channel

chan·nel¹

C0240000 (chăn′əl)n.1. The bed of a stream or river.2. The deeper part of a river or harbor, especially a deep navigable passage.3. A broad strait, especially one that connects two seas.4. A trench, furrow, or groove.5. A tubular passage for liquids; a conduit.6. A course or pathway through which information is transmitted: new channels of thought; a reliable channel of information.7. often channels A route of communication or access: took her request through official channels.8. In communications theory, a gesture, action, sound, written or spoken word, or visual image used in transmitting information.9. a. Electronics A specified frequency band for the transmission and reception of electromagnetic signals, as for television signals.b. A continuous program of audio or video content distributed by a television, radio, or internet broadcaster.c. A company or other entity presenting such content.10. Computers A chatroom on an online network.11. The medium through which a spirit guide purportedly communicates with the physical world.12. A rolled metal bar with a bracket-shaped section.13. a. See ion channel.b. See protein channel.tr.v. chan·neled, chan·nel·ing, chan·nels also chan·nelled or chan·nel·ling 1. To make or cut channels in.2. To form a groove or flute in.3. To direct or guide along some desired course: channels her curiosity into research; channel young people into good jobs.4. To serve as a medium for (a spirit guide).5. To use or follow as a model; imitate: a politician channeling bygone conservatives to appear stronger on defense.

[Middle English chanel, from Old French, from Latin canālis; see canal.]

chan′nel·er n.

chan·nel²

C0240000 (chăn′əl)n. Nautical A wood or steel ledge projecting from a sailing ship's sides to spread the shrouds and keep them clear of the gunwales.

[Alteration of obsolete chainwale : chain + wale.]

channel

(ˈtʃænəl) n1. (Physical Geography) a broad strait connecting two areas of sea2. (Physical Geography) the bed or course of a river, stream, or canal3. (Nautical Terms) a navigable course through a body of water4. (often plural) a means or agency of access, communication, etc: to go through official channels. 5. a course into which something can be directed or moved: a new channel of thought. 6. (Electronics) electronics a. a band of radio frequencies assigned for a particular purpose, esp the broadcasting of a television signalb. a path for an electromagnetic signal: a stereo set has two channels. c. a thin semiconductor layer between the source and drain of a field-effect transistor, the conductance of which is controlled by the gate voltage7. a tubular or trough-shaped passage for fluids8. (Architecture) a groove or flute, as in the shaft of a column9. (Computer Science) computing a. a path along which data can be transmitted between a central processing unit and one or more peripheral devicesb. one of the lines along the length of a paper tape on which information can be stored in the form of punched holes10. (Metallurgy) short for channel ironvb, -nels, -nelling or -nelled, -nels, -neling or -neled11. to provide or be provided with a channel or channels; make or cut channels in (something)12. (tr) to guide into or convey through a channel or channels: information was channelled through to them. 13. (Alternative Belief Systems) to serve as a medium through whom the spirit of (a person of a former age) allegedly communicates with the living14. (tr) to exhibit the traits of (another person) in one’s actions15. (Architecture) (tr) to form a groove or flute in (a column, etc)[C13: from Old French chanel, from Latin canālis pipe, groove, conduit; see canal] ˈchanneller, ˈchanneler n

channel

(ˈtʃænəl) n (Nautical Terms) nautical a flat timber or metal ledge projecting from the hull of a vessel above the chainplates to increase the angle of the shrouds[C18: variant of earlier chainwale; see chain, wale¹ (planking)]

Channel

(ˈtʃænəl) n (Placename) the Channel short for English Channel

chan•nel¹

(ˈtʃæn l)

n., v. -neled, -nel•ing (esp. Brit.) -nelled, -nel•ling. n. 1. the bed of a stream, river, or other waterway. 2. a navigable route between two bodies of water. 3. the deeper part of a waterway. 4. a wide strait, as between a continent and an island. 5. a course into which something may be directed: to direct a conversation to a new channel. 6. a route through which anything passes or progresses: channels of trade. 7. channels, the official course or means of communication: going through channels to reach the governor. 8. a means of access: The Senate is his channel to the White House. 9. channeler (def. 2). 10. a flute in a column. 11. a frequency band of sufficient width for one- or two-way communication from or to a transmitter for TV, radio, CB radio, telephone, or telegraph communication. 12. bus ¹ (def. 5). 13. the two signals in stereophonic or any single signal in multichannel sound recording and reproduction. 14. a transient opening made by a protein structure embedded in a cell membrane, permitting passage of specific ions or molecules into or out of the cell: calcium channel. 15. a tubular passage for liquids or fluids. 16. a. any structural member, as one of reinforced concrete, having the form of three sides of a rectangle. b. a number of such members. c. a flanged metal beam or bar with a U-shaped cross section. v.t. 17. to convey through or as if through a channel. 18. to direct toward or into some particular course: to channel one's interests. 19. to excavate as a channel. 20. to form a channel in. 21. to reach, or convey messages from, by channeling: to channel an ancient Egyptian spirit. v.i. 22. to become marked by a channel: Soft earth channels during a heavy rain. 23. to perform channeling. [1250–1300; Middle English chanel < Old French < Latin canālis waterpipe; see canal]

