Bài giảng Computer - Chapter 11

Chapter Overview Traditional cathode-ray tube (CRT) monitorsFlat-panel displays (FPD)Display adaptersChoosing and troubleshooting display systems 1Basic Monitor Operation 2Internal CRT Operation 3Screen Resolution and Pitch 4Additional Monitor Considerations The larger the CRT, the more expensive the monitor is.Higher bandwidth equals greater maximum vertical refresh rate (VRR).Interlacing (painting alternate rows) saves money but causes eye strain. 5Power-Saving Features Display Power Management Signaling (DPMS) modes reduce power use when the monitor is idle.DPMS places the monitor in an inactive status if the system is inactive for a specified time.The inactive states areOnStandbySuspendOff 6Tuning the Monitor’s Display 7Monitor Maintenance Do not work inside a monitor; it is dangerous.Properly ventilate the enclosure.Clean the face of the CRT gently.Do not push the monitor beyond its operating guidelines.Use energy-saving features. 8Monitor Troubleshooting Check the cables, including the power and display cables.Check the front panel controls.Check the display drivers and reinstall them, if needed. Try another display adapter.Refer the problem to a specialist. 9Comparing CRT and Flat-Panel Displays 10How Flat-Panel Displays Work FPDs use transparent organic polymers sandwiched between polarizing filters with some form of backlighting.An electrical charge determines if light passes or not.Light-emitting diode (LED) displays have adjoining cells, each with a different color.Active-matrix displays have largely replaced passive-matrix displays (PMDs). 11Emerging Flat-Panel Technologies Electroluminescent displays (ELDs) Emit light from phosphors Have lower-quality color and require higher power usage Plasma display panels (PDPs) Work much like fluorescent lightsUse phosphor films to produce a color imageHave lower contrast and brightness and require higher power usage 12Installing and Maintaining FPDs In general, FPDs are installed and maintained the same as CRTs.You must use a compatible display card.The operating system must have drivers.Multisystem switches might be incompatible.You should wipe the screen with a dry, soft cloth to remove dust.You should use an uninterruptible power supply (UPS) and/or surge protector. 13Early PC Card Display Adapters Monochrome Display Adapter (MDA)Color/Graphics Adapter (CGA)Enhanced Graphics Adapter (EGA) 14Video Memory and Processor Demands The amount of memory determines the amount of color and resolution.Color depth multiplied by resolution determines the amount of memory needed.More colors at a higher resolution require more memory and processor power.Display coprocessors handle tasks that would normally slow down the PC. 15Advanced Display Adapters 16Video Memory Fast page-mode RAM (FPM RAM)Video RAM (VRAM)Extended data out DRAM (EDO DRAM)Window RAM (WRAM)Synchronous graphics RAM (SGRAM)Multibank DRAM (MDRAM) 17Memory/Video Resolution 18Display Drivers Text-based adapters under MS-DOS do not require software drivers.Microsoft Windows, OS/2, and other graphics-rich environments require drivers.Display drivers adjust the refresh rate, resolution, and other features.When installing a new card or operating system, you should check the manufacturer’s Web site for the latest display drivers. 19Choosing a Display System Consider the maximum viewable area that you need.For faster graphics applications, use a fast graphics adapter with VRAM or WRAM.For multimedia systems, consider TV out, TV tuner, and hardware DVD acceleration.If desk space is limited, consider an FPD.Consider the tradeoffs in cost and performance. 20Troubleshooting Display Systems Verify that power and adapter cables are properly attached and that the adapter is fully seated in the expansion slot.Boot the system. If you get an image but the computer does not load the operating system, suspect memory or drivers.Reset the card to 640  480 in 16-color VGA mode at 60-Hz refresh.Make sure you are not exceeding the approved monitor refresh rate.Try a different display adapter or monitor, or test on a different PC. 21Chapter Summary Resolution is a function of horizontal pixels, vertical lines, and the refresh rate.Traditional monitors with CRTs have higher resolutions but take more desk space.FPDs require special graphics adapters.Monitors enclose very high voltages, which can be lethal.The video card is the interface between the expansion bus and the monitor.24-bit cards with VRAM or WRAM are required for true color. 22