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Specifications and Terms
Monitor Bandwidth
In addition to phosphor pitch, bandwidth is a major factor in determining monitor resolution.
Bandwidth relates to the ability of the monitor to display fine detail. Technically, it is the maximum frequency that the monitor can display and is referenced in MHz (megahertz). The higher the resolution you are running, the higher your bandwidth requirement will be.
A simple test as to how well you're monitor is handling the resolution you have or may have it set to is this.
Note: This test should only be performed only if you're monitor type and video card drivers are installed correctly.
In Windows 95,98,ME,XP or 2000, under display properties/settings set you're video card to it's maximum resolution provided. Display either a small grid or a screen full of H's. From a distance of approximately 12 inches observe the brightness of both the horizontal and vertical lines, looking for consistency throughout the screen. Gradually turn down both the brightness and contrast and observe if both the horizontal and vertical lines disappear at the same rate. If they do, the bandwidth of the monitor is adequate for the set resolution. If the vertical lines start to disappear first then the bandwidth of the monitor is inadequate.
Dot Pitch
Simply stated, it's the spacing between the same color red, green, or blue phosphor dots on the screen. Some manufacturers specify aperture grille spacing instead of dot pitch. Basic rule to remember: the smaller the pitch, the better the image.
Horizontal Scan Rate
The Horizontal Scan Rate is the Frequency that roughly corresponds to the number of horizontal lines a monitor can display per second.
Vertical Scan Rate OR Refresh Rate
Number of complete screens displayed per second by the monitor. A 70 Hz refresh rate will provide a flicker-free image. The higher the refresh, the better the image.
Diagonal Viewable Image
Monitor are sold as 14", 15", 17", 19", 20" , 21" and 22". It would stand to reason that if you bought a 15" monitor you're viewing are would be 15 inch's, this however is not the case. Monitors, or for that matter televisions, CRT viewing area is measured diagonally. Upper Left to Bottom Right, OR Upper Right to Bottom Left. The majority of 15" display monitors would measure diagonally about 13.8 inch's., a 17 inch Monitor typically 15.8 inch's, and so on. Part of the reason is that some of the CRT's face is located behind the front bezel or front cover. When purchasing a monitor you would look for the word viewable in the specifications. This will give an accurate accounting of actual viewable screen.
Design Safety Features
1. All monitors have fuses built in, period. It is a design safety feature for the catastrophic failure. What this means is that the fuse is there to open the input AC voltage (think of it as a switch that cannot be turned back on) should you're monitor suddenly short circuit and start drawing large amounts of current. It is also there to prevent fire if this should occur .
Most monitors incorporate Power Loop or Over Current circuitry. This will cause the monitors power supply to shut down should there be a short detected in the output of the power supply.
Many also incorporate Deflection Loop circuitry with fused resistors. If a short circuit develops within the deflection circuit, the fused resistors will open, effectively disabling the offending circuit, preventing further damage to the monitor. If for some reason no deflection has been detected, again the deflection circuit will be disabled, preventing harm to the CRT's phosphor screen.
2. Spot Killer Loop Circuitry inside the newer CRT's is designed to discharge remaining charged particles that have accumulated in the grid of the CRT. The end result is that the CRT is protected against spot burnout and phosphor etching..
3. The OVP (Over Voltage Protect) a special circuit designed to automatically protect against voltage that is too high. A signal pulse, obtained from the High Voltage Transformer, also known as a Flyback transformer is shaped and then fed to a switch controlling the
the input to itself. If the signal pulse becomes too high, indicating excessive high voltage, will disable the input stage from functioning and thus preventing harmful CRT X-ray radiation.
Operational Terms
Safety Standards
Products from respectable manufacturers should comply with a host of standards for electrical safety, ergonomics, radio frequency interference (RFI), and emission. These safety standards are designed to protect you and the environment. Energy Star is a standard in the United States from the EPA (Environmental Protection Agency) defining minimum requirements for reducing energy use in computers and peripherals. Display Power Management Signaling (DPMS) is an increasingly important standard from VESA (Video Electronics Standards Association) designed to reduce energy consumption by monitors. It provides a means of signaling the monitor to power down when not in use. Also of great importance is the MPR-II compliance, which regulates electromagnetic emissions and reduces health risks.
Plug & Play
Plug & Play (DDC 1/2B) compatibility offers significant performance advantages by enabling monitor capabilities, including scanning frequencies and image sizing, to be communicated automatically to the operating system without the use of drivers or diskettes for installation.
On Screen Display or OSD
Newer, more advanced monitors come equipped with an On-Screen Display (OSD) that adjusts all display parameters via an on-screen control panel. Mitsubishi’s OSD allows you to adjust all display set-up parameters and color temperature settings through icon-based, on-screen control panels. It is extremely easy–virtually intuitive–to use because the text is jargon-free and there are only two sets of control buttons – one set to select the panel/function, and another to adjust the settings.
TCO '99: The Road to a "Green Office" and "Green World"
The invention of the computer has brought many benefits as well as many problems. The problems brought have been particularly noticeable with regard to the environment, and cultural behavior. The issue of lessening those destructive aspects of computerization has become, to many countries, the most important question that now needs to be faced. In response to this, one group TCO (The Swedish Confederation of Professional Employees) has produced the most comprehensive set of standards for computers and environmental safety; these standards can be put into the four categories below.
