystem
 Differentiate among monitor types including laptop displays
 Define basic monitor theory and terminology
 Describe issues regarding video memory
 Install a video adapter and associated software
10-2
Video Overview
Video should be considered a subsystem that
consists of:
– the monitor
– the electronic circuits which send the monitor
instructions
– the connecting cable
10-3
Video Overview
Video subsystem
Video – Figure 10.1
10-4
Types of Monitors
Different ways of classifying monitors:
– Color or Non-color
– Analog or Digital
– Type of video adapter used
10-5
Types of Monitors
 Monochrome
– First type to be produced
– Project a single color (white, amber, or green) on black
background
– Text-only output, no graphics
 Grayscale
– Display varying shades of black and white
– Used by artists and CAD designers
 Color
– Display up to millions of colors for text and graphics
10-6
Types of Monitors
 Digital
– Accept digital signals from the video adapter
– First monochrome and first two types of color monitors
– Limited number of colors
 Analog
– Utilize analog waveforms to generate colors
– Color variations are limitless
Note: Video adapter must match the type of monitor.
10-7
Types of Monitors
Video adapters/monitor types
Video – Table 10.1
10-8
Monitor Terminology and Theory
 Monitor size
– No industry standard, but traditionally defined as the diagonal length of
the picture tube (or CRT).
– Most common sizes are 15-inch, 17-inch, and 21-inch.
 CRT (Cathode Ray Tube)
– Main part of the monitor.
– Covered by the monitor case which may not allow all of it to be viewed.
 VIS (Viewable Image Size)
– Listed by many manufacturers as the viewable area of the CRT to clarify
the monitor size.
10-9
Monitor Terminology and Theory
 Electron gun
– Directs a beam of electrons at a phosphorous dot on the back of the monitor tube.
• Some monitors have 3, one each for the colors red, green, and blue.
• Other monitors utilize only 1 to direct the 3 color beams.
– When the beam hits the phosphor, the dot glows on the front of the screen.
• All figures, icons, and letters are made up of these glowing dots.
 Dot triad (or dot trio)
– 3 phosphorous dots grouped together at each location on the screen.
– Consists of 1 dot each for red, green, and blue.
– Electron beam hits the dot(s) with varying intensity causing the phosphor to glow
and create different color intensities.
10-10
Monitor Terminology and Theory
 Shadow mask
– A metal plate with holes that keeps the electron beam
directed (or focused) at the proper dot.
 Pixel (short for picture element)
– One dot on the screen created by the convergence of the
phosphorous dot trio.
– Smallest displayable unit on the monitor screen.
10-11
Monitor Terminology and Theory
Video theory of operation
Video – Figure 10.2
10-12
Monitor Terminology and Theory
 Picture cell
– The single image created by 3 different colored phosphorous dots.
 Dot pitch
– The distance between like-colored phosphorous dots on adjacent dot
triads.
– Measured in millimeters.
– Commonly include .39mm, .35mm, .28mm, .26mm, .25mm.
– The lower the monitor’s dot pitch, the smaller the distance between the
dot triads. The lower the number, the better the picture quality.
10-13
Monitor Terminology and Theory
Dot pitch
Video – Figure 10.3
10-14
Monitor Terminology and Theory
 Aperture grill
– Used in monitors and televisions as an alternative method to the shadow
mask using very fine vertical wires instead of holes.
– Allows more electrons to reach the screen, producing deeper color
intensities.
– Requires horizontal stabilizing wires to keep the fine vertical wires from
vibrating or moving and these can be viewed on bright images.
– Minimum acceptable dot pitch for the aperture grill is .25mm.
– Some dot pitch descriptions include:
 Grill pitch, horizontal mask pitch, and mask pitch.
10-15
Monitor Terminology and Theory
Aperture grille
Video – Figure 10.4
10-16
Monitor Terminology and Theory
 Resolution
– The maximum number of pixels of a monitor.
– Illustrated by two values separated by an x, meaning by.
Example of a monitor resolution is 640 x 480.
– 640 = # of pixels that fit horizontally
– 480 = # of pixels that fit vertically
– Depends on the combination of the monitor and adapter.
10-17
Monitor Terminology and Theory
 Refresh Rate
– The maximum number of times a screen is scanned, or redrawn, in one
second, measured in Hz.
 Horizontal scanning frequency (HRR or Horizontal Refresh Rate)
– The speed which the beam traverses the screen and draws one line.
– Measure in kilohertz (kHz) as determined by the video adapter.
– Range from 35 to 90 kHz.
10-18
Monitor Terminology and Theory
 Vertical scan rate (VRR or Vertical Refresh Rate)
– The number of times the electron beam draws from the top-left corner, to
the bottom-right corner, and back again to the top-left, drawing the entire
screen.
– Determined by the capabilities of the video adapter and the monitor.
 Multi-scan monitor (also multi-synch or multiple frequency)
– Can lock onto different vertical and horizontal scanning rates.
 Interlacing
– A monitor that uses interlacing scans first odd numbered pixel rows, then
returns for the even ones on each vertical refresh.
– Causes a flickering screen, but is less expensive than non-interlaced,
which scans all horizontal rows on each vertical refresh.
10-19
LCD (Liquid Crystal Display)
 LCD (Liquid Crystal Display)
– A video technology used with laptops and flat screen monitors.