chan•nel²

(ˈtʃæn l)

n. a horizontal timber or ledge built outboard from the side of a sailing vessel to spread shrouds and backstays outward. [1760–70; alter. of chain wale]

channel

Past participle: channelled
Gerund: channelling

Imperative
channel
channel

Present
I channel
you channel
he/she/it channels
we channel
you channel
they channel

Preterite
I channelled
you channelled
he/she/it channelled
we channelled
you channelled
they channelled

Present Continuous
I am channelling
you are channelling
he/she/it is channelling
we are channelling
you are channelling
they are channelling

Present Perfect
I have channelled
you have channelled
he/she/it has channelled
we have channelled
you have channelled
they have channelled

Past Continuous
I was channelling
you were channelling
he/she/it was channelling
we were channelling
you were channelling
they were channelling

Past Perfect
I had channelled
you had channelled
he/she/it had channelled
we had channelled
you had channelled
they had channelled

Future
I will channel
you will channel
he/she/it will channel
we will channel
you will channel
they will channel

Future Perfect
I will have channelled
you will have channelled
he/she/it will have channelled
we will have channelled
you will have channelled
they will have channelled

Future Continuous
I will be channelling
you will be channelling
he/she/it will be channelling
we will be channelling
you will be channelling
they will be channelling

Present Perfect Continuous
I have been channelling
you have been channelling
he/she/it has been channelling
we have been channelling
you have been channelling
they have been channelling

Future Perfect Continuous
I will have been channelling
you will have been channelling
he/she/it will have been channelling
we will have been channelling
you will have been channelling
they will have been channelling

Past Perfect Continuous
I had been channelling
you had been channelling
he/she/it had been channelling
we had been channelling
you had been channelling
they had been channelling

Conditional
I would channel
you would channel
he/she/it would channel
we would channel
you would channel
they would channel

Past Conditional
I would have channelled
you would have channelled
he/she/it would have channelled
we would have channelled
you would have channelled
they would have channelled

