# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

0 LuxShot-Technique allowing pictures to be shot without visible light. The camera is switched to its infrared sensitivity mode and infrared lighting (built-in to Sony IR sensitive cameras) is used to illuminate the scene. As the picture is only infrared, no significant color information is displayed. The picture looks slightly greenish, like an image intensifier picture. NOTE: In 0 LuxShot mode, the iris remains in a fully open position, and the high-speed shutter feature does not function.

3:2 Pulldown- The method used to convert 24 frames per second film into 30 frames per second video. Every other frame is held for 3 video fields resulting in a sequence of 3 fields, 2 fields, 3 fields, 2 fields, etc. (See Fields, Frames)

4:4:4 / 4:2:2 / 4:1:1-Indicates the sampling applied to the Y/R-Y/B-Y components of an analog video signal when it is converted into a digital signal. The three numbers indicate the ratio of the sampling rates applied to the individual signals. 4:4:4 indicates that the same sampling rate has been applied to all three signals, 4:2:2 means that the sampling rate of the R-Y and B-Y color difference signals is half that of the luminance signal Y, while 4:1:1 indicates that the sampling rate is one quarter that of the Y signal.

16x9- The wide screen format for television that uses the aspect ratios of 16 units wide by 9 units high.

A -back to top

AAC- Advanced Audio Coding (MPEG-2).

ACATS- FCC Advisory Committee on Advanced Television Service.

Access Unit- A coded representation of a presentation unit. For audio, an access unit is the coded representation of an audio frame; for video, an access unit is the coded representation of a picture.

ACK- Acknowledge signal (type II and type II handshake).

Active Picture Area- The visual part of a TV signal that has the actual picture in it, without the technical information or other data like sync, etc.

A/D or ADC- Analog-to-Digital Converter. A circuit that converts an analog signal, having a continuously varying amplitude, to a digitally quantized representation using binary output signals.

ADPCM- Adaptive Differential Pulse Code Modulation.

ADSI- Analog Display Services Interface (type III protocol). A subscriber feature than enables transfers and display of larger amounts of data.

ADSL- Asymmetrical Digital Subscriber Line. A twisted-pair-based distribution system providing transmission rates up to 6.3 Mb/s.

ADTV- Advanced Digital Television. An HDTV system proposed by the Advanced Television Research Consortium, consisting (in 1992) of David Sarnoff Research Center, North American Philips, Thomson Consumer Electronics, NBC, and Compression Labs, Inc.

AE- (Auto Exposure) Combined use of AGC and iris motor control allows shooting in a broad range of lighting conditions. AGC amplifies the video signal in low light conditions, iris reduces it in high light conditions. Motor iris control can be replaced by the CCD IRIS control.

AES/EBU- Audio Engineering Society / European Broadcast Union. these organizations defined the audio standard for CD's D1 and more.

AF- Alternative Frequencies. This list is compiled in memory within the receiver of nearby broadcast stations that carry the same program. This is to allow the motorist who is traveling away from his local station to automatically switch to the next geographically located station for continuation of the same program (such as NPR).

AF- (Autofocus) Available in cameras equipped with motorized focus, this feature provides automatic adjustment of the focus. AF operates by varying the focus to maximize the high frequency content of the central area of the picture by reference to high luminance and strong contrast elements. In some cameras, AF can be set to High or Low sensitivity modes. AF mode is not recommended for continuous 24-hour operation. See also One-push AF, Interval AF, Zoom triggered AF.

AFC- Automatic Frequency Control.

AGC-(Automatic Gain Control) Circuitry that automatically adjusts the electronic amplification of the video signal to compensate for varying levels of scene illumination.

Aliasing- Image artifacts in captured images caused by significant energy in the scene at frequencies higher than the Nyquist limit of the sensor. In single-chip color cameras, aliasing can produce unexpected color patterns in highly detailed monochrome objects. The defects in a video picture. They are normally caused by sampling rates that are either too low, or had poor filtering. Aliasing appears as stair steps in diagonal lines on the screen. Interference phenomenon which occurs when a sampled signal contains frequencies that are higher than half the sampling frequency. A CCD samples the picture spatially. An optical low-pass filter is used to avoid aliasing, especially in color applications.

Anti-aliasing- The process of removing aliasing, .

Analog- A signal that has variance over a range of amplitudes. This is different from digital, where digital uses binary to express values.

Aperture Correction- Camera signal processing function which adjusts the enhancement of edges of objects in a picture.

Artifact- A visual effect caused by an error or limitation in the system.

ASIC- Application-specific integrated circuit. An IC designed for a custom requirement, frequently implemented in a gate array or field programmable array.

ASK- Amplitude Shift Keying. A digital amplitude modulation method.

Aspect Ratio- The ratio of width over height of an image, 4:3 for a standard TV image, 16:9 for wide screen.

Asynchronous Transmission Mode- IEEE 1394 data transmission mode without a guaranteed data delivery time. Used in IEEE 1394 cameras for control functions and reports.

ATC- Adaptive Transform Coding.

ATM- 1. Asynchronous Time Multiplex.
2. Asynchronous Transfer Mode.

ATRAC- Adaptive Transform Acoustic Coding (Sony).

ATV- Advanced Television. The term is often used interchangeably with HDTV.

ATW -(Auto Tracking White balance) In ATW mode, white balance is continuously being adjusted according to the color temperature of the scene illumination.

Audio Bandwidth- The signal range from 20 Hz to 20 kHz, according to the standard specification, although there is some evidence of acoustic perception outside that bandwidth in exceptional individuals, particularly young children.

AWGN- Additive White Gaussian Noise.

B -back to top

Backlight Compensation- Special compensation option in AE (Auto Exposure) mode. When the background is too bright and/or when the subject is too dark, backlight compensation modifies the action of Auto Exposure to make the subject appear clearer.

Bandwidth- The amount of data that can be processed or transfered at a given point in time.

Bayonet Mount- Type of camera mount in which there is 38 mm or 48 mm clearance between the lens rear mounting surface and the camera’s CCD. – phenomenon that is particularly obvious in extreme high light

BBC- British Broadcasting Corporation.

BC- Backward Compatibility.

BCH- Bose-Chaudhuri-Hocquenghem.

BD- Block Difference.

Betacam- An analog videotape format created by Sony.

Bit Rate- The rate at which the compressed bitstream is delivered from the channel to the input of a decoder. This is typically defined in bits per second. This is the amount of data communicated over a medium in a given period of time.

Black Stretch / Black Compress Control- A function of Digital Signal Processing technology that enables the contrast of the black area of an image to be variable adjusted. The black stretch function emphasizes contrast in the dark areas while black compress enhances or deepens darkness.

BMA- Block Matching Algorithm.

bpp- Bits per pixel (picture element or pel).

Brightness- The aspect of perception that changes as the intensity of a patch of light is varied.

BS- Base Station.

Byte Aligned- A bit in a coded bitstream is byte-aligned if its position is a multiple of 8 bits from the first bit in the stream.

C -back to top

C/N- Carrier/Noise ratio.

CA- Conditional Access. A mechanism by which the user access to service components can be restricted.

CAS- CPE alerting signal (type II and type III handshake).

