1. D.C. RESTORATION
The sampling process that reestablishes the D.C. and the low frequency components of a video signal.
2. DB ( Decibel )
Uma medida da relação do poder de dois sinais, utilizada para medir a intensidade do som. É igual para dez vezes o logarítmo da relação dos dois sinais.
3. DELAY
Atraso resultado por uma demora na velocidade de transmissão dos vários componentes de freqüência de um sinal por causa de seus tempos diferentes de viagem entre transmissão e a recepção de um circuito
4. DENSITY
A measure of the light-transmitting or reflecting properties of an area. It is expressed as the common logarithm of the ratio of the incident light to the
transmitted light (or the reflected light). There are many types of density such as Diffuse Density, Double Diffuse Density and Specular Density. Each type
depends upon the geometry of the lens optical system.
5. DEPTH OF FIELD
The front to back zone in a field of view which is in focus in the televised scene. With a greater depth of field, more of the scene, near to far, is in
focus. Increasing the f-stop number increases the depth of field of the lens. Therefore, the lens aperture should be set at the highest f-stop number usable
with the available lighting. The better the lighting, the greater the depth of field possible. In other words, the depth of field is the area in front of the camera which remains in focus. The larger the f-number the greater is the depth of field.
6. DETAIL CONTRAST
The ratio of the amplitude of a video signal that represents high frequency components to the amplitude of the components that represents the reference
low frequency. It is usually expressed as a percentage at a particular line number.
7. DETECTOR
An electrical circuit or device used to remove the modulation from a carrier signal.
8. DISPLACEMENT OF PORCHES
Any difference that exists between the level of the front porch and the level of the back porch in the video signal.
9. DISSIPAÇÃO
Uma perda de energia que acontece quando uma certa quantia de energia elétrica é convertida em calor por um dispositivo. Está normalmente expresso em watts.
10. DISTORTION
A deviation of the received waveform from that of the original transmitted waveform.
11. DRIP-PROOF ENCLOSURE
An enclosure that is so constructed or protected that its successful operation is not interfered with when falling drops of liquid or solid particles strike the
enclosure at any angle from 0 to 15 degrees from the downward vertical.
12. DRIPTIGHT ENCLOSURE
An enclosure that meets the requirement of a drip-proof enclosure and in addition does not allow liquid or solid particles to penetrate inside either
directly or by striking and running along a horizontal or inwardly-inclined surface.
13. DUST-TIGHT ENCLOSURE
An enclosure that is so constructed that dust will not penetrate reside.
14. DUSTPROOF ENCLOSURE
An enclosure that is so constructed or protected that dust will not interfere with its successful operation.
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