Thesaurus

Noun	1.	channel - a path over which electrical signals can pass; "a channel is typically what you rent from a telephone company"transmission channeltransmission - communication by means of transmitted signals
	2.	channel - a passage for water (or other fluids) to flow through; "the fields were crossed with irrigation channels"; "gutters carried off the rainwater into a series of channels under the street"gutter, trough - a channel along the eaves or on the roof; collects and carries away rainwaterlimbers - a channel or gutter on either side of a ship's keelson; carries bilge water into the pump wellpassage - a way through or along which someone or something may pass
	3.	channel - a long narrow furrow cut either by a natural process (such as erosion) or by a tool (as e.g. a groove in a phonograph record)groovedado - a rectangular groove cut into a board so that another piece can fit into itfluting, flute - a groove or furrow in cloth etc (particularly a shallow concave groove on the shaft of a column)quirk - a narrow groove beside a beadingrabbet, rebate - a rectangular groove made to hold two pieces togethertrack - a groove on a phonograph recordingrut - a groove or furrow (especially one in soft earth caused by wheels)imprint, impression, depression - a concavity in a surface produced by pressing; "he left the impression of his fingers in the soft mud"stria, striation - any of a number of tiny parallel grooves such as: the scratches left by a glacier on rocks or the streaks or ridges in muscle tissuewashout - the channel or break produced by erosion of relatively soft soil by water; "it was several days after the storm before they could repair the washout and open the road"
	4.	channel - a deep and relatively narrow body of water (as in a river or a harbor or a strait linking two larger bodies) that allows the best passage for vessels; "the ship went aground in the channel"body of water, water - the part of the earth's surface covered with water (such as a river or lake or ocean); "they invaded our territorial waters"; "they were sitting by the water's edge"canal - (astronomy) an indistinct surface feature of Mars once thought to be a system of channels; they are now believed to be an optical illusiongut - a narrow channel or straitrill - a small channel (as one formed by soil erosion)river - a large natural stream of water (larger than a creek); "the river was navigable for 50 miles"strait, sound - a narrow channel of the sea joining two larger bodies of watertideway - a channel in which a tidal current runswatercourse - natural or artificial channel through which water flows
	5.	channel - (often plural) a means of communication or access; "it must go through official channels"; "lines of communication were set up between the two firms"communication channel, linecommunicating, communication - the activity of communicating; the activity of conveying information; "they could not act without official communication from Moscow"back channel - an alternative to the regular channels of communication that is used when agreements must be made secretly (especially in diplomacy or government); "they negotiated via a back channel"lens - (metaphor) a channel through which something can be seen or understood; "the writer is the lens through which history can be seen"inter-group communication, liaison, contact, link - a channel for communication between groups; "he provided a liaison with the guerrillas"plural, plural form - the form of a word that is used to denote more than oneline of gab, patter, spiel - plausible glib talk (especially useful to a salesperson)
	6.	channel - a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance; "the tear duct was obstructed"; "the alimentary canal"; "poison is released through a channel in the snake's fangs"duct, epithelial duct, canalpore - any small opening in the skin or outer surface of an animalpassageway, passage - a path or channel or duct through or along which something may pass; "the nasal passages"canalis vertebralis, spinal canal, vertebral canal - the canal in successive vertebrae through which the spinal cord passesductule, ductulus - a very small ductcanaliculus - a small canal or duct as in some bones and parts of plantscanal of Schlemm, Schlemm's canal, sinus venosus sclerae - a circular canal in the eye that drains aqueous humor from the anterior chamber of the eye into the anterior ciliary veinsvenous sinus, sinus - a wide channel containing blood; does not have the coating of an ordinary blood vesselampulla - the dilated portion of a canal or duct especially of the semicircular canals of the earlachrymal duct, lacrimal duct, tear duct - any of several small ducts that carry tears from the lacrimal glandsnasolacrimal duct - a duct that carries tears from the lacrimal sac to the nasal cavityHaversian canal - any of the many tiny canals that contain blood vessels and connective tissue and that form a network in bonehepatic duct - the duct that drains bile from the livercanalis inguinalis, inguinal canal - oblique passage through the lower abdominal wall; in males it is the passage through which the testes descend into the scrotum and it contains the spermatic cord; in females it transmits the round ligament of the uterusbile duct, common bile duct - a duct formed by the hepatic and cystic ducts; opens into the duodenumpancreatic duct - a duct connecting the pancreas with the intestinelymph vessel, lymphatic vessel - a vascular duct that carries lymph which is eventually added to the venous blood circulationsalivary duct - a duct through which saliva passes from the salivary gland into the mouthaqueductus cerebri, cerebral aqueduct, Sylvian aqueduct - a canal connecting the third and fourth ventriclesureter - either of a pair of thick-walled tubes that carry urine from the kidney to the urinary bladderurethra - duct through which urine is discharged in most mammals and which serves as the male genital ductcanalis cervicis uteri, cervical canal - a spindle-shaped canal extending from the uterus to the vaginaumbilical, umbilical cord - membranous duct connecting the fetus with the placentavagina - the lower part of the female reproductive tract; a moist canal in female mammals extending from the labia minora to the uterus; "the vagina receives the penis during coitus"; "the vagina is elastic enough to allow the passage of a fetus"epididymis - a convoluted tubule in each testis; carries sperm to vas deferensductus deferens, vas deferens - a duct that carries spermatozoa from the epididymis to the ejaculatory ductseminal duct - the efferent duct of the testis in manejaculatory duct - a part of the seminal duct formed by the duct from the seminal vesicle and the vas deferens; passes through the prostate glandcartilaginous tube - a duct with cartilaginous wallsbronchiole - any of the smallest bronchial ducts; ending in alveolialimentary canal, alimentary tract, digestive tract, digestive tube, gastrointestinal tract, GI tract - tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and eliminationlactiferous duct - ducts of the mammary gland that carry milk to the nipple
	7.	channel - a television station and its programs; "a satellite TV channel"; "surfing through the channels"; "they offer more than one hundred channels"television channel, TV channeltelevision station, TV station - station for the production and transmission of television broadcasts
	8.	channel - a way of selling a company's product either directly or via distributors; "possible distribution channels are wholesalers or small retailers or retail chains or direct mailers or your own stores"distribution channelmarketing - the commercial processes involved in promoting and selling and distributing a product or service; "most companies have a manager in charge of marketing"
Verb	1.	channel - transmit or serve as the medium for transmission; "Sound carries well over water"; "The airwaves carry the sound"; "Many metals conduct heat"transmit, impart, carry, conduct, conveyconvey, express, carry - serve as a means for expressing something; "The painting of Mary carries motherly love"; "His voice carried a lot of anger"bring, convey, take - take something or somebody with oneself somewhere; "Bring me the box from the other room"; "Take these letters to the boss"; "This brings me to the main point"wash up - carry somewhere (of water or current or waves); "The tide washed up the corpse"pipe in - bring in through pipes; "Music was piped into the offices"bring in - transmit; "The microphone brought in the sounds from the room next to mine"retransmit - transmit againcarry - be conveyed over a certain distance; "Her voice carries very well in this big opera house"
	2.	channel - direct the flow of; "channel information towards a broad audience"canalise, canalizechannelise, channelize, guide, maneuver, steer, manoeuver, manoeuvre, point, head, direct - direct the course; determine the direction of travelling
	3.	channel - send from one person or place to another; "transmit a message"channelise, channelize, transmit, transport, transferfetch, bring, get, convey - go or come after and bring or take back; "Get me those books over there, please"; "Could you bring the wine?"; "The dog fetched the hat"project - transfer (ideas or principles) from one domain into anotherpropagate - transmit; "propagate sound or light through air"translate - bring to a certain spiritual staterelease, turn - let (something) fall or spill from a container; "turn the flour onto a plate"send out, send - to cause or order to be taken, directed, or transmitted to another place; "He had sent the dispatches downtown to the proper people and had slept"move, displace - cause to move or shift into a new position or place, both in a concrete and in an abstract sense; "Move those boxes into the corner, please"; "I'm moving my money to another bank"; "The director moved more responsibilities onto his new assistant"