CAT- Conditional Access Table, provides the association between one or more conditional access systems, their entitlement management message streams, and any special parameters associated with them.

CAT 5- Category 5 10/100 computer network cable. It consists of 4 twisted pair wires inside shielding. The twist in the cable enhances insulation against outside electrical interference. The color setup for each cable is as follows: Pair One (white/ orange and orange); Pair Two (white/ green, green); Pair Three (white/ blue, blue); Pair Four (white/ brown, brown).

CATV- Community Antenna Television.

CBP- Coded Block Pattern.

CBPY- Coded Block Pattern for luminance.

CBR- Constant Bit Rate. An operation in which the bit rate is constant from start to finish of the compressed bitstream.

CCD- Charge-Coupled Device. A type of silicon integrated circuit used to convert light into an electronic signal.Semiconductor device made of a matrix (or lines) of individual photosensitive elements, called pixels. The optics focus the scene onto the matrix and each pixel accumulates an electric charge proportional to the local intensity of received light and to the integration time. At read out time, all charges are transferred at the same time to an output matrix protected from light, where a sequential reading may take place while a new picture starts integrating. The output matrix size is half that of the sensitive matrix size for interlaced mode CCDs, and the same size for progressive scan CCDs.

CCDC- Channel Compatible DigiCipher. An HDTV system proposed by the American Television Alliance, consisting of General Instruments and Massachusetts Institute of Technology.

CCD IRIS- Special operating mode of the electronic shutter of a CCD camera. The shutter timing is automatically adjusted to maintain the same video output level, irrespective of the scene illumination. Can only reduce the camera sensitivity. Allows the use of a fixed iris lens under variable lighting conditions. Often combined with AGC.

CCETT- Centre Commun D'Etudes de Telecommunications et de Telediffusion.

CCIR- B/W video standard with 625 lines / frame, 2 interlaced fields / frame, 25 frames / second. Monochrome version of PAL.

CCITT- International Telegraph and Telephone Consultative Committee. A standardization body for telecommunications.

CCU-(Camera Control Unit) The CCU provides a means of controlling a remote camera. So that the remote camera can be as small and light as possible, the CCU also includes all electronic circuits that do not have to be fitted inside the remote head, these are typically signal processing circuitry, input/output interfaces and power supply.

CD- Compact Disc.

CDMA- Code-division multiple access, based on spread-spectrum code assignments.

CDS- Correlated Double Sampling, a circuit commonly used to process the output signal from a CCD image sensor in order to reduce low-frequency noise components.

CEBus- Consumer Electronics Bus. A multimedia distribution system in the home.

CELP- Code-Excited Linear Predictive coding.

CFA- Color Filter Array. A mosaic or stripe layer of colored transmissive filters fabricated on top of an imager in order to obtain a color image from a single-image sensor.

Chrominance- Color part of the composite video signal. Also called C. Separately transmitted in Y/C (S-video). It is the combination of the two color difference signals (U or R-Y) and (V or B-Y) modulated on to a subcarrier. See also YUV.

CHU-(Camera Head Unit) In a remote head camera system, the CHU is a small unit that only includes the sensor, its optical interface, the cable coupling to a CCU and the minimum amount of electronic circuitry.

CIDCW- Call Identification Delivery on Call Waiting (type II). A subscriber feature that allows for the display of the time, date, number, and other information about the caller to the called party while the called party is off-hook.

CIF- 1. Common Intermediate Format.
2. Common Interleaved Frame, the serial digital output from the main service multiplexer, which is contained in the main service channel part of the transmission frame. It is common to all transmission modes and contains 55,296 bits (i.e. 864 Cus).

CISC- Complex Instruction Set Computer. A standard computing approach taken by Intel and MC68000 microprocessors.

CLASS- Custom Local-Area Signaling Service. A set of services and enhancements provided to customers that may include CND, CNAM, message waiting, and other features.

CLID- Calling Line Identification Delivery (type I). A subscriber feature that allows for the on-hook display of the time, date, number, and other information about the caller to the called party.

CMA- Constant Modulus Algorithm for updating tap-weight coefficients in blind equalization.

CMFSK- Coherent Multilevel Frequency Shift Keying.

C-Mount- Type of camera mount in which there is 17.526 mm clearance between the lens rear mounting surface and the camera’s CCD.

CNAM- Calling Name delivery. A subscriber feature that allows for the display of the time, date, number, and name of the caller to the called party.

CND- Calling Number Delivery. A subscriber feature that allows for the display of the time, date, number, and other possible information about the caller to the called party.

CNET- Centre National d'Etudes de Telecommunications.

CO- Central Office. A main telephone office, usually within a few miles of a subscriber, that houses switching gear. Commonly capable of handling about 10,000 subscribers.

Coding- Also called compression or bit rate reduction, the process of taking a signal and reducing the number of bits, energy, time, or bandwidth necessary for its transmission. In the context of this chapter, coding refers specifically to bit rate reduction of a digitally captured or encoded signal.

Color Pixel Reconstruction- An algorithm that creates a fully populated color image record from the output of a CFA-type sensor by interpolating values for each color at each pixel location.

Component Video- The type of signal that keeps luminance and chrominance separate. This improves the overall quality of the picture.

Composite sync- Combination of the HD and VD in one signal. Commonly used as a synchronizing or genlock signal in B/W systems.

Composite Video- The type of signal that combines luminance and chrominance signals to make for easier broadcasting. This is where modern NTSC, PAL and other formats originated as industry standards.

Compression Ratio- The ratio of the amount of data in the original piece of data, compared to the amount after compression of some form.

Contrast- A measure of the difference in intensity between two adjacent patches of light.

Convolution Coding- The coding procedure that generates redundancy in the transmitted data stream in order to provide ruggedness against transmission distortions.

CPE- Customer Premises Equipment, a term used to define a class of consumer devices found in the hope that connect to a public network. Examples include a set-top box, telephone, satellite receiver, personal computer with a modem, answering machines, and fax machines.

CPM- Continuous-Phase Modulation.

CPT- Call Progress Tones, DTMF tones sent while off-hook to signal-enhanced features.

CRC- Cyclic Redundancy Check, verifies the correctness of data.

CRT- Cathode Ray Tube. The tube found in most non-flat panel televisions. Its is an evacuated tube where by use of magnetics and an electron gun projects a stream of electrons onto a phosphorus screen in lines to create an image.

CSO- Composite Second Order. A clustering of second-order frequency beats at 1.25 MHz above the visual carriers in cable systems.

CSPS- Constraint System Parameters Stream. An MPEG-2 program stream that conforms to the founds specified in the MPEG-2 system layer specification.

CT- Clock-Time and Date, Coordinated Universal Time (UTC) code can be used to set the clock to the exact time as displayed on the receiver.

CT2- Cordless Telephone-2. A second generation cordless telephone system introduced in Great Britain in 1989.

CTB- Composite Triple Beat. A clustering of third-order frequency beats around the visual carriers in cable systems.

D -back to top

DAA- Data Access Arrangement. A CPE interface to network, complying with title 47, part 68 of the Code of Federal Regulations.

DAB- Digital Audio Broadcasting.

DAT- Digital Audio Tape.

