counter

Dictionary: coun·ter¹ (koun'tər) pronunciation

adj.
Contrary; opposing: moves and counter moves on the checkerboard.

n.

One that is an opposite.
Sports. A boxing blow given while receiving or parrying another.
Sports. A fencing parry in which one foil follows the other in a circular fashion.
A stiff piece of leather around the heel of a shoe.
Nautical. The portion of a ship's stern extending from the water line to the extreme outward swell.
Printing. The depression between the raised lines of the face on a piece of type.

v., -tered, -ter·ing, -ters.

v.tr.

To meet or return (a blow) by another blow.
To move or act in opposition to; oppose.
To offer in response: countered that she was too busy to be thorough.

v.intr.
To move, act, or respond so as to be in opposition.

adv.

In a contrary manner or direction.
To or toward an opposite or dissimilar course or outcome: a method running counter to traditional techniques.

[Middle English countre, from Old French contre, from Latin contrā. See counter-.]

count·er² (koun'tər) pronunciation

A flat surface on which money is counted, business is transacted, or food is prepared or served.
Games. A piece, as of wood or ivory, used for keeping a count or a place.
1. An imitation coin; a token.
2. A piece of money.

idioms:

over the counter

Without being listed or available on an officially recognized stock exchange but traded in direct negotiation between buyers and sellers: bought stocks over the counter.
Without a doctor's prescription being legally required: cold medicine that is available over the counter.

under the counter

In an illegal or surreptitious manner; illicitly: arrested for selling prescription drugs under the counter.

[Middle English countour, from Anglo-Norman counteour, from Medieval Latin computātōrium, countinghouse, from Latin computāre, to calculate. See count¹.]

count·er³ (koun'tər) pronunciation

n.
One that counts, especially an electronic or mechanical device that automatically counts occurrences or repetitions of phenomena or events.

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Computer Desktop Encyclopedia: counter

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(1) In programming, a variable that is used to keep track of anything that must be counted. The programming language determines the number of counters (variables) that are available to a programmer.

(2) In electronics, a circuit that counts pulses and generates an output at a specified time.

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Thesaurus: counter

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adjective

See

noun

Logic

verb

To return like for like, especially to return an unfriendly or hostile action with a similar one: hit back, reciprocate, retaliate, retort, strike back. See attack/defend, forgiveness/vindictiveness.
To place in opposition or be in opposition to: match, oppose, pit, play off. Idioms: bump heads with, meet head-on, setbeat odds, setbeat someone's throat, tradeblowspunches. See support/oppose.

Antonyms: counter

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adj

Definition: opposite, opposing
Antonyms: agreeing, concurring, corresponding, corroborating, equal, same, similar

adv

Definition: contrary, reverse
Antonyms: equally, same, similarly

Dental Dictionary: counter

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A device for enumerating ionizing events.

US Military Dictionary: counter

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n. the curved part of the stern of a ship projecting aft above the waterline.

See the Introduction, Abbreviations and Pronunciation for further details.

Architecture: counter

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1. A long horizontal surface used in stores, shops, banks, etc., for display of goods, for work-top areas, or for business transactions.
2. The top or working surface of the base of a kitchen cabinet.

Veterinary Dictionary: counter

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An instrument or apparatus by which numerical value is computed; in radiology, a device for enumerating ionizing events.

Coulter c. — see coulter counter.
Geiger c., Geiger–Müller c. — a radiation counter using a gas-filled tube that indicates the presence of ionizing particles.
scintillation c. — a device for detecting beta and gamma rays, permitting determination of the concentration of radioisotopes in the body or other substance. It is more important for gamma rays, which are poorly measured by a Geiger counter.

Word Tutor: counter

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IN BRIEF: n. - A piece of furniture that stands at the side of a dining room; Table consisting of a horizontal surface over which business is transacted; Also: In the opposite direction; In opposition; contrary.

Theories that go counter to the facts of human nature are foredoomed. — Edith Hamilton

Wikipedia: Counter

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This article is about the term counter used in electronics and computing. For other uses, see Counter (disambiguation).

In digital logic and computing, a counter is a device which stores (and sometimes displays) the number of times a particular event or process has occurred, often in relationship to a clock signal. In practice, there are two types of counters:

Up counters, which increase (increment) in value
Down counters, which decrease (decrement) in value

1 In electronics
2 In computer science
3 Mechanical counters
4 References
5 See also

In electronics

Toggle flip-flop. Output is not shown. Red=1, blue=0

In electronics, counters can be implemented quite easily using register-type circuits such as the flip-flop, and a wide variety of designs exist, e.g:

Asynchronous (ripple) counter – changing state bits are used as clocks to subsequent state flip-flops
Synchronous counter – all state bits change under control of a single clock
Decade counter – counts through ten states per stage
Up–down counter – counts both up and down, under command of a control input
Ring counter – formed by a shift register with feedback connection in a ring
Johnson counter – a twisted ring counter
Cascaded counter

Each is useful for different applications. Usually, counter circuits are digital in nature, and count in natural binary. Many types of counter circuit are available as digital building blocks, for example a number of chips in the 4000 series implement different counters.

Occasionally there are advantages to using a counting sequence other than the natural binary sequence -- such as the binary coded decimal counter, a linear feedback shift register counter, or a Gray-code counter.

Asynchronous (ripple) counter

Asynchronous counter created from JK flip-flops

The hfn simplest counter circuit is a single D-type flip-flop, with its D (data) input fed from its own inverted output. This circuit can store one bit, and hence can count from zero to one before it overflows (starts over from 0). This counter will increment once for every clock cycle and takes two clock cycles to overflow, so every cycle it will alternate between a transition from 0 to 1 and a transition from 1 to 0. Notice that this creates a new clock with a 50% duty cycle at exactly half the frequency of the input clock. If this output is then used as the clock signal for a similarly arranged D flip-flop (remembering to invert the output to the input), you will get another 1 bit counter that counts half as fast. Putting them together