As NTSC video is digitized, the luminance (Y) and chrominance (R-Y and B-Y) of the signal is sampled and recorded as numeric values. The designation "4:2:2 digital video" indicates that for every four luminance samples, the R-Y and B-Y components are sampled twice. The 4:2:2 sampling is a part of the ITU 601 standard employed by the D1 digital videotape format.
Bittree specific, 2x24 Long Frame audio patchbays with various rear interfaces.
Bittree specific, 2x24 Long Frame audio patchbays that allow the user to change the normalling and grounding scheme for individual circuits by changing the position of the shunts located underneath the designation strips. Available with various rear interfaces.
Bittree specific, 2x26 Long Frame audio patchbays with various rear interfaces.
Bittree specific, 2x48 Bantam (TT) patchbays with various rear interfaces.
Bittree specific, 2x48 Bantam (TT) audio patchbays that allow the user to change the normaling and grounding scheme for individual circuits by changing the position of shunts located within the unit's case. Available in a 1RU configuration only, with various rear interfaces.
Bittree specific, 2x48 Bantam (TT) audio patchbays that allow the user to change the normaling and grounding scheme for individual circuits by changing the position of the shunts located underneath the designation strips. Available in 1.5 and 2RU configurations, with various rear interfaces.
A device used to convert analog signals to digital signals.
ATSC is composed of corporations, associations and educational institutions, developing voluntary standards for the entire spectrum of advanced television systems, including high-definition television. In 1996, the U.S. FCC adopted the major elements of the ATSC Digital Television (DTV) Standard, mandating its use for digital terrestrial television broadcasts in the U.S.
An acronym for Audio Engineering Society/European Broadcasting Union, AES/EBU commonly refers to the digital audio transfer standard they developed. The AES/EBU digital interface is usually implemented using standard 3-pin XLR connectors, with one cable carrying both left- and right-channel audio data.
A measurable characteristic that varies continuously over time, such as voltage, pressure, or temperature. A standard "off-air" television signal is an analog signal. An analog device operates by creating or responding to such signals
In video, signals are asynchronous when their timing differs one from another. Switching between asynchronous sources usually produces an undesirable flicker and momentary color shift (in NTSC). Systems within a properly designed facility are linked to a master clock and are therefore synchronous. A foreign video signal is asynchronous, but can be brought "into time" by patching or routing it through a local frame synchronizer.
In audio, a signal utilizing two conductors, generally referred to as positive and negative, in addition to a shield (or ground). The main advantage of a balanced signal is that noise introduced into the line is common to both the positive and negative conductors, and arrives at its destination out of phase, where it effectively cancels itself. See also, "Unbalanced.”
The range of frequencies required for a circuit to function with minimal loss. The bandwidth allotted for an analog television channel in the U.S. is 6MHz. HDTV signals can require a bandwidth of 2.25GHz. Current Bittree video panels support a bandwidth of up to 3GHz.
Originally know as TT (see "TT") it refers to Switchcraft's smaller version of the original Long Frame (1/4") phone plugs. The term "Bantam" (from the boxing weight class) was later used to avoid infringing on Switchcraft's trademarked name for the smaller standard. Bantam (TT) plugs allow for higher density patch panels. This is especially useful in installations where space in an issue, or when pairing stereo audio panels (48 jacks) with corresponding video panels (24 jacks).
The frequency band occupied by the aggregate of the signals used to modulate a carrier.
A type of coaxial connector often found on video and digital audio equipment, as well as on test devices like oscilloscopes. In audio gear, BNC connectors are normally used to carry synchronizing clock signals between devices. BNC’s are bayonet-type connectors, inserted and then secured with a half turn. All of Bittree’s video patchbays accept BNC connectors on the back. BNC’s are named for their type (Bayonet), and their inventor, Neill Concelman.
In patchbays, a unit in which all wiring is enclosed in a box, or chassis, as opposed to configured as a harness.
A device that converts a signal into a digital format for transmission and also converts received digital signals back into their original format. Codecs generally perform A to D, D to A, compression, and possibly encryption functions.