DAVIC- Digital Audio-Visual Council. A nonprofit association whose purpose is to identify, select, augment, develop, and obtain the endorsement of formal standards bodies of specifications of interfaces, protocols, and architectures of digital audiovisual applications and services.

DBD- Displaced Block Difference.

DBS- Direct Broadcast Satellite. A digital system for sending/receiving an MPEG-2 transport stream providing audio/video and data services from a stationary satellite to a small receiving antenna.

DCD- Digital Compact Disc.

DCME- Digital Circuit Multiplex Equipment.

DCS 1800- Digital Communication System-1800, which is an extension of the Global System for Mobile Communications standard in the 1800-MHz band for personal communication networks.

DCT- Discrete Cosine Transform.

DDCR- Decision-Directed Carrier Recovery. A carrier recovery scheme that uses the decisions feedback from the receiver bit or symbol decision detection circuit.

DECT- Digital European Cordless Telephone. A cordless telephone standard developed by the European Telecommunications Standards Institute in 1992.

Degauss- To erase information from a magnetic disk or tape.

Depth of Field- Distance between the nearest and farthest points in a scene that are in focus as viewed by a particular lens. Affected by choice of lens focal length and iris aperture. Increases with both decreasing lens focal length and decreasing iris aperture.The difference between the maximum and minimum distances from a camera to objects in a scene that can be captured in acceptably sharp focus.

DFE- Decision Feedback Equalizer. A nonlinear equalizer consisting of a feed-forward equalization filter and a feedback equalization filter.

Digital- A form of data where all values are represented in binary.

Digital Camera- An electronic camera that captures images using a solid-state image sensor, and then outputs a digital signal representing the images or records the images on a digital storage medium.

Digital Glitch- This is the popping or clicking from a bad read off a Mini DV tape. It can sometimes also be seen on the screen as square spots on the screen where picture is lost. This is often caused by a bad tape, or deck, or by switching between dry and wet Mini DV tapes without cleaning the deck heads beforehand.

Digital Betcam- A digital videotape format that uses CCIR 601 standard in order to record 4:2:2 component video in a compressed format onto tape.

Digitizing- taking analog data and converting it into digital data. An example of this is taking an analog VHS tape, and digitizing its footage onto a non-linear editing system on a computer.

DMC- Discrete memoryless channel, which is specified by the transition probabilities of input and output symbols.

DMT- Discrete multitone. A multicarrier modulation scheme.

DN- Directory Number.

Donpisha- CCD sensor shuttering technology for asynchronous shooting of fast moving objects without a time delay.

DPCM- Differential Pulse Code Modulation.

DSC-HDTV- Digital Spectrum-Compatible HDTV. An HDTV system proposed by Zenith Electronics and AT&T in 1992.

DSM- 1. Digital Storage Medium. A digital storage or transmission device or system.
2. Direct Sequence Modulation. A spread spectrum modulation scheme that directly modulates the information-bearing data with a spreading code sequence.

DSM CC- Digital Storage Medium Command and Control. A protocol intended to provide the basic control functions and operations specific to managing an MPEG-2 system bitstream on digital storage media.

DSP- Digital Signal Processor. An architecture, based on the Harvard machine, that uses separate data and instruction buses as well as certain instructions optimized for signal processing, such as multiply/accumulate. Inside a camera, sensor signals must be processed in several steps before they can be displayed / transmitted. Typical processing steps are amplification, gamma correction, black level correction, highlight compression/clipping, edge enhancement, color processing, color balance, color correction, output signal encoding. Picture quality is highly dependent on the accuracy and the stability of these processes. In DSP technology, the sensor signal is converted to digital form after initial amplification, and all processing is achieved digitally, ensuring high quality and no drift. Output signals remain in digital form or are converted back to analog depending on the camera output mode.

DTMF- Dual-tone multifrequency, a tone-dialing system based on outputting two non-harmonic-related frequencies simultaneously to identify the number dialed or signal call progress. Eight frequencies have been assigned to the four rows and four columns of a typical keypad.

DTS- Decoding Time Stamp. A field that may be present in a PES packet header that indicates the time that an access unit is decoded in the system target decoder.

DTTB- Digital Television Terrestrial Broadcasting.

DVB- Digital Video Broadcasting.

DVD- Digital Versatile Disk. Digital Versatile Disc. A high-density CD-ROM technology that provides capacity for full-length MPEG-2 movies as well as data and audio storage and playback. (Also called Digital Video Disc.)

DynaLatitude Process- A unique feature function available when using Digital Signal Processing (DSP) technology. It manages the contrast of each pixel according to a histogram of video signal level distribution in order to utilize the limited dynamic range of the video signal standard. This function is used in the DXC-390/P camera.

Dynamic Contrast Control Plus (DCC+)- A function of Digital Signal Processing (DSP) technology that virtually eliminates hue factor distortion – phenomenon that is particularly obvious in extreme high light conditions. The DCC+ function manages video signal data at three levels – brightness, hue and saturation that results in reproduced images with suitable knee correction while virtually eliminating hue factor distortion. This function is used in the DXC-390/P camera.

E -back to top

EBU -European Broadcast Union.

ECM -Entitlement Control Message. Private conditional access information that specifies authorization levels or the services of specific decoders.

Edge Enhancement -A signal-processing operation that accentuates edge details within an image to increase the apparent sharpness. Such operations may also be called aperture correction, sharpening, or peaking.

E-Donpisha- Enhanced asynchronous shutter. Available with external and internal synchronization modes. The camera CCD starts to accumulate electrons on receipt of an external trigger pulse. Shutter speed is selected by a switch or menu setting.

E-Donpisha - II- Asynchronous shutter mode. Available in external sync mode only. Timing of accumulation and shutter speed are controlled by the external trigger signal. Shutter speed is controlled by the width of the pulse and VD controls the timing for image output.

EIA - Electronic Industries Association. A standard-setting body for consumer electronics.B/W video standard with 525 lines / frame, 2 interlaced fields / frame, 30 frames / second. Monochrome version of NTSC video signal. Also referred to as RS-170.

EIA-NRSC -Electronic Industries Association -- National Radio Systems Committee.

Electronic shutter- CCD camera operating mode where the integration time can be shortened without any mechanical device. Used for blur reduction when capturing fast moving objects, and for camera sensitivity reduction in high levels of scene illumination.

Ensemble - The transmitted signal comprising a set of regularly and closely spaced orthogonal carriers. The ensemble is the entity that is received and processed. In general, it contains program and data services.

EOB -End of Block.

EON -Enhanced Other-Networks Information. This feature can be used to update the information stored in a receiver about program services other than the one being received. Alternative frequencies, the Program Stream (PS) name, traffic programs, announcement, identifications, and other information can be used to provide linkage to such other programs.

ES -Elementary Stream. A generic term for one of the coded video, coded audio, and other coded bit data in Packet Elementary Stream (PES) packets.

Evaluated tape- Any tape format that has been recorded to once, then inspected, erased and cleaned for reuse.

EWS -Emergency Warning System. This is intended to be used for the coding of audio and digital emergency and alerting messages. Such codes can be coordinated with national emergency and disaster agencies.

Exposure Determination -A method for setting the appropriate lens aperture and exposure time for a scene to be captured.