channel

noun1. means, way, course, approach, medium, route, path, avenue We'll be lodging a complaint through the official channels.2. strait, sound, route, passage, canal, waterway, main Oil spilled into the channel following a collision between a tanker and a trawler.3. duct, chamber, artery, groove, gutter, furrow, conduit Keep the drainage channel clear.verb1. direct, guide, conduct, transmit, convey Stephen is channelling all his energies into his novel.

channel

verb1. To direct toward a common center:center, concentrate, converge, focalize, focus.2. To serve as a conduit:carry, conduct, convey, transmit.

Translations

频道开辟水道引导水道沟渠

channel

(ˈtʃӕnl) noun1. the bed of a stream or other way through which liquid can flow. a sewage channel.沟渠2. a passage of deeper water in a river, through which ships can sail. 水道3. a narrow stretch of water joining two seas. the English Channel.海峡4. a means of sending or receiving information etc. We got the information through the usual channels.途径5. (in television, radio etc) a band of frequencies for sending or receiving signals. BBC Television now has two channels.频道 verb – past tense, past participle ˈchannelled , (American) ˈchanneled – 1. to make a channel in. 开辟水道2. to direct into a particular course. He channelled all his energies into the project.引导

channel

→ 频道zhCN

Channel

channel

¹1. a broad strait connecting two areas of sea 2. the bed or course of a river, stream, or canal 3. a navigable course through a body of water 4. Electronicsa. a band of radio frequencies assigned for a particular purpose, esp the broadcasting of a television signal b. a path for an electromagnetic signal c. a thin semiconductor layer between the source and drain of a field-effect transistor, the conductance of which is controlled by the gate voltage 5. a groove or flute, as in the shaft of a column 6. Computinga. a path along which data can be transmitted between a central processing unit and one or more peripheral devices b. one of the lines along the length of a paper tape on which information can be stored in the form of punched holes

channel

² Nautical a flat timber or metal ledge projecting from the hull of a vessel above the chainplates to increase the angle of the shrouds

Channel

the. short for English Channel

Channel

A rolled iron or steel or extruded aluminum shape with a vertical flange and horizontal top and bottom webs that project on the same side as the flange.