A video signal that includes color difference components. Components are created by subtracting luminance and/or color information from one of the primary color signals (red, green or blue). Betacam and MII are two widely used color difference formats.
RGB and Y, R-Y, B-Y are commonly called component signals, existing as individual red, green and blue components or as luminance and chrominance values. The components eventually make up the composite video signal, but are better recorded and transmitted throughout a facility separately, allowing each channel more bandwidth and avoiding loss due to the combination of signals.
A video signal in which the component parts of a video signal have been combined.
A device used to convert digital signals to analog signals.
A standard 9-pin connector used for data transfer, as in RS-232 communications. Bittree's data patchbays feature standard DB-9 connectors on the backplane, and the sturdy, easily patchable Dual Bantam jacks on the front.
Circuitry in which data carrying signals are restricted to either of two voltage levels, corresponding to logic 1 or 0. Such a circuit has two stable states: high or low, on or off.
A device used to replicate an input signal, typically providing six or eight outputs, each of which is identical to the input. Useful for providing additional recording and monitoring sources from a single signal. A DA may include additional equalization capabilities.
Two Bantam (TT) plugs used in tandem, useful for stereo audio applications. Dual Bantam patchcords are used with Bittree's data patchbays.
Denotes Bittree's original 3-pin connector used to terminate the three conductors of a balanced audio circuit. These connectors are options on the backplane of Bittree audio patch panels. As opposed to E90 or Punchdown, their main advantages are 1) they can be easily moved to a new patch position in case of a change order or wiring mistake, and 2) they make checking and correcting phase mistakes (red/black/ground orientation) very easy, as inconsistencies are obvious. Another advantage is that the ends can be assembled off-site, meaning that plugging them in is all that is required on-site.
Denotes an Elco 90-pin connector used to terminate multiple audio pairs onto one screw-down connector. These connectors are options on the backplane of Bittree audio patch panels. E90 connectors present an excellent solution for integrating systems that may be separated for travel, as panels can be disconnected/reconnected in the time it takes to screw down only two or four durable connectors. Additional advantages are that the ends can be assembled off-site and the ease with which changes can be made to the panel's configuration. For example, moving a point within a connector is a change of only an inch or so, all but eliminating the possibility that a cable would have trouble reaching its new destination. See also E3 and Punchdown, other backplane options.
A type of multi-pin connector used in audio systems and equipment for connecting multi pair cable with one connector, instead of many. E3 refers to Bittree's original 3-pin connector, E90 refers to a 90 pin Elco connector. Bittree offers these connectors as options for the backplane of its audio patchbays. See also E3, E90, and Punchdown.
The number of complete cycles of a periodic waveform that occur in a given length of time. Usually specified in cycles per second (Hertz).
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One billion cycles per second.
An acronym for General Purpose Interface, referring to an interface allowing one machine to trigger events on another, such as an edit controller triggering a video dissolve or an audio cross-fade. GPI's can be wired through an audio patchbay giving the operator easy access to the GPI ports of various machines.
In electronics, the reference from which system signals are measured. The ground lead usually has "zero potential," or no electric charge, and also provides a path of least resistance to earth (as opposed to through an operator!) should a problem occur.
Describes the grounding scheme of an audio patch panel, whereby the shield of each circuit is isolated from the front panel and each other.
Describes the grounding scheme of an audio patch panel, whereby audio circuits have a common shield, isolated from the front panel and bussed to a ground connector on the rear panel.
Describes the grounding scheme of an audio patch panel, whereby each pair of audio circuits has shields common, but isolated from the front panel and adjacent circuits.
Describes the grounding scheme of an audio patch panel, whereby the shield of each circuit is brought out to the backplane to allow manual normaling of individual positions.
Same as Grounds Out, however, inserting a patchcord lifts the shield.
Same as Looped Ground, however, inserting a patchcord lifts the shield.
In patchbays, the length of cable connecting the front panel and backplane. A harness configuration (as opposed to chassis) allows the front and back to be mounted separately, wherever is most convenient. The harness connecting the two can be of any length.