Exwave HAD technology-Technology with a nearly gapless OCL (On-chip-lens) located over each pixel of the CCD resulting in more than twice the sensitivity and 1/50 the smear compared to Hyper HAD technology.

F -back to top

F Stop, F Number-Calibrated measure of lens iris aperture. Common F stops are F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, F22. The higher the number, the smaller the iris aperture and the less light falling on the imager.

FDCT- Forward DCT(Discrete Cosine Transform).

FDMA- Frequency-Division Multiple Access, based on frequency assignments.

FEC- Forward Error Correction.

FFT- Fast Fourier Transform.

FhG- Fraunhofer-Gesellschaft.

FHM- Frequency-Hopping Modulation. A spread-spectrum modulation scheme that is used to nonlinearly modulate a train of pulses with a sequence of pseudorandom frequency shifts.

FIB- Fast Information Block. A data burst of 256 bits. The sequence of FIBs is carried by the fast information channel. The structure of the FIB is common to all transmission modes.

FIC- Fast Information Channel. A part of the transmission frame (comprising the fast information blocks) that contains the multiplex configuration information, along with optional service information and data service components.

Field- Half of a TV picture consisting of only the odd or only the even lines. NTSC/EIA features 60 fields of 262.5 lines / second. PAL/CCIR features 50 fields of 312.5 lines / second. Odd / even field pairs recombine on screen as frames due to picture tube and human eye memory. Field / frame integration: Two different pixel readout techniques in CCDs designed for interlaced output. Refers to the total integration time, field duration (16.6 ms NTSC/EIA or 20 ms PAL/CCIR) or frame duration (33.3 ms NTSC/EIA or 40 ms PAL/CCIR). Both modes give the same sensitivity. In field integration, pixels of two adjacent lines are read out together as one. The full CCD is read every field, achieving higher picture refresh rate but lower vertical resolution. Mostly used in current applications to achieve optimum capture of movement. Adjacent lines are combined differently for odd (1+2, 3+4, . . .) and even field (2+3, 4+5, . . .) outputs. In frame integration, pixels are read out separately. The complete CCD is read after two fields. Full vertical resolution is achieved. Progressive scan CCDs operate only in frame integration.

FIR- Finite Impulse Response. Commonly referring to an implementation structure of a filter.

FLC- Fixed-Length Coding.

Focal length- Distance between the optical center of a lens and the image focal point. Fixes the magnification and the angle of view of a lens. Vari-focal and zoom lenses have a variable focal length.

FPLL- Frequency- and Phase-Locked Loop.

Frame- One complete TV picture consisting of two sequential interlaced scanned fields. NTSC/EIA has 30 frames of 525 lines per second. PAL/CCIR has 25 frames of 625 lines per second.

FSE- Fractionally Spaced Equalizer, whose tap spacing is a fraction of a data symbol duration.

FSK- Frequency-Shift Keying. FSK uses the data stream to modulate a carrier frequency.

Full-Frame Imager- A type of image sensor consisting of a single light-sensitive array of photoelements that also store the image during the sensor readout period.

G -back to top

GA- Grand Alliance. A U.S. HDTV consortium consisting of General Instruments, Zenith Electronics, AT&T, David Sarnoff Research Center, Thomson Consumer Electronics, North Philips Electronics, and Massachusetts Institute of Technology.

Gain- The electronic amplification factor of a signal.

Gamma Correction- A signal-processing operation that changes the relative signal levels in order to adjust the image tone reproduction, typically to correct for the nonlinear (nonunity gamma) light output-versus-signal input characteristic of the display. The relationship between the camera light input and the camera output signal level, called the optoelectronic conversion function (OCEF), provides the camera's gamma correction curve shape.
Correction law introduced in the camera output signal to compensate for the non-linearity of the CRT (Cathode Ray Tube) in video monitors. A typical gamma value is 0.45, which results in the brightness component of the CRT picture appearing to be linear.

GBSC- GOB Start Code.

Genlock- Circuitry that synchronizes one video signal to another video signal. There are three types of genlock: V-lock, HV-lock and full color.
• V-lock is useful when simply switching from one B/W color source to another
• HV-lock is used for full synchronization of B/W cameras, and requires a HD + VD input, composite sync input or composite VS video signal input. In the case of color cameras, this type of synchronization can be used when cutting between pictures, but not for mixing between them.
• Full color genlock is used when pictures have to be mixed without color degradation. It needs VBS composite video input.

GMSK- Gaussian Minimum Shift Keying. A minimum shift keying with Gaussian frequency pulse shaping.

GOB - Group of Blocks.

GPS- Global Positioning System. A satellite ranging system based on direct sequence spread spectrum for mobile users to determine their location.

GSM- Global System for Mobile Communications. A second-generation cellular system standard set by the European Technical Standards Institute in 1990

H -back to top

HAC- Host Adapter Card.

HAD (Hole Accumulated Diode)- CCD technology with improved performance in spectral response, vertical smear and sensitivity. The HAD sensor also introduced a higher pixel count and electronic shuttering capability.

HAS- Human Auditory System. The outer, middle, and inner ear along with the parts of the central nervous system that are involved in hearing, speech understanding, spatial localization, and other auditory functions.

HD (Horizontal Drive)- Signal used to synchronize the line scan rate of the camera to an external source. Mostly used in B/W applications together with VD.

HD-DIVINE- A Scandinavian digital terrestrial HDTV project proposed in 1991.

HDSL- High-speed Digital Subscriber Line, providing T1 rate services.

HDTV- High-Definition Television. An advanced digital television providing high resolution.

HFC- Hybrid fiber and coaxial network.

Hi-UD Glass- A canon technology that has a high refractive index and very low dispersion to correct chromatic aberrations with out the heavy weight of conventional multi lens designs to solve chromatic aberrations.

High rate scanning- Capability of a camera to output less than its maximum number of horizontal lines, but at a higher rate. Unlike partial scanning, the lines output in high rate scanning are symmetrical about the optical sensor center. This means that there is normally no need to re-aim the camera when changing from normal to high rate scanning.

Horizontal Resolution- Number of equally spaced vertical black-to-white or white-to-black transitions that the camera is able to reproduce, divided by the aspect ratio (usually 4:3) to make a comparison between horizontal and vertical resolution easier. Usually expressed as TV lines per picture height. Indicates the amount of horizontal details that can be perceived. Horizontal resolution is limited by the number of pixels in one line and by the type of color filter used, if any.

HVS- Human Visual System. The eye, optic nerve, visual cortex, and other parts of the central nervous system involved in seeing and interpreting images.

Hybrid Photography- A type of digital photography system in which original scenes are captured using traditional silver-halide-based photography, and the resulting film or prints are scanned to provide digital images that may be displayed, manipulated, transmitted, etc.

Hyper HAD- A derivative of the HAD sensor that incorporates microscopic lenses mounted over each sensing pixel. Hyper HAD sensors have no perceptible smear and are nearly twice as sensitive as HAD sensors.

Hyperfocal Distance- The focus distance of a camera lens that offers the greatest depth of field. When a camera is focused at the hyperfocal distance, all objects from half the hyperfocal distance to infinity are within the camera's depth of field.

