Karbosguide.com - Module 7a.5

Adjusting the monitor

The contents:

  • Multi Sync
  • Color adjustments
  • Screen savers
  • Environmental standards
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    • The multisync screen with digital control

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    All modern screens are of the multisync type. This means, that the screen adjusts itself to the signals received. The individual model has a minimum and maximum horizontal scan frequency. As long as the signals are received within that spectrum, it adjusts itself to the signals.

    When the screen receives signals at any given frequency, these signals must be adjusted to fill the screen 100%. That is done through the digital controller found in modern screens. Older screens would show a clear black border surrounding the image, whenever the resolution was changed to, lets say 800 x 600 and that is very irritating.

    To enable adjustment to maximum screen utilization, the screen must have digital controls electronics. These adjustments are made on the screen control panel. We are talking about:

  • Horizontal and vertical size, to have the image fill the maximum usable screen area.
  • Horizontal and vertical positioning, to center the image.
  • Compensation for trapezoid and pin cushioning.
  • Colors and light intensity.

    The adjustments can look like this:

    Adjustments
    Symbols
    Horizontal
    and vertical position
    Horizontal
    and vertical size
    Trapezoid
    and pin cushioning

    Often screens are preset to a choice of different possible adjustments. In these preset conditions, the image will immediately appear perfect.

    However, when you set up a monitor to work under non preset conditions you have to adjust the image yourself. Once that is done the monitor will remember your settings.

    There are no international standards for the design of these digital controllers. They are quite different from monitor to monitor and not all easy to work with. However, working with adjustments is a minor problem, relative to other monitor qualities.

    Color adjustments
    The screen can show the colors in different heat ranges. The better screens with digital controllers usually have at least two temperature ranges to choose from. I prefer 6500 degrees. 9300 is somewhat colder.

    Similarly, some video cards can adjust the screen color temperature like Matrox here:


    You should try the different color temperatures. They have a significant effect on the image appearance.

    Aperture grill pitch
    Often you see the term dot pitch or aperture grill pitch. It is measured in millimeters. The numbers indicate the average distance between individual screen dots. The smaller the better. That provides a finer grain screen. For large CRT monitors (21"), the dot pitch can be 0.31 mm or 0.28 mm.

    Otherwise, a dot pitch of 0.28 mm or 0.25 mm is considered sufficiently good for ordinary 15" and 17" screens. A few monitors offer 0.22 mm dot pitch.

    Screen savers
    Early monitors had low quality phosphor coatings. That could cause a screen image to "burn-in" if left unattended. You could clearly see that in work places, where the PC was used for only one program. That program image remained clearly on the screen, after the PC was shut down.

    That led to screen savers. In my recollection, Norton's Commander was one of the first of this kind. After a selected number of minutes without activity, the screen switches to moving stars, as if you were flying through space. This prevents the regular image from burning in.

    CRT monitors have improved a lot since then - the screen image will not "burn in" in a modern CRT. At the same time, screen savers have developed into an art form of their own. Windows is born with a number of choices in screen savers. Also, many programs include a screen saver or two as an extra feature . Some provide a series of images, such as "celebrity cars," showing movie celebrities with their fancy cars.

    Use the screen savers. They can spice up day-to-day work. And please always use a screen saver with your TFT monitor!

    Environmental standards
    Screen radiation is a pollutant. There is no concrete evidence that screen radiation can cause illness. However, artificially generated radiation must be unwelcome in our environment. Consequently, industry standards have been developed for acceptable radiation levels.

    Since the early nineties, the Swedish MPR-2 standard established limits for monitor electrostatic radiation.

    Since then came the stricter TCO-92. It limits the permitted amount of low level radiation and establishes standards for electrical and fire safety. Usually TCO means Total Cost of Ownership but here it refers to the Swedish Confederation of Professional Employees (Tjänstmännens Central Organisation). They defined strong standards for emissions.

    Finally, we have TCO-95, which is the strictest standard. Similar to TCO-92, it also includes regulations on ergonomics (including refresh rates), maximum energy consumption, environmentally friendly production and recycling facilities. The best screens comply with this standard. Screens adhering to the TCO standards are more expensive. Obviously since they are better screens.

    The flat TFT screens do not emit any radiation at all and they consume considerably less energy than the radiating screens. This is another indication that TFT may be the standard screen of the future.

    The VESA DPMS system is an energy saving technology, which includes both screen and video card. A modern 17” screen consumes about 100 watt in normal use. With DPMS the screen switches to two energy saving modes. First, power consumption drops to 25 watts and finally again drops to 8 watt.

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    To learn more

    Read about sound cards in Module 7c.

    Read about digital sound and music in Module 7d .

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