The SMPTE in the USA and ETA in Japan have proposed a high definition television product standard including: 1125 lines at 60Hz field rate 2:1 interlace; 16:9 aspect ratio; 30MHz RGB and luminance bandwidth.
In patchbays, the insertion and removal of a patchcord. The durability of a jack is rated in insertion cycles.
Short for interlaced scanning. A system of video transmission whereby all the odd number lines are delivered followed by all the even numbered lines. These two “fields” combine to form a single frame of video.
Bittree specific, a single patch panel having video, audio and possibly data patch points. Especially useful in edit bays where all signal types are present, but there may not be the need or space for a separate panel for each type.
A jack is basically the opposite of a plug. It is the receptacle into which one inserts a patch plug. A patchbay is sometimes referred to as a "jack field."
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One thousand hertz. Audible sound is between 20Hz to 20kHz. (The "Kilobyte" abbreviated "Kb", refers to 2 to the power of 10 bytes, or 1024 bytes.)
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The original 1/4” standard phone plugs as developed by Western Electric and AT&T, also used in audio patching systems. 1/4" jacks have long been the standard in audio patching, but as space and even weight become more of an issue, the higher density Bantam (TT) panels are often preferable.
A two-pronged plug designed as a manual, external normal for a pair of video jacks.
One million hertz.
A smaller version of the standard WECO video jack, allowing a density of up to 32 jacks across a rack mountable panel.
Compression standards for moving images conceived by the Motion Pictures Expert Group, an international group of industry experts set up to standardize compressed moving pictures and audio. MPEG-2 is the basis for ATSC digital television transmission.
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A term used to describe a circuit that is completed. In the case of a patchbay, the TOP row of patch points (generally signal source points) is usually normalled to the bottom row (generally signal destination points) on a one to one basis. Inserting a patch cable into any one of the patch points breaks the normal in favor of the patch cable. The exception is in the case of a half-normalled audio circuit.
On a patchbay, a jack that is not normalled to another. Any signal connected to a non-normalled jack would be available only through the use of a patch cable or looping plug. A self-terminating non-normalled video jack is terminated when the patchcord is removed.
A term used in specifying an audio patchbay to indicate internally normalling circuits.
A term used in specifying an audio patchbay, indicating normalling circuits that are available externally (on the backplane) to allow manual normalling of individual positions.
A term used to describe an audio circuit that is normaled through a patchbay, with the additional characteristic that when a patch cord is inserted into the top (source point) of a jack, the signal is split such that it continues through to its normal at the same time it is available to the patch cord. A patch cord inserted into the bottom (destination point) breaks the normal so as to avoid mixing signals from the original source point. Half-normaling is not recommended for use with AES/EBU circuits.
A term used in specifying an audio patchbay to indicate internally normalling, half-normaled circuits.
A term used in specifying an audio patchbay, indicating half-normalling circuits that are available externally (on the backplane) to allow manual normalling of individual positions.
National Television Standards Committee formed in 1953, part of the Electronic Industries Association (EIA). The acronym is commonly used to describe the system of color telecasting which is used mainly in North America, Japan and parts of South America.
An acronym for “phase alternation by line” used to describe the system of color telecasting which is used mainly in Europe, China, Malaysia, Australia, New Zealand, the Middle East and parts of Africa.
Patchbays are an integral part of any professional video production or transmission facility, used to bridge the video, audio and data inputs and outputs from one piece of machinery to the next. Patchbays, also known as patch panels or patching systems, provide patching points, allowing an operator to easily re-route a signal by the simple insertion of a patch cable. Patching systems within a properly wired facility also help an engineer or operator to quickly identify the source of a problem, and often bypass or replace defective machinery while it is serviced.
A short cable made for insertion into a patchbay.
Bittree specific, used to indicate an audio patchbay with a series of shunts hidden under the designation strip used to change normaling and grounding schemes from the front of the panel, rather that having to re-wire the back. Also useful in mixed systems, where analog signals might be half-normaled with bussed grounds, while digital signals are full normaled with looped grounds.