I -back to top

I -In-phase Component.

ICI- Intercarrier Interference, associated with multicarrier modulation systems.

ICR -(IR Cut Removable) This function is useful in low light environments. With the IR cut filter removed, the sensitivity of the camera to IR illumination is increased.

IDCT- Inverse DCT.

IEEE -Institute of Electrical and Electronics Engineers.

IEEE 1394- This is the industry standard set out for Fire Wire by the Institute of Electrical and Electronics Engineers. A digital networked serial interface for high-speed data transmission. Available speeds are 200 and 400 Mb/s, and 800 Mb/s speed is planned in the near future. IEEE 1394 is an ideal interface between a computer and audio/video products because of its ability to transfer a real-time data stream at low cost, with high reliability and ease of use.

IEEE 802.3- This is the industry standard set out for CAT 5 computer networks by the Institute of Electrical and Electronics Engineers.

IH- In-House Application. Data used by the station for internal use. For example, IH could be used as a remote switch to turn on/off a remote transmitter site via the studio-to-transmitter link.

IM- Intermodulation, referring to distortions generated by nonlinear devices in a system.

Image Compression -A process that alters the way image data are encoded in order to reduce the average size of an image file.

Image Data Format -A specification for storing image data and related information in a digital file. One example is TIFF, tag image file format, which can be used to store various types of monochrome or color bit-mapped images.

Imaging Chain -A flow diagram that indicates all of the components used to produce a final image in a digital photography system.

Interlace- This technique is used in low bandwidth situations where there is not enough bandwidth across a medium to make an image that won't flicker when viewed. To solve this problem interlacing is used where the picture is split into two separate fields and then sending all of the odd numbered lines to one field and all the evens to another.

Interlaced Scanning - Scanning method in which half of the lines are scanned in one field (odd-numbered lines), and the other half are scanned in the next field (even-numbered lines). Thus adjacent lines of a complete picture (one frame) belong to successive fields. Interlaced scanning doubles the screen refresh rate as seen by the viewer and reduces flicker. At screen refresh rates significantly higher than the 25/30 frames/second used in TV systems, interlaced scanning may not be necessary.

Interline Sensor -A type of image sensor consisting of a two-dimensional array containing light-sensitive photoelements adjacent to light-shielded vertical storage registers.

Interline Transfer- In IT CCD technology, the charges on exposed pixels are transferred to light-shielded vertical readout zones embedded in the sensitive area. IT devices are simpler to manufacture and are therefore less costly than FT or FIT devices. Mostly used in industrial and consumer cameras.

Interval AF- AF (Auto Focus) mode is periodically switched ON, then OFF (fixed focus). The duration of the on and off intervals is separately adjustable.

Iris- An adjustable sized aperture in a camera lens that controls the amount of light reaching the imager. Compensates for changing lighting conditions. Iris control may be either manual or automatic, depending on the application and the type of camera. When iris is fixed, a variable electronic shutter can be used instead (CCD Iris).

Irrelevancy- The part of a signal that is not perceptible to the human user under the normal circumstances of use. In other words, irrelevancy is the part of the signal that may be removed at the encoder, and removed at the decoder, with no loss of content.

IRT- Institut fur Rundfunktechnik, Munchen (FRG).

IS- International Standard.

IS-54- Interim Standard-54. A dual mode standard for U.S. digital cellular system and Advance Mobile Phone Service based on time-division multiple access, set by EIA/TIA in 1990.

IS-95 -Interim Standard-95. An air interface standard for U.S. code-division multiple access and Advance Mobile Phone Service dual-mode operation for mobile and cellular users.

ISDN -Integrated Services Digital Network. A communications network intended to carry digitized voice, data, and video services multiplexed onto the public network with rates up to 64 kb/s.

ISI- Intersymbol Interface. The additive contribution (interference) to a received sample from transmitted symbols other than the symbol to be transmitted.

ISM Bands-Industrial, Scientific, and Medical frequency bands 902-928 MHz, 2.4-2.4835 GHz, and 5.725-5.85 GHz.

ISO -International Organization of Standardization.

Isochronous transmission mode- IEEE 1394 data transmission mode featuring guaranteed transmission timing and bandwidth. Appropriate for just-in-time transmission of video and audio and computer data.

ITU- International Telecommunication Union. An intergovernmental organization responsible for setting global standards.

ITU-R -International Telecommunications Union-Radio Standardization Sector.

ITU-T- International Telecommunications Union-Telecommunications Standardization Sector.

J -back to top

JDC- Japanese Digital Cellular

JND- Just Noticeable Difference. The level at which an observer can begin to distinguish between an original signal and a noisy/corrupted/distorted signal. The JND is sometimes referred to as a threshold or perceptible threshold.

JPEG- Joint Photographic Experts Group

K -back to top

KB/S- Kilobits Per Second.

KLT- Karhunen-Loeve Transform.

L -back to top

LE- Linear Equalizer. A linear filter that is used to reduce intersymbol interference.

Letterbox- Placing a wide screen image on a conventional TV by putting black bars over the top and bottom of the screen.

LF- Loop Filter.

LFE- Low-Frequency Enhancement.

LMS- Least Mean Square. An algorithm for adaptively adjusting the tap coefficients of an equalizer based on the use of (noise-corrupted) estimates of the gradients.

LN- Location and Navigation. This feature gives the following information on station location: transmitter's state, city, latitude, and longitude (in the form of a computed grid number).

Long-term integration- Special camera mode similar to the ‘B’ setting of a photographic camera shutter. The CCD integrates over a long (userdefined) period, providing very high sensitivity. Object must be stationary, external camera control and a frame memory are needed.

Loop- The loop formed by the two subscriber wires (tip and ring), connected to the telephone at one end and the central office (or PBX) at the other end. Generally, it is a floating system, not referred to ground or AC power.

LPC- Linear Predictive Coding. A particular form of redundancy removal, where a "linear predictor" is created to remove the redundancy due to vocal tract (or other signal generation) effects. LPC is commonly used in a speech coder because this method allows for good tracking of the redundancy introduced by the human vocal tract.

LT- Line Termination, generally CO line card.

LR- Location Register.

Luminance- The part of a composite video signal that expresses brightness. Also called Y. Separately transmitted in Y/C (S-video).

Lux-The SI measurement of light intensity taken at the surface which the light source is illuminating. The measure of the total lumens falling upon a unit of area. 1 lumen per square meter. One Foot-candle equals 10.76 lux.

M -back to top

M/S Mode- Mono/Stereo Mode.

MAE- Mean Absolute Error.

MAP- Maximum A Posteriori. A detection hypothesis that maximizes the a posteriori probability.

MB- Macroblock

MBA- Macroblock Address.

Mbps- Megabits Per Second.

MC- Motion Compensation or Model Compliance.

MCBPC- Macroblock type and Coded Block Pattern for Chrominance.

MCI- Multiplex Configuration Information. Information defining the configuration of the multiplex. It contains the current (and in the case of an imminent reconfiguration, the forthcoming) details about the services, service components, subchannels, and the linking between these objects. It is carried in the FIC in order that a receiver may interpret this information in advance of the service components carried in the main service channel. It also includes identification of the ensemble itself and a date and time marker.

