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Tektronix provides test and measurement instruments, solutions and services for the computer, semiconductor, military/aerospace, consumer electronics and education industries worldwide.
The dialog normalization value is a Dolby Digital parameter that describes the long-term average dialog level of the associated program. It may also describe the long-term average level of programs that do not contain dialog, such as music. This level is specified on an absolute scale ranging from –1 dBFS to –31 dBFS. Dolby Digital decoders attenuate programs based on the dialog normalization value in order to achieve uniform playback level.
Industry:Entertainment
A file format that represents bitmap images in a device-independent manner. Bitmaps can be represented at 1, 4, and 8 bits-per-pixel with a palette containing colors representing 24 bits. Bitmaps can also be represented at 24 bits-per-pixel without a palette in a run-length encoded format.
Industry:Entertainment
a) This nonlinear distortion is often referred to as “diff gain” or “dG.” It is present if a signal’s chrominance gain is affected by luminance levels. This amplitude distortion is a result of the system’s inability to uniformly process the high-frequency chrominance signals at all luminance levels. The amount of differential gain distortion is expressed in percent. Since both attenuation and peaking of chrominance can occur in the same signal, it is important to specify whether the maximum over all amplitude difference or the maximum deviation from the blanking level amplitude is being quoted. In general, the NTSC measurement standard defines differential gain as the largest amplitude deviation between any two levels, expressed as a percent of the largest chrominance amplitude. When differential gain is present, color saturation has an unwarranted dependence on luminance level. Color saturation is often improperly reproduced at high luminance levels. The Modulated Ramp or Modulated Stair Step signals can be used to test for differential gain. b) The amplitude change, usually of the 3.6 MHz color subcarrier, introduced by the overall circuit, measured in dB or percent, as the subcarrier is varied from blanking to white level.
Industry:Entertainment
a) This nonlinear distortion is often referred to as “diff phase” or “dP.” It is present if a signal’s chrominance phase is affected by the luminance level. It occurs because of the system’s inability to uniformly process the high-frequency chrominance information at all luminance levels. Diff Phase is expressed in degrees of subcarrier phase. The subcarrier phase can be distorted such that the subcarrier phase is advanced (lead or positive) or delayed (lag or negative) in relation to its original position. In fact, over the period of a video line, the subcarrier phase can be both advanced and delayed. For this reason, it is important to specify whether “peak to peak diff phase” is being specified or “maximum deviation from 0” in one direction or another. Normally the “peak to peak diff phase” is given. dP distortions cause changes in hue when picture brightness changes. Colors may not be properly reproduced, particularly in high-luminance areas of the picture. b) The phase change of the 3.6 MHz color subcarrier introduced by the overall circuit, measured in degrees, as the subcarrier is varied from blanking to white level.
Industry:Entertainment
DPCM is a source coding scheme that was developed for encoding sources with memory. The reason for using the DPCM structure is that for most sources of practical interest, the variance of the prediction error is substantially smaller than that of the source.
Industry:Entertainment
A special filter sometimes also called a “diff step” filter that is used to measure luminance nonlinearity. When this filter is used with a luminance step waveform (see the waveform discussed in the Luminance Nonlinearity discussion), each step on the waveform is translated into a spike that is displayed on the waveform monitor. The height of each spike translates into the height of the step so the amount of distortion can be determined by comparing the height of each spike. Refer to the figure below.
Industry:Entertainment
Diffuse light is the light reflected by a matte surface; without glare or highlight. It is base on relative orientation of surface normal and light source positions and luminance.
Industry:Entertainment
Digicipher is a compression and transmission technology from General Instrument, dedicated to Digital TV distribution via satellite.
Digicipher video coding is based on DCT like MPEG, but does not use Bpictures.
Instead, it uses a so-called adaptive prediction mode. Digicipher 1 was the first incarnation and is still used today by many providers since it was the first commercially available digital compression scheme.
Industry:Entertainment
General Instrument’s latest distribution system and is the standard for 4DTV product. DC2 uses standard MPEG-2 video encoding, but just about everything else in this “standard” is unique to DC2. For example, DVB/MPEG-2 uses Musicam for audio whereas DC2 uses Dolby AC-3. Despite using the same video standard, DVB/MPEG-2 and DC2 signals are totally incompatible and no receiver can currently receive both.
Industry:Entertainment
Patented circuitry within the Vista switcher, which allows the insertion of a digital effects device within the architecture of the switcher.
This allows multi-channels of digital effects to be used on a single M/E, which would otherwise require 3 M/Es.
Industry:Entertainment