Short for progressive scanning, a system of video scanning whereby lines of a picture are transmitted consecutively, as opposed to interlaced. Typically used by VGA monitors.
Denotes a patchbay backplane that is wired with a standard "punchdown tool" which connects leads and clips excess wire in one simple step. These connectors are options on the backplane of Bittree audio patch panels. This type of backplane is best used in installations where alterations are not expected. The main advantage of this system is the single step with which the leads can be connected and clipped, as opposed to building a connector to be plugged in. The disadvantages are that all the work needs to be done directly on the panel, and mistakes are harder to see and correct. See also E3 and E90, other backplane options.
A rack unit is a measurement of height equal to 1.75". Additionally, the mountable area of a standard rack is 19" wide with holes pre-drilled so as to allow standard gear to be placed in only full rack unit increments. Rack depths vary. Rack mountable gear has mounting "ears" that bring the width of the unit to 19", height being measured in rack units, or RU's. While most patchbays are available in 1RU and 2RU configurations, Bittree has originated a 1.5RU panel, mountable in 1/2RU increments, allowing the use of full size designation strips on a panel less than 2RU.
The abbreviation for red, green, and blue, the primary colors of television (and light in general). However color video is recorded or transmitted, the end result is a series of red, green, and blue phosphors illuminated on the television screen that together form the intended images. Bittree manufactures panels designed specifically for carrying these separate components, and a patch cables to work with the panels.
As RGB, plus Horizontal and Vertical sync. Bittree manufactures panels designed specifically for carrying these separate video components.
A standard, unbalanced interconnection scheme for bi-directional serial data communications. The standard originally called for the use of a DB-25 connector, but now allows the smaller DB-9.
A standard, balanced interconnection scheme for data communication over twisted pair. Designed to work over longer distances, in the range of 3000+ feet.
In video patchbays, a normalled jack that terminates the unused side when a patchcord is inserted, or a non-normalled jack that automatically terminates the signal when a patchcord is not present.
Often used informally to refer to a serial digital television signal. Serial, meaning quite literally that each bit of each byte of digital information is transmitted in sequence, one at a time.
Jumpers located under the designation strips of Bittree programmable patchbays, used to change the normalling and grounding schemes of each circuit.
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Completing a circuit by connecting a resistive load to it. A video signal is terminated by a 75 ohm resistive load. When there are looping inputs, any unused looping input must be terminated to ensure proper signal levels.
TT is an abbreviation for "Tiny Telephone", referring to Switchcraft's smaller version of the original Long Frame (1/4") phone plugs. The term "Bantam" (from the boxing weight class) was later used to avoid infringing on Switchcraft's trademarked name for the smaller standard. Bantam (TT) plugs allow for higher density patch panels. This is especially useful in installations where space in an issue, or when pairing stereo audio panels (48 jacks) with corresponding video panels (24 jacks).
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In audio, a signal passed on two conductors, one of which is usually kept at ground. Noise induced into the line is not cancelled as it is in the case of a balanced circuit. Unbalanced signals are better kept to short runs. See also, "Balanced".
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The highest signal frequency that a specific video signal can reach. The higher the video bandwidth, the better the quality of the picture. System components must be able to exceed the bandwidth of the signals they are intended to support.
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An abbreviation for Western Electric Company, WECO has come to describe the standard jack used in video patch fields
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Trademarked name for circular 3-pin connectors developed by Cannon (now owned by ITT), "XLR" was originally nothing more than Cannon's part designation for the connector. XLR has since evolved into a generic industry term, and many manufacturers now make this style connector, including connectors referred to as mini-XLR, 4-pin XLR, and others. Standard XLR connectors are normally used to connect machinery supporting balanced audio.
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Luminance (Y), and color values consisting of the luminance deducted from the color red (R-Y) and luminance deducted from the color blue (B-Y). The format is known as “color difference”, but is commonly referred to as “component” video. This format is native to Betacam machines.