MCM- Multicarrier Modulation. A parallel digital modulation scheme that simultaneously modulates a number of carriers.

MDCT- Modified Discrete Cosine Transform.

ME- Motion Estimation.

MELP- Mixed-Excitation Linear Predictive coding.

Memory Card- A small removable memory unit, containing digital integrated circuit memory chips, housed in a rugged package.

Minimum illumination- Minimum light level needed to achieve a 50% or 100% video output level when the camera is at maximum gain and the lens iris fully open. Can be computed from the nominal sensitivity, lens characteristics and maximum gain.

Minimum Object Distance-MOD. A lens parameter that defines the minimum distance from a camera lens to the point where an object can still be in focus.

MIPS- Millions of Instructions Per Second. A measure of microprocessor power.

Mixed Signal - The combination of analog and digital circuits on the same semiconductor die.

MMDS- Multichannel Multipoint Distribution Service. A microwave local distribution system providing multiple television channel programs (up to 33 channels) to subscribers.

MMSE- Minimum Mean-Square Error

MOD- Magneto-Optical Disk.

Motion Detector-MD. Camera feature where a reference field is compared with current fields. If a difference is detected, the camera outputs a pulse. An ideal feature for security application.

Modulation Transfer Function- MTF. Defines the resolution capability of a lens. Most lenses exhibit their best MTF when operated in the middle of their iris aperture range.

MPAC- Multichannel Perceptual Audio Coding (AT&T).

MPEG- Moving Pictures Expert Group.

MS-Mobile Station.

MSC- 1. Mobile Switching Center. 2. Main Service Channel. A channel that occupies the major part of the transmission frame and carries all the digital audio service components, along with possible supporting and additional data service components.

MSE- Mean Square Error.

MSK- Minimum Shift Keying. A special case of continuous phase-FSK wherein the peak frequency deviation is equal to half the bit rate, which is the minimum frequency spacing for two frequency-shift keying signals.

MTF- Modulation Transfer Function. A representation of the human visual system's response to visual stimuli at various frequencies.

MV- Motion Vector.

MVD- Motion Vector Data.

N -back to top

NBC - Non-Backward Compatibility.

NCMFSK - Noncoherent Multilevel Frequency Shift Keying.

ND (Neutral Density) Filter - A grey filter added in front of a lens to reduce the amount of incoming light into the camera lens. It has no influence on color.

NF Mount- Type of camera mount in which there is 12 mm clearance between the lens rear mounting surface and the camera’s CCD.

NMR- Noise-to-Mask Ratio.

Noiseless Coding- Coding methods that do not remove any information present in the signal, i.e., that allow for perfect reconstruction of the original digital input signal. The classic set of noiseless coders are the information-theoretic coders such as Juffman coders. Ziv-Lempel coders, and arithmetic coders. However, other coders -- including subband, transform, and other source coders -- can be used as noiseless coders in some circumstances. A particular example is lossless JPEG.

Non-Linear Editor- Video editing using a computerized system, where data can be stored on a digital medium so that video can be manipulated outside of real time.

NT- Network Termination. A connection between terminal equipment (TE) and the network.

NT1- Converts two-wire U-interface to four-wire S/T interface.

NTSC- National Television System Committee. NTSC (National Television System Committee): Color video standard, used mainly in the United States and Japan. NTSC uses 525 scanning lines per picture, 30 pictures (frames) per second, each frame is made up of two sequential fields containing respectively the even and the odd lines (interlace).

NVOD- Near Video-On-Demand.

O -back to top

OBO- Output Back-Off. The output power of a power amplifier in a modulation system that is needed to back off from the saturation point of the amplifier to avoid nonlinear distortion.

OFDM- Orthogonal Frequency Division Modulation or Multiplexing. A multicarrier modulation scheme that involves multiplexing a number of low-speed modulated carriers for transmission.

Off-Hook- The condition in which the telephone is connected to the phone system, permitting loop current to flow. The central office detects the DC current as an indication that the phone is busy.

Offline Editor- A computer system where editing can take place with extreame flexibility. This is an inexpensive method of editing.

On-Hook- The condition in which the telephone's DC path is open and no DC loop current flows. The central office regards an on-hook phone as available for ringing.

One-pass tape- Any tape format that has been recorded to once. This can then inspected, erased and cleaned, then sold as evaluated tape.

One-push AF (Auto Focus)- Focus hold mode that can be automatically readjusted as required by the user (One-push AF Trigger) assuming that the required subject is within the focusing limits of the camera lens.

Online Editor- An editing system where the final video master is made.

Optical Prefilter- An optically transmissive device, such as a stack of birefringent quartz plates, that limits the high-frequency content of an image focused on a solid-state image sensor in order to reduce aliasing.

OQPSK- Offset Quadrature Phase-Shift Keying, where on quadrature arm is offset by one bit duration relative to the other arm.

P -back to top

PABX, PAX-Private Automatic Branch Exchange. A customer-owned, switchable telephone system providing internal and/or external station-to-station dialing.

PAC- Perceptual Audio Coding (AT&T).

Packet- A group of binary digits that is switched as a composite whole with data, control, and error elements arranged in a specified format. A packet consists of a header followed by a number of contiguous bytes from an elementary data stream.

Packet Mode- The mode of data transmission in which data is carried in addressable blocks called packets. Packets are used to convey MSC data groups within a subchannel.

PACS- The mode of data transmission in which data are carried in addressable blocks called packets. Packets are used to convey MSC data groups within a subchannel.

PAD- Program-Associated Data. Information that is related to the audio data in terms of contents and synchronization. The PAD field is located at the end of the DAB audio frame.

PAL- Phase-Alternating Line.

PAM- Pulse Amplitude Modulation. A digital amplitude-modulation scheme

PAR- Peak-to-Average power Ratio (usually expressed in decibels [dB]) that is used to determine the robustness of a modulated signal against nonlinear distortion.

PASC- Precision Audio Subband Coding (Philips).

PAT- Program Association Table. Provides the association between a program number and the PID(Packet Identifier) value of the transport stream packets, which carry the program definition.

Payload- A generic term referring to the bytes that follow the header bytes in a packet.

PCMCIA- Personal Computer Memory Card Industry Association. A nonprofit trade association founded in 1989 to define a standard memory card interface for computers.

PCR- Program Clock Reference. A time stamp in the transport stream from which decoder timing is derived.

PCS- Personal Communication Systems or Services.

PDC- Pacific Digital Cellular. A cellular standard that was developed in 1991 to provide for needed capacity in congested cellular bands in Japan.

Perceptual Coding - A lossy form of coding where parts of the signal that are not perceptible to the end user are removed. Perceptual coding is always lossy and is in some sense the dual of source coding, i.e., "destination coding," where information important to the destination (human being) is preserved and information not important is removed.

PES- Packet Elementary Stream. Consists of PES packets, all of whose payloads consist of data from a single elementary stream, and all of which have the same stream identifier.

PFD- Phase and Frequency Detector used for decision-directed carrier recovery.

Photo CD Disc- A compact disc-recordable (CD-R) optical write-once disc that stores scanned photographic images using the Image Pac image data format.

