Technical Glossary
This glossary contains definitions of words in our site that you may not understand. Choose one of the searches below to find the appropriate definition.

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Displaying 20 glossary terms found.

 


PAL
Phase Alternate Line. The phase of the color carrier is alternated from line to line. It takes four full pictures for the color to horizontal phase relationship to return to the reference point. This alternation helps cancel out phase errors. For this reason the hue control is not needed on a PAL TV set. PAL, in many forms, is used in Australia, England, Scandinavia, South Africa, and Western Europe. PAL uses 625-line, 50-field composite color transmission system. The PAL system has the advantage over NTSC in preventing inaccuracies in color resolution due to phase problems.

PAL-M
Brazilian version of PAL. Broadcast standard with 525 lines and 60 fields per second.

PALplus
Enhanced PAL system which offers widescreen broadcasting and subjectively sharper images by transmitting digital "helper" signals outside the picture area. Particularly popular in Germany with limited scope in the UK.

Pan-And-Scan
The technique used for transferring widescreen anamorphic films to standard full screen 1.33:1 aspect ratio video, so as to avoid black bars at the top and bottom of a full screen 1.33:1 display screen. Since the format cannot show the entire picture width, the transfer must continually move or pan from one part of the picture to another in order to show all the on screen action. Frequently misused to describe full frame, non-widescreen anamorphic, spherical flat photography without top and bottom black bars to properly frame the intended aspect ratio composition.

Panning
Originally a motion picture camera operator term often used to describe the movement of sounds and images from one location to another.

Parallel Surfaces
A surface that is lying or moving in the same direction but is always the same distance apart.

Parental Lockout
By punching in a special code (that the parent devises), one can lockout their children (or anyone for that matter) to specific channels on the television. One can also disable the set from being used for a specified time of day or period of hours, which is designed primarily to help parents manage their childrenís viewing time. Child lockout places parental control into the TV. See Channel Block

Partial
One of a group of frequencies, not necessarily harmonically related to the fundamental, which appear in a complex tone. Bells, xylophone blocks, and many other percussion instruments produce harmonically unrelated partials.

Passive Absorber
A sound absorber that dissipates sound energy as heat.

Passive Crossover
A crossover network made up of elementary circuit components (capacitors, resistors, inductors), and is not powered. They are used most commonly in loudspeaker systems.

Passive Equalizer
An equalizer which does not contain amplification in the equalization circuit. As a result this type of equalizer suffers an inherent "insertion loss."

Passive Graphics
A computer graphics operation that transpires automatically and without operator intervention.

Passive Radiator
An undriven loudspeaker cone used to extend low-frequency sound.

Passive Subwoofer
A subwoofer which does not have onboard amplification and an active crossover. They work only with systems equipped with dedicated power amplifiers and surround sound processors with a crossover, such those which are THX certified.

Path Length Difference
The difference in time/ distance of source energy from reflected energy.

PC
Personal Computer or Projector Control.

PCB
Printed Circuit Board.

PCM
Pulse Code Modulation. A form of digital binary recording that represents an audio signal as a series of digital samples or electrical pulses. See Digital Recording.

Peak
The highest or lowest level of signal strength, as determined by the height of the signalís waveform.

Period
The length of time (measured in seconds) it takes for a wave to complete a cycle.