Plasma screens are basically a network of red, green and blue phosphors (each triad makes up a single pixel) mounted between two thin layers of glass. Plasma screens use a small electric pulse for each pixel to excite the rare natural gases argon, neon and xenon used to produce the color information and light. As electrons excite the phosphors, oxygen atoms dissipate and create plasma, emitting UV light. These rare gases actually have a life and fade over time. all the phosphor-excited pixels react at the same time, there is never any flicker apparent to the viewer. There's also no backlight and no projection of any kind, so the light-emitting phosphors, result in a bright display with a penchant for rich color and a wide viewing angle.
Glossary of Terms
The audio and video world is changing rapidly. Our glossary of terms should help you decipher the various acronyms and techno-speak that is common in our industry. If you stop by our store, we promise to explain things to you in a clear and concise manner, and you won't need a glossary to keep up. You can click on any of the letters in the alpha index to see terms starting with that letter. Thanks, and we hope to see you soon.
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Active Video
The portion of a video signal that contains picture information.
ADC or AD Converter
Analog-to-digital converter.
Aliasing
1. Distortion in the video signal which may manifest itself in different ways, depending on the type of aliasing:
Spectral aliasing is caused by interference between two frequencies, such as the luminance and chrominance frequencies or thechrominance and field scanning frequencies. It appears as moire or herringbone patterns, straight lines that become wavy, or rainbow colors.
2. Spatial aliasing is distortion that occurs because of limitations in physical resolution of the scanning process. It appears, for example, as straight diagonal lines that become stairstepped or jagged.
3. Temporal aliasing is distortion resulting from information lost between line or field scans. It appears, for example, when a video camera is focused on a computer screen; the video output shows a flickering bar on the computer screen because of the lack of scan synchronization of the camera and the computer.
Amplitude
The magnitude of a signal in voltage or current. Frequently expressed in terms of peak, peak-to-peak, or RMS.
Amplitude modulation (AM)
A method of imposing information on a carrier signal, such as a sine wave, by varying its amplitude.
Analog
An adjective describing any signal that varies continuously as opposed to a digital signal, which contains discrete levels.
Analog component
Another name for component video, such as RGB or Y, R-Y, B-Y as opposed to digital component video.
Archive
Off-line storage of video/audio onto back-up tapes, floppy disks, optical disks, etc.
Asynchronous
Lacking synchronization. In video, a signal is asynchronous when its timing differs from that of the system reference signal. A foreign video signal is asynchronous before it is treated by a local frame synchronizer.
ATSC
Advanced Television Systems Committee (USA). A group whose charter is to develop voluntary national standards for high definition television.
Attenuation
The decrease in amplitude of a signal.
Attenuator
A circuit that provides reduction of the amplitude of an electrical signal without introducing appreciable phase or frequency distortion.