PHS- Personal Handy Phone System. A Japanese air interface standard set by the Research and Development Center for Radio Systems; its network interface was specified by the Telecommunications Technical Committee of Japan in 1993.

PI- Program Identification. This information consists of a code that enables a receiver to identify the program. The code is not intended for direct display to the user, rather it is sort of a program ID to allow distinction from all other programs. This is valuable for "scanning" and "learning" receivers (with or without memory), which are equipped to switch over to an alternate transmitter with the same program (NPR radio affiliates, for example, often broadcast the same program at the same time).

PID- Packet Identifier. A unique integer value used to associate elementary streams of a program in a single or multiple program MPEG-2 transport stream.

PIN- Program Item Number. A number that can be used by a "smart radio" to tune a specific program at a particular time when the program has come on the air. It allows for consumer convenience in receiving special programs.

Pixel, Pel, Picture Element- The smallest area of a television picture capable of being delineated by an electric signal passed through the system or part of it.

PMT- Program Map Table. Provides the mappings between program numbers and the elementary streams that make up the program.

POTS- Plain Old Telephone Service.

PRA- Pel Recursive Algorithm.

Program- A collection of elementary streams with a common time base.

PS- Program Service. This is a text of not more than eight alphanumeric characters coded in conformity with the standard and used to display the service name of the broadcasters. Examples of PS names are "WABC," "WXYZ," "G-100," "HOT93," or "COOL99".

PTY- Program Type. This is an identification number to be transmitted with each program; it will identify the "type" or "category" of the program content. There are 31 codes allowed and in the RBDS U.S. standard, 22 categories plus emergency alert have been decided on. 15 is for classical music, and the display will show "CLASSICL" -- lacking the "A" because only eight characters are allowed.

PTYN- Program-Type Name. An alternate name to be displayed after the PTY search if the broadcaster wants to give a more specific music format.

Progressive (Sequential) Scanning - A rectilinear scanning process in which the distance from center to center of successively scanned lines is equal to the nominal line width.

PS- Program Stream. Consists of contiguous PES packets that comprise one or more video or audio elementary streams.

PSI- Program-Specific Information. Consists of normative data necessary for the demultiplexing of transport streams and the successful regeneration of programs

PSI-CELP- Pitch-Synchronous Innovation Code Excited Linear Predictive coding.

PSK- Phase-shift keying. A digital phase-modulation scheme.

PSNR- Peak Signal-to-Noise Ratio.

PSTN- Public Switched Telephone Network.

PTS- Presentation Time Stamp. A field that may be present in a PES packet header that indicates the time that a presentation unit is presented in the system target decoder.

PU- Presentation Unit. A decoded audio frame or a decoded picture.

Q -back to top

Q- Quadrature component.

QAM- Quadrature-Amplitude Modulation. A combined phase- and amplitude-modulation scheme that is used to modulate the carrier signal in phase quadrature.

QCELP- Qualcomm Code Excited Linear Predictive coding.

QCIF- Quarter CIF.

QPSK- Quadrature or Quaternary Phase-Shift Keying. A digital phase-modulation scheme that is used to modulate the carrier signal in phase quadrature.

Quantization-A process by which information, redundancy, and irrelevancy are removed from a signal. A quantizer is a construct that takes an amplitude-continuous signal and converts it to discrete values that can be reconstructed by a decoder.

Quantize-To subdivide the range of values of a variable into a finite number of nonoverlapping subranges or intervals, each of which is represented by an assigned value within the subrange.

R -back to top

Random Access -The process of beginning to read and decode the coded bitstream at an arbitrary point.

Redundancy- Parts of a signal that are, because of the process(es) that generated it, predictable or in some way related to other parts of the same signal. In a strict sense, redundancy in a signal is not part of the information content of that signal as it may be removed at the encoder, and restored at the decoder, with no loss of content.

RF- Radio frequency that is above the audio and below infrared frequencies. The frequency range is 10 kHz to 10 GHz, allocated for radio use.

Ring- One of the two wires connecting the central office to CPE. The name derives from the ring portion of the plugs used by operators in older equipment to make the connection. Ring is traditionally negative with respect to tip.

RISC- Reduced Instruction Set Computer. A CPU architecture that optimizes processing speed by using a smaller number of basic machine instructions.

RJ-11- Standard four-wire analog phone connector.

RJ-45- Standard eight-wire ISDN connector.

RP- Radio Paging. The RP feature is intended to provide for numeric and alphanumeric paging via the FM radio transmitter. Already, several international paging operations are in progress. RDS paging receivers are not unlike those already in the marketplace; they are merely operating at a different frequency and from an already installed transmitter.

RPE-LTP- Regular Pulse Excited linear predictive coding with Long-Term Prediction.

RT- Radiotext. For receivers suitably equipped with a display, messages could be sent to the listener giving information about the program being broadcast or advertiser-supported messages. A voice synthesizer could be controlled by the radiotext code, for example, to enunciate a certain message in the absence of a display.

S -back to top

S/T Interface- Four-wire interface between terminal equipment (TE) and network termination (NT).

SCM- Single-carrier modulation, in which information data is modulated on one carrier for transmission.

SCR- System Clock Reference. A time stamp in the program stream from which decoder timing is derived.

Scrambling- The alteration of the characteristics of a video, audio, or coded data stream in order to prevent unauthorized reception of the information in a clear form.

SCTE- Society of Cable Telecommunications Engineers.

SCWID- Spontaneous Call-Wire Identification Delivery (type II) -- see CIDCW.

SECAM- Sequentiel Couleur Avec Memoire.

SER- Symbol Error Rate. A measure of probability of symbol errors in a communication system.

SFN- Single-Frequency Network. A network of DAB transmitters sharing the same radio frequency to achieve a large-area coverage.

Signaling- The transmission of control or status information in the form of dedicated bits or channels of information inserted on lines with voice data.

Simultaneous Contrast- A measure of the perceived difference between two adjacent patches of light.

SLM- Signal Level Meter.

SMPTE- Society of Motion Picture and Television Engineers.

SMR- Signal-to-Mask Ratio

SNR- Signal-to-Noise Ratio. The measure of the energy in the signal (usually expressed in decibels [dB]), within a certain bandwidth and/or time, versus the energy of the noise that was added to the signal by some process. In this context, noise refers not only to added random noise but to any other difference, other than simple scaling, present in the reconstructed signal. In video, a variant of SNR called PSNR (peak signal-to-noise ratio) is often used; this corresponding to the energy of the noise versus the maximum possible signal energy.

SONET- Synchronous Optical Network, which specifies data transmission over optical fiber with rates ranging from 51.84 Mb/s to 9.95 Gb/s.

Source Coding- Techniques that use the redundancy in a signal to reduce the bit rate. Some source coders (noiseless coders) remove only redundancy and provide perfect reconstruction of the decoded signal. Tohers remove redundancy and some information as well and provide a noisy decided signal, but usually with unobjectionable noise characteristics. Typical kinds of source coding are LPC, ADPCM, CELP, subband, and transform.

SPA- Significant pel area.

Splicing- The concatenation, performed on the system level, of two different elementary streams. The resulting system stream conforms totally to the MPEG-2 system standard. The process may result in discontinuities in time base and decoding.

