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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.
During video recording, the video signal is usually accompanied by an audio signal. Sometimes, during video editing, it is often necessary to separate the audio from the video signal. Audio-follow-video mixers allow accompanying audio to "follow" the video when switching video sources or not.
Industry:Entertainment
Synchronization. A term used in electronics to describe the precise alignment of two signals or functions. In video, sync is an essential element for maintaining the proper clocking of video signals. The sync signal is used by a monitor to know where and when to draw the on-screen video image. The horizontal sync signal is a short pulse generated at the beginning of each video line which tells the video monitor when to draw each new line. The vertical sync signal is a short pulse generated at the beginning of each video frame which tells the video monitor when to start a new field. Sync signals reside in the part of a video signal in which no visual picture information is transmitted. During this blanking period or horizontal or vertical interval, the electronic beam is blanked and retraces back to the other side of the screen to start a new line or new field. Since this is done during the blanking period, it is invisible to the viewer. Both horizontal and vertical sync are required in order to maintain a stable on-screen picture. Many video processing devices provide sync restoration and correction circuitry. Sometimes, a TBC is required to recover or restore sync.
Industry:Entertainment
a) Circuitry used to ensure that output signals are maintained at constant levels in the face of widely varying input signal levels. AGC is typically used to maintain a constant video luminance level by boosting weak (low light) picture signals electronically. Some equipment includes gain controls that are switchable between automatic and manual control.
b) Electronic circuitry that compensates for either audio or video input level changes by boosting or lowering incoming signals to match a preset level. Using AGC, changing input levels can output at a single constant setting.
c) A feature on most video cameras and camcorders that, when engaged, boosts the signal to its optimum output level. Automatic gain control (AGC) is available for video, and less frequently audio use.
Industry:Entertainment
When a particular scene is repeated and photographed more than once in an effort to get a perfect recording of some special action, each photographic record of the scene or of a repetition of the scene is known as a "take." For example, the seventh scene of a particular sequence might be photographed three times, and the resulting records would be called: Scene 7, Take l; Scene 7, Take 2; and Scene 7, Take 3.
Industry:Entertainment
Circuitry used to automatically adjust the audio recording level to compensate for variations in input volume.
Some equipment includes level controls that are switchable between automatic and manual control.
Industry:Entertainment
Something other that what it appears to be. Stairsteps on what should be a smooth diagonal line are an example of spatial alias.
Wagon wheels appearing to move backwards are an example of temporal alias. Aliases are caused by sampling and can be reduced or eliminated by pre-filtering, which can appear to be a blurring effect. Defects in the picture typically caused by insufficient sampling (violation of the Nyquist sampling rate) in the analog-to-digital conversion process or poor filtering of digital video. Defects are typically seen as jaggies on diagonal lines and twinkling or brightening in picture detail. Examples are: Temporal Aliasing – such as rotating wagon wheel spokes appearing to rotate in the reverse direction. Raster Scan Aliasing – such as sparkling or pulsing effects in sharp horizontal lines. Stair-Stepping – stepped or jagged edges in diagonal lines or the diagonal parts of a letter.
Industry:Entertainment
Telecine is a term used to describe a device used to convert film to video. In advanced telecine machines, the movie film is digitally sampled and converted to video, frame by frame in real-time. Frame rate is the biggest problem encountered in film-to-video conversion. Movie film has a frame rate of 18, 24 or 30 fps (frames per second) contrasting with the 30 and 25 fps video frame rates of NTSC and PAL respectively.
Industry:Entertainment
a) A continuous electrical signal that carries information in the form of variable physical values, such as amplitude or frequency modulation.
b) A signal which moves through a continuous range of settings or levels.
c) An adjective describing any signal that varies continuously as opposed to a digital signal that contains discrete levels representing the binary digits 0 and 1.
d) A signal that is an analogy of a physical process and is continuously variable, rather than discrete. See also Digitization.
Industry:Entertainment
A general term for a meeting not held in person. Usually refers to a multi-party telephone call, set up by the phone company or private source, which enables more than two callers to participate in a conversation. The growing use of video allows participants at remote locations to see, hear, and participate in proceedings, or share visual data ("video conference").
Industry:Entertainment