– The two types of LCD are passive matrix and active matrix.
 Passive matrix (least expensive)
– Made up of rows and columns of conductors, with the pixels located at
each intersection.
– Each pixel has 3 cells in a color monitor, one each for red, green, and
blue.
– Not as bright as active matrix displays.
10-20
LCD (Liquid Crystal Display)
 Active matrix (more expensive)
– Have a transistor for each pixel.
– Number of transistors determine maximum resolution.
– Also known as TFT(Thin Film Transistor), which use three transistors
per pixel, one for each color.
– Brighter than passive matrix.
 Flat panel
– Monitors for desktop computers that use LCD technology.
– Viewing area the same as the LCD measurements.
– Take up less desktop space, and use less power than CRTs.
10-21
LCD (Liquid Crystal Display)
Flat panel versus regular-sized monitor
Video – Figure 10.5
10-22
Video Ports
 DVI ( Digital Video/Visual Interface)
– Interface used on an AGP PCI-E adapter with the better flat panel
monitors.
– DVI port is a 24-pin connector.
 Single link connection – Allows video resolution up to
1920x1080.
 Dual link connection – The use of more pins sends more single
allowing for higher resolution.
 DVI-D – Type of DVI used for digital connectivity only.
 DVI-I – Type of DVI used for both digital and analog monitors.
 HDMI (High-Definition Multimedia Interface) - An upgrade
to DVI which carries both video and audio over the same cable.
10-23
Video Ports
Video Adapter with S-video (TV Out), DVI and VGA Ports
Video – Figure 10.7
10-24
Projectors
Projector – Projects what is being displayed on
the computer onto a larger screen.
The connections for a projector are similar to
those of a video card.
10-25
1-25
Monitor Preventive Maintenance
 Cleaning the screen may be performed using anti-static
wipes.
 Do not get liquid near the edge of the CRT, it may leak
into the monitor.
 The case may be cleaned with a soft dampened cloth
and one of the following:
– Mild household detergent, glass cleaner, or
isopropyl alcohol.
– Spray cleaner onto the cloth, not the monitor.
10-26
Monitor Energy Efficiency
 APM (Advanced Power Management)
– Developed by Microsoft and Intel.
– Allows BIOS to control hardware power modes.
 ACPI (Advanced Configuration and Power
Interface)
– Microsoft introduced on Windows 98, 2000, XP, and Vista.
– Expands control to power modes for CD/DVD drives,
network cards, printers, and other attached devices.
10-27
Screen Savers
 Screen Saver
– Changes the image on the monitor constantly to keep any
particular image from burning into the screen.
– With old monitors, they were a necessity to prevent damage.
– New monitors’ high refresh rates make screen savers
unnecessary.
– LCDs do not need the use of screen savers as they use a
different technology than CRTs.
– Provide a form of entertainment for the computer user.
– Provide password protection for users.
10-28
Video Adapters
 Video adapter
– Controls most of the monitor’s output.
– Use the PCI, AGP, or PCI-E interface.
– Bus connects the video card to the microprocessor.
– The bus interface, microprocessor, chipset, and video
adapter can affect the speed of video transfer to the monitor.
– Upgrading the chipset, microprocessor, and video adapter
can improve video performance.
– Some adapters have a video processor.
10-29
Video Adapters
Video processor (also called a video
coprocessor or video accelerator)
– Assists the video communication between the
adapter and the microprocessor.
– Can be up to 64- or 128-bit processors.
– Controls many of the video functions otherwise
controlled by the microprocessor for faster
performance.
10-30
Video Memory
 VRAM (Video RAM) and WRAM (Windows
Accelerator Card RAM)
– Dual-ported memory (have separate read/write paths) and
can written to and read from simultaneously.
 RDRAM (Rambus DRAM), SGRAM (Synchronous
Graphics RAM), and MDRAM (Multi-bank Dynamic
RAM)
– Single-ported memory that cannot be written to or read from
simultaneously.
10-31
Video Memory
Bits required for colors
Video – Table 10.6
10-32
Video Memory
Video memory requirement examples
Video – Table 10.7
10-33
Installing a Video Adapter
 Make sure you have the correct interface type and an available motherboard
slot.
 Gather required tools.
 Download the latest driver for the video adapter including any video BIOS
updates.
 Make sure the adapter has the driver required for the operating system you’re
using.
 Power off the computer.
 Open the computer and install the video adapter in the proper slot.
 Connect the monitor to the external video connector.
 Power on the computer and install the video driver per the manufacturer’s
instructions and the operating system’s controls.
10-34
Troubleshooting Video
 Try simple solutions first:
– Check power cables and that monitor is turned on.
– Ensure monitor cable is securely connected to the video adapter.
– Check settings and controls.
– Check to see if any new software or hardware has been installed, or if an upgrade
has occurred.
– Replace subsystem components with known good ones.
 Raster
– A monitor’s brightness pattern – a bright white screen.
– If it appears, most likely the problem is the video adapter.
 Troubleshooting tips can be found on page 368 in the book.
10-35
Troubleshooting Video
Flyback transformer
– Component that boosts the voltage to the high levels
the CRT requires.
– Frequently goes bad.
– Check prices before replacing, may be more costeffective to replace entire monitor.
Degausser (or degaussing coil)
– Can remove CRT magnetization.
10-36