SSM- Spread-spectrum modulation. A digital modulation scheme that spreads the system bandwidth far greater than the minimum required bandwidth.

Start Code- A 32-bit code word embedded in the coded bitstream that is unique. The start codes are used for several purposes, including identifying some of the layers in the coding syntax, and they consist of a 24-bit prefix (0x000001) and an 8-bit stream ID.

STD- System Target Decoder. A hypothetical reference model of a decoding process used to describe the semantics of the MPEG-multiplexed bitstream.

Stream ID- Stream Identifier. An 8-bit unique word used to define a video, an audio, or other PES packet.

Stream Mode- The mode of data transmission within the Main Service Channel, in which data are carried transparently from source to destination. Data are carried in logical frames.

Subband- A subdivision of the audio frequency range. In the audio coding system, 32 subbands of equal bandwidth are used.

Subchannel- A part of the main service channel that is individually convolutionally encoded and comprises an integral number of capacity units per common interleaved frame.

SVF- Still Video Floppy. A standardized recording medium for analog electronic still cameras developed in the early 1980s. SVF cameras use a 2-inch-diameter floppy disk capable of storing either 50 field images or 25 frame images.

Synchronization Channel- A part of the transmission frame provided to ensure proper time, frequency, and phase synchronization in the receiver.

T -back to top

TA- 1. Terminal Adapter. Takes a non-ISDN data stream and converts it to the ISDN data format; used to provide S/T or U-interface connection to type 2 terminal equipment (non-ISDN-compliant). 2. Traffic-Announcement Identification. This is an indicator to show when the actual traffic announcement is in progress. It can be used by the receiver to switch from its current mode over to the traffic announcement on the main audio channel, and then back to the previous setting after the traffic announcement concludes.

TCE- Thomson Consumer Electronics.

TCM- Trellis-Code Modulation. A combined coding and modulation technique.

TDC- Transparent Data Channel. These channels could be used to send alphanumeric characters, or other text, or for transmission of computer program data or similar information not intended to display on the user's set.

TDMA- Time-Division Multiple Access. A time-slot-based multiuser access scheme.

TE- Terminal Equipment. Type 1 (TE1) is ISDN-compliant. Type 2 (TE2) requires a terminal adapter to connect to the network.

Telephone Bandwidth- Usually 200 Hz to 3200 Hz, although some algorithms and transmission facilities provide signals from 50 Hz to 3600 Hz, depending on the situation and equipment involved.

THM- Time-Hopping Modulation. A spread-spectrum technique using pseudorandom time-hop patterns as the spreading sequence code; it is analogous to pulse-position modulation.

TIA- Telecommunication Industry Association. A trade organization that provides services such as government relations, market activities, educational programs, and standards-setting activities.

Time Code- A time reference recorded on tape to give a time reference for each frame in video.

Time Stamp- Indicates the time of an event such as the arrival of a byte or the presentation of a presentation unit.

Tip- One of the two wires connecting the central office to SPE. The name derives from the tip of the plugs used by operators in older equipment to make the connection. Tip is traditionally positive with respect to ring.

TMN- Test Model for Near-term solution (H.263).

TOV- Threshold of Visibility. A bit-error-rate HDTV threshold of 3 x 10-6, at which value the impairment effect first becomes visible in the picture.

TP- Traffic-Program Identification. This is a digital flag sent by the broadcaster to turn on the lamp or other signal within the receiver to indicate to the user that the broadcaster is giving traffic announcements (when the lamp does not light, it means that the station is not giving traffic announcements at the time).

TR- Timing Recovery for symbol synchronization.

Transmission Frame- The actual transmitted frame -- specific to the three transmission modes -- conveying the synchronization channel, the fast information channel, and the main service channel.

Transmission Mode- A specific set of transmission parameters (e.g., number of carrier, OFDM symbol duration). Three transmission modes (i.e., I, II, III) are defined to allow the system to be used for different network configurations and a range of operating frequencies.

TS- Transport Stream. Contiguous packets, each of which is 188-bytes in length, consisting of one or more PES packets.

TTIB- Transparent Tone In Band. A pilot-aided carrier recovery technique.

U -back to top

UEP- Unequal Error Protection.

U-Interface- A two-wire interface between network termination (NT) and line termination (LT).

U-TA- U-interface Terminal Adapter. Converts non-ISDN data stream to ISDN data format; used to provide U-interface connection to type 2 terminal equipment in North America.

V -back to top

VAR- Variance.

VBR- Variable Bit Rate. An operation in which bit rate varies with time during the decoding of a compressed bitstream.

VCR- Videocassette Recorder.

VLC(D)- Variable Length Coding (Decoding).

VLIW- Variable-Length Instruction Word. A new CPU architecture that relies on a variable-length word size and small parallel processors to provide throughput in terms of billions of operations per second.

VOD- Video On Demand.

VSB- Vestigial Sideband. The transmitted portion of one sideband; the sideband is suppressed in a transmitter having a gradual cut-off in the neighborhood of the carrier frequency. Meanwhile, the other sideband is transmitted without suppression.

VSELP- Vector-Sum Excited Linear Predictive coding.

W -back to top

WACS- Wireless Access Communication System. Developed to provide wireless connections for local exchange carriers.

White Balance- A process for adjusting the relative signal levels of the red, green, and blue channels from a camera to correct for the color of the light source illuminating a scene, so that objects that appear to be white in the scene are reproduced as white on the soft-display or hard-copy print.

Wideband Speech- Speech having a bandwidth of 60 Hz to 7 kHz, also referred to as commentary grade or remote contribution quality.

WLAN- Wireless Local-Area Network.

X -back to top

X-sync- The maximum (fastest) shutter speed at which electronic flash pictures may be taken.

XY Stereo- XY stereo set-up is a coincidence stereo technique using two cardioid microphones in the same point and angled at 90° to produce a stereo image. Theoretically, the two microphone capsules need to be at exactly the same point in space to avoid any phase problems due to the distance between the capsules. As this is not physically possible, the nearest approximation is to place one microphone on top of the other with the diaphragms vertically aligned. In this way, sound sources in the horizontal plane are picked up as if the two microphones were placed at the same point. However, channel separation is limited, and wide stereo images are not possible. But the XY stereo method is highly mono-compatible and is used in broadcasting situations where listeners might be listening to stereo audio on mono equipment.

Y -back to top

Y/C - (also called S-Video) Separate signals for the Luminance and Chrominance parts of the video signal. Allows higher picture resolution and suppresses cross color effects. Connector is the 4-pin mini-DIN.

Y/R-Y/B-Y- Three signals, luminance (Y) and two color difference signals R-Y (red minus luminance) and B-Y (blue minus luminance) which together carry the brightness and color information of color images . Color difference signals have no light intensity information, and cannot be displayed separately from Y. Compared to RGB signals, they can travel over longer cables lengths without significant resolution loss, and allows different spatial resolutions for luminance and color. Typically used for high-end visual applications. Also known as component signals. See also U and V signals.

Z -back to top

Zoom Triggered AF- The camera is normally in fixed focus mode, but AF(Auto Focus) is temporarily switched on each time the zoom ratio of the camera lens is changed.