| Appendix A: Glossary |
Dot Clock | ' The maximum frequency of the pixel clock. Also known as pixel clock rate. |
| ' The Enhanced Extended Display Identification Data standard, established by VESA, |
| enables properties (such as resolution) of a display device to be detected by the |
| display card in a controlling device such as a PC. The PC, in turn, can then output in a |
| matching format to fill the display. Some sources used with the projector are VESA E- |
| EDID reported. |
Flicker | ' A very rapid variation in image brightness caused by a frame rate that is too slow. |
| (See Interlace) See also Lamp Flicker. |
| ' The intensity of visible light per square foot. |
| ' The luminance (brightness) which results from one |
| on a perfectly diffuse surface. |
Frame Rate | ' The frequency at which complete images are generated. For |
| the frame rate is identical to the vertical frequency. For interlaced signals, the frame |
| rate (also known as field rate) is one half of vertical frequency. |
Gain or Screen Gain | ' The ability of a screen to direct incident light to an audience. A flat matte white wall |
| has a gain of approximately 1. Screens with gain less than 1 attenuate incident light; |
| screens with gain more than 1 direct more incident light to the audience but have a |
| narrow viewing angle. For example: An image reflecting off a 10 gain screen appears |
| 10 times brighter than it would if reflected off a matte white wall. Curved screens |
| usually have larger gain than flat screens. |
GPIO ' General Purpose Input Output, used for remote control of a limited number of | |
| programmable functions by direct signal or |
HDTV ' | |
| line progressive formats with a 16:9 (i.e. 1.77) aspect ratio. |
Help Text | ' A display of help information regarding the current task or presentation. |
Horizontal Frequency | ' The frequency at which scan lines are generated, which varies amongst sources. Also |
| called horizontal scan rate or line rate. |
Horizontal Offset | ' The difference between the center of the projected image and the center of the |
| projector lens. For clarity, offset is often expressed as the maximum amount of the |
| image that can be projected to one side of the lens center without degrading the image |
| quality. Horizontal offset ranges can be affected by the type of lens in use, and |
| whether or not the image is offset vertically at the same time. |
Hot Spot | ' A circular area of a screen where the image appears brighter than elsewhere on the |
| screen. A hot spot appears along the line of sight and "moves" with the line of sight. |
| High gain screens and rear screens designed for slide or movie projection usually have |
| a hot spot. |
Input | ' A physical connection route for a source signal, described by a |
| representing 1) its switcher/projector location and 2) its slot in the switcher/projector. |
Input Signal | ' Signal sent from a source device to the projector. |
RPMSP &