Channel

(information channel). (1) The set of devices connecting communications lines, for receiving, transmitting, converting, and recording information. The initial and terminal devices may be telephones or telegraphs, tape recorders, punchers, computers, lasers, or acoustical devices. In communications, use is ordinarily made of radio channels, acoustical and optical communications lines, signal cable, wires, and telephone, telegraph, and radio relay lines. The technical characteristics of a channel are determined by the operating principle of the devices included in it, the type of signal, the properties and composition of the physical media in which the electrical, acoustic, and light signals are propagated, and the properties of the code or language being used. The effectiveness of channels is characterized by the speed and reliability of information transmission, the reliability of operation of the devices, and the time delay of signals.

(2) The aggregate of digital computer devices directly involved in the reception, storage, processing, and readout of information.

REFERENCES

Goldman, S. Teoriia informatsii. Moscow, 1957. (Translated from English.)
Shannon, C. Raboty po teorii informatsii i kibernetiki. Moscow, 1963. (Translated from English.)

E. IA. DASHEVSKII

Channel

in information theory, any device for transmitting information. Unlike engineering, information theory abstracts from the concrete nature of these devices, much as geometry studies the volumes of bodies in abstraction from the material of which they are made. In information theory specific communications systems are considered only from the point of view of the amount of information that can be transmitted reliably using them.

The concept of the channel is approached in the following way: the channel is defined by the set of “permissible” messages (or signals) x at the input, the set of messages (signals) y at the output, and the set of conditional probabilities p( y|x) of receiving signal y at the output with input signal x. The conditional probabilities p(y|x) describe the statistical property of the “noise” (interference) that distorts signals during the transmission process. If p(y|x) = 1 for y = x and p(y|x) = 0 for y≠ x, the channel is called a channel without noise.

A distinction is made between discrete and continuous channels in accordance with the structure of input and output signals. In discrete channels signals at the input and output are sequences of “letters” from one and the same or different “alphabets” (codes). In continuous channels the input and output signals are functions of the continuous parameter t —time. Mixed cases are also possible, but it is usually preferred to consider one of the two cases as an idealization.

The ability of a channel to transmit information is characterized by a certain number—the carrying capacity, or simply capacity, of the channel. It is defined as the maximum amount of information relative to a signal at the input contained in a signal at the output (calculated per unit of time).

To be more precise, suppose that input signal ξ assumes several values x with probabilities p(x). Then according to probability theory, the probabilities q(y) that signal η will assume the value y at the output can be calculated by the formula

just as probabilities p( x, y) that events ξ = x and η= y will coincide can be determined by

p(x, y) = p(x)p(y|x)

The last formula is used to compute the amount of information (in binary units) I(η, ξ)= I(ξ;, η) and its average value

where T is the duration of ξ. The upper limit C of magnitudes R, taken for all permissible signals at the input, is called the channel capacity. Computing capacity, like computing entropy, is easier in the discrete case and significantly more complex in the continuous case, where it is based on the theory of stationary random processes.

Simplest of all is the case of a discrete channel without noise. Information theory establishes that in this case the general definition of capacity C is equivalent to the following:

where N(T) is the number of permissible signals of duration T.

Example 1. Suppose the “alphabet” of the channel without noise consists of two “letters,” 0 and 1, with a duration of T seconds each. Permissible signals of duration T = nT are represented by a sequence of the symbols 0 and 1. Their number is N(T) = 2ⁿ. Accordingly,

Example 2. Suppose that symbols 0 and 1 have durations of T and 2T seconds, respectively. In this case there will be fewer permissible signals of duration T = nT than in Example 1. For example, where n = 3 there will be only three (instead of eight). Now we may calculate

When it is necessary to transmit on a given channel messages written using a certain code, these messages must be converted into permissible signals in the channel, that is, the appropriate encoding must be carried out. After transmission the decoding operation must be performed, that is, the inverse operation of converting the signal back into the message. Naturally it is advisable to do the encoding so that the average time spent on transmission is minimal. Where the duration of symbols at the channel input is identical, this means that one must select the most economical code with an “alphabet” that coincides with the input “alphabet” of the channel.

When the procedure for matching the source with the channel as described above is used, the phenomenon of delay occurs. This may be clarified by Example 3.