Ergonomics
Many reports point to the health risks for both the body and the eyes of long-term computer use, even suggesting that vision can be permanently impaired. TCO has established a set of product specifications for industry to adopt. They are strict in their scope, and, if one wants to obtain the "good product", standards need to be adhered to, to the letter. For monitors, they include guidelines on refresh rate, flicker, jitter, and edge focus degradation.
Energy
When using a computer we often leave our desks to attend to other affairs. More often than not, because we neglect to close our computers< huge amounts of energy are wasted. In order to solve this problem TCO has established another standard:
If a computer remains idle for a fixed period of time it will automatically enter "Power-Saving" mode. In this mode signals will be dropped (most notable the Horizontal Sync) from being applied to the monitor. The monitors internal circuitry detects this missing sync signal, and enters it's Power Saving Mode, thus reducing the amount of energy consumed, to typically 5 Watts or less, achieving our energy saving objective.
Emissions
As of the present there are still no official reports that are able to state conclusively the level of harm caused to the body by the waves of an electromagnetic field. It is however widely accepted by all that one should limit exposure to these rays, to as little as possible. Accordingly the TCO standard on emissions is extremely strict.
Ecology
Computers have an exceptional growth rate and short life span. Most problems are derived from the ever-increasing enormous rate at which they are being disposed, and the harm to the environment, which goes hand-in-hand with the disposal of obsolete machines. In response to this TCO has developed a series of regulations that attempt to decrease the conflict between computers and nature.
a) Decrease the use of harmful heavy metals, such as mercury.
b) Increase the number of parts that are recyclable so the machine is more environmentally friendly.
In summary, the advantages of using a computer that has passed through TCO 99 regulations are:
A) Consumer
The high screen quality means harm to the eyes is reduced. The safety of the user is assured because of reduced electromagnetic field emissions. Reduced radiation emissions mean a more comfortable working environment.
B) Environment
Energy saving Reducing the dispersion of harmful entities such as mercury Improved Ratio of recyclable parts
Conclusion
Irrespective of, if you are simply concerned with user issues, or a person concerned with environmental protection, one thing is clear, buying products that are TCO approved are in every ones' best interest.
USB, what's it doing on my Monitor ?
The term USB
The term USB has already become a familiar one. Its specifications became standardized a long time ago and its inclusion into the motherboard standard practice. However, only recently has there been any real discussion about USB and its uses, and, consequently, the one-after-another introduction of peripheral devices with attached USBs.
So "What is USB?" and "Why do we need it?" In the section below we will examine among others these questions.
What is USB?
USB is a new interface standard for assisting the use of Windows 98 and Intel. It was designed as a low speed transmission interface (12 Mb/sec). Its job was to improve the mess of wires that build up behind your PC. It can replace the parallel port and serial port. Its aim is to only use one wire to make an attachment. If the series of connections is continued to the maximum the most will be 127 possible attached devices.
Why USB? What are its advantages?
a) It decreases the complication in connecting peripheral devices to the PC. Sometime ago the PC was a simpler machine with fewer peripheral attachments. Now the number of possible attachments is enormous; keyboard, mouse, speaker, scanner, printer, printer, modem and digital camera to name just a few. Consequently, the number of wires at the back of the PC has become too many to arrange and manage effectively; sometimes there are not even enough output ports to use. With USB all you need to do is attach a cable into the back of a PC and then into a USB Hub and all peripheral devices with USB plugs can also be attached.
USB unifies the connector design of peripheral attachments so that it is not necessary to worry about which connector connects with which, or if you have connected them incorrectly. There is also no need to purchase an interface card so you can save the interface card money and there is no need to spend time inserting the interface card into the PC case. Therefore this clearly saves a great deal of time and money.
b) Assists Plug and Play
The first time you use a USB attachment it is usually necessary to install a driver (unless Windows already has the driver for this attachment built-in). However, once this driver is installed you are permitted, without having to first close your PC, at anytime, detach or re-attach peripheral devices. The system will automatically examine the USB attachment and open it.
USB peripheral attachments
At the moment peripheral attachments that include USB are; keyboard, mouse, speaker, scanner, printer, modem, storage devices (tape drives as well as Hard drives) and digital cameras to name just a few.
What is the USB Hub?
One look at the word hub and we know it is a device into which all attachments with USB connectors can be plugged. We can think of USB attachments, and the way they are arranged, in the same way we think of Internet architecture. Two USB connecting ports are usually integrated into the motherboard of the PC, however, if you only have two connecting ports there is of course no way that the present requirements for peripheral devices can be fulfilled. In other words, the peripheral devices are not attached to the back of the PC but instead to the USB hub. The hub is a box with USB ports, generally four ports, USB attachment ports. It has it own electric power cable requirements and a cable between it and the PC's USB port.
The relationship between the Monitor and USB Hub.
As we know USB tidies the arrangement of the peripheral devices wires behind the PC. However, if all peripheral device connectors become USB then the problem still remains of connecting them all; the position merely changes from the back of the PC to the USB hub. At present the most convenient place to put the hub is on the monitor. The reasons are threefold:
a) The distance between the monitor and the user is, when compared to other devices, relatively close. Therefore, attaching USB connectors is exceptionally convenient.
b) There is adequate space to design the USB HUB into the monitor.
c) The monitor can act as a source of power for the hub so there is no need to rely on, or create, an additional outside source of power.