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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.
a) Binary polynomial. Used to generate check information on blocks of data. Similar to a checksum, but is harder to generate and more reliable. b) Used in data transfer to check if the data has been corrupted. It is a check value calculated for a data stream by feeding it through a shifter with feedback terms “EXORed” back in. A CRC can detect errors but not repair them, unlike an ECC, which is attached to almost any burst of data that might possibly be corrupted.
CRCs are used on disks, ITU-R 601 data, Ethernet packets, etc.
Industry:Entertainment
A line using two conductors to carry the signal, neither of which is connected to ground.
Industry:Entertainment
The difference between the time it takes for the chrominance portion of the signal to pass through a system and the time it takes for the luminance portion to pass through.
The amount of distortion is expressed in units of time, typically nanoseconds.
The number is positive for delayed chrominance and negative for advanced chrominance. This distortion manifests itself in the picture as smearing or bleeding of the color particularly at the edges of objects in the picture. It may also cause poor reproduction of sharp luminance transitions.
Any signal containing a 12.5T sine-squared pulse with 3.579545 MHz modulation can be used to measure chrominance-to-luminance delay distortions. Many combination signals such as FCC Composite and NTC-7 Composite contain this pulse.
Industry:Entertainment
The difference between the gain of the chrominance components and the gain of the luminance components as they pass through the system. The amount of distortion can be expressed in IRE, percent, or dB. The number given is negative for low chrominance and positive for high chrominance. This distortion most commonly appears as attenuation or peaking of the chrominance information that shows up in the picture as incorrect color saturation. Any signal containing a 12.5T sine-squared pulse with 3.579545 MHz modulation can be used to measure chrominance-to-luminance gain distortions. Many combination signals such as FCC Composite and NTC-7 Composite contain this pulse.
Industry:Entertainment
The range of frequencies over which signal amplitude remains constant (within some limits) as it is passed through a system.
More specific definitions include:
a) The difference between the upper and lower limits of a frequency, often measured in megahertz (MHz).
b) The complete range of frequencies over which a circuit or electronic system can function with less than a 3 dB signal loss.
c) The information carrying capability of a particular television channel.
d) A measure of information capacity in the frequency domain. The greater the bandwidth of a transmission channel, the more information it can carry. e) In television, bandwidth is usually expressed in MHz.
Industry:Entertainment
This distortion is also known as crosstalk or cross-modulation. Splice is present when luminance amplitude is affect by the superimposed chrominance. The luminance change may be caused by clipping of high-amplitude chrominance peaks, quadrature distortion or crosstalk. The modulated pedestal is used to test for this distortion. Distortions can be expressed as: IRE with the pedestal level normalized to 50 IRE, as a percentage of the pedestal level, as a percentage of the measured white bar amplitude, as a percentage of 714 mV.
These definitions will yield different results under some conditions so it is very important to standardize on a single method of making intermodulation measurements. Picture effects include unwarranted brightness variations due to color saturation changes affecting the luminance.
Industry:Entertainment
Phrase sometimes used to describe techniques to carry the maximum amount of picture information within a prescribed bandwidth; also, name applied to one MIT ATV proposal that would transmit only the spatio-temporal resolution necessary for a particular scene. For example, it would transmit no more than 24 frames per second when showing a movie shot at that rate.
Industry:Entertainment
A modern magnetic particle oxide of the high energy type used in magnetic recording tape. Chromium dioxide is a highly acicular particle with the crystal structure of rutile. Tapes made of CrO2 exhibit a coercivity of 425 to 475 oersteds.
Industry:Entertainment
A reduction in the effective bandwidth of a signal, usually to facilitate recording, transmission, broadcast, display, etc. The reduction is usually accomplished through the action of an algorithm, which may involve simple lowpass filtering, more complex processing such as interleaving or quadrature modulation, or complete resampling. The term bandwidth limiting is normally applied in analog systems, although it also has a comparable meaning in digital systems.
Industry:Entertainment