Example 3. Suppose that a message source sends independent symbols that assume the values x₁, x₂, x₃, and x₄ with probabilities equal to, respectively, 1/2, 1/4, 1/8, and 1/8 at time intervals of 1/v (that is, with a speed of v). Assume that the channel is without noise, as in Example 1, and that coding is done instantaneously. The signal received is either transmitted on the channel if it is free or it waits (is placed in “memory”) until the channel is free. Now if, for example, we have selected the code x₁ = 00, x₂ = 01, x₃ = 10, x₄ = 11 and v ≤ (1/2)T (that is, 1/v ≥ 2 T), then in the time between the appearance of two sequential values of x it will be possible to transmit the coded notation, and the channel will be free. Thus, in this case the time interval 2T passes between the appearance of some message “letter” and transmission of its coded notation along the channel. Where v > (l/2)T, a different result is observed: the «th “letter” of the message appears at the moment (n — l)/v and its coded notation will be transmitted along the channel at moment 2nT. Therefore, the time interval between the appearance of the nth “letter” of the message and the moment of its appearance after decoding of the transmitted signal will be greater than n(2T — 1/v), which approaches infinity as n → ∞ oo. Thus, in this case the transmission will be carried on with unlimited delay. Therefore, to be able to transmit without unlimited delay for the given code, satisfaction of the inequality is necessary and sufficient. Selection of a better code can increase transmission speed by making it as close as one wants to the capacity of the channel, but this limit cannot be exceeded (needless to say, while preserving the requirement that delay is limited). This statement is completely general and is called the fundamental theorem of channels without noise.

It is relevant to add the following note in special relation to Example 3. For the messages considered, the binary code x₁ = 0, x₂ = 10, x₃ = 110, and x₄ = 111 is optimal. Because of the different lengths of the coded notations, delay time w_n for the nth. “letter” of the initial message will be a random variable. When v < 1/T (1/T—channel capacity) and n→∞, its average value approaches a certain limit m(v ), which depends on v. As v approaches the critical value 1/r, the value of m(v ) increases in proportion to (T⁻¹— v)⁻¹. This once again reflects the general proposition that the endeavor to make transmission speed as close to maximal as possible involves an increase in delay time and in the necessary size of the “memory” of the coding device.

The assertion of the fundamental theorem (substituting “almost error-free” for error-free transmission) also applies to channels with noise. This fact, which is truly fundamental for the entire theory of information transmission, is called Shannon’s theorem. The possibility of reducing the probability of erroneous transmission through channels with noise is achieved by using so-called noise-combating codes.

Example 4. Suppose that the input “alphabet” of the channel consists of two symbols 0 and 1 and the noise effect is expressed as follows: during transmission each of the symbols may with a slight (for example, equal to 1/10) probability p change into the other or, with a probability of q = 1 — p, remain undistorted. The use of a noise-combating code essentially amounts to selecting a new “alphabet” at the input of the channel. Its “letters” are ^-element chains of the symbols 0 and 1 that differ from one another by a sufficient number of characters D. Thus, where n = 5 and nD = 3 the new “letters” can be 00000, 01110, 10101, and 11011. If the probability of more than one error for a group of five characters is small, then even when distorted these new “letters” can hardly be confused. For example, if the signal 10001 is received, it almost certainly came from 10101.

It turns out that with a proper selection of sufficiently large n and D this method is significantly more effective than simple repetition (that is, using “alphabets” of the 000, 111 type). However, possible improvement of the transmission process in this way inevitably involves greatly increasing the complexity of the coding and decoding devices. For example, it has been calculated that if p = 10⁻² initially and this value must be decreased to P¹= 10 ⁻⁴, then the length of the code chain n must be selected not less than 25 (or 380) depending on whether the channel capacity to be used is 53 percent (or 80 percent).

IU. V. PROKHOROV

Channel

(1) A short natural passageway that links such water basins as lakes or a lake with a river. Less frequently, it links two rivers or a river with a lake.

(2) A river’s secondary watercourse when it is divided by islands into several branches.

Channel

the part of a valley floor where a body of water flows. The channels of large rivers range in width from a few meters to tens of kilometers, for example, the lower courses of the Ob’, Lena, and Amazon. As river size increases, the increase in channel depth is less than the increase in width, according approximately to the relation here h is the average depth, A is a coefficient dependent on the character of the soils, and b is the average width. Along the length of a channel, deep spots (pools) alternate with shallow stretches (shoals). The channels of lowland rivers are usually winding or divided into arms and may be formed in muddy, sandy, or gravelly deposits. The channels of mountain rivers are straighter, often have rapids and waterfalls, and usually contain large boulders.

Channel

a beam or strip, usually made of metal, with a squared-off, U-shaped cross section, with a height of 50–400 mm and a wall thickness of 4–15 mm. Steel channels are produced primarily by hot rolling billets in section mills (seeROLLED SECTION). Channels with thin flanges are produced on section-bending machines; those made of nonferrous metals are usually manufactured by extrusion through a shaped slot. Several dozen shapes and sizes of channels are produced. They are primarily used in construction.

channel

[′chan·əl] (chemical engineering) In percolation filtration, a portion of the clay bed where there is a preponderance of flow. (civil engineering) A natural or artificial waterway connecting two bodies of water or containing moving water. (communications) A band of radio frequencies allocated for a particular purpose; a standard broadcasting channel is 10 kilohertz wide, a television channel 6 megahertz wide. A path through which electrical transmission of information takes place. (computer science) A path along which digital or other information may flow in a computer. The section of a storage medium that is accessible to a given reading station in a computer, such as a path parallel to the edge of a magnetic tape or drum or a path in a delay-line memory. One of the longitudinal rows of intelligence holes punched along the length of paper tape. Also known as level. A device or portion of a computer that controls and stores data and transfers information between the computer and peripheral equipment. (electronics) A path for a signal, as an audio amplifier may have several input channels. The main current path between the source and drain electrodes in a field-effect transistor or other semiconductor device. (engineering) The forming of cavities in a gear lubricant at low temperatures because of congealing. (hydrology) The deeper portion of a waterway carrying the main current. (navigation) Navigable portion of a body of water. (nucleonics) A passage for fuel slugs or heat-transfer fluid in a reactor. (petroleum engineering) In a drilling operation, a cavity appearing behind the casing because of a defect in the cement.

channel

channel, 1 1. A structural or rolled steel shape used in steel construction. 2. A decorative groove, in carpentry or masonry. 3. An enclosure containing the ballast, starter, lamp holders, and wiring for a fluorescent lamp, or a similar enclosure on which filament lamps (usually tubular) are mounted.

channel (ch)

As it refers to radio, it is the single means of direct fixed-service communication between two points. A radio usually has more than one channel.

channel

(chat)(Or "chat room", "room", depending on the system inquestion) The basic unit of group discussion in chat systemslike IRC. Once one joins a channel, everything one types isread by others on that channel. Channels can either be namedwith numbers or with strings that begin with a "#" sign andcan have topic descriptions (which are generally irrelevant tothe actual subject of discussion).

Some notable channels are "#initgame", "#hottub" and"#report". At times of international crisis, "#report" hashundreds of members, some of whom take turns listening tovarious news services and typing in summaries of the news, orin some cases, giving first-hand accounts of the action(e.g. Scud missile attacks in Tel Aviv during the Gulf War in1991).

channel

(1) The distribution of IT products through independent sales organizations. The manufacturer sells its products either directly to IT resellers (the dealers), which are the point of contact with the customer, or they sell to an IT distributor organization that sells to the dealers. Manufacturers that sell in the channel rely on the sales ability of the dealers and the customer relationships they have built up over the years. Sometimes, manufacturers also compete with the channel by selling directly to the customer via catalogs and the Web.

(2) A high-speed mainframe subsystem that provides a pathway between the CPU and the control units of peripheral devices. Each channel is an independent unit that transfers data concurrently with other channels. In contrast, the PCI bus in a desktop computer is shared among all attached devices. See mainframe and PCI.

(3) The physical connecting medium between devices in a network; for example, twisted wire pairs, coaxial cable and optical fibers.

(4) A frequency assigned to a TV or radio station, which allows it to transmit over the air simultaneously with other broadcasters. See carrier.

(5) See alpha channel.

channel

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chan•nel1

chan•nel2

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channel surf

channel surfing

(all) great minds run in the same channel

change the channel

channel (something) in(to) (something)

channel (something) off

go through (the proper) channels

channel-hopping

channel-surfing

channel surfer

channel-zapping

change the channel

channel something in

channel something off

go through (the proper) channels

work through channels

channel surfing

go through channels

great minds run in the same channel, all

change the channel

channel hopping

channel surfing

channel zapping

channel surfer

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Synonyms for channel

noun means

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noun strait

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noun duct

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verb direct

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Synonyms for channel

verb to direct toward a common center

Synonyms

verb to serve as a conduit

Synonyms

Synonyms for channel

chan·nel¹

chan·nel²

chan•nel¹

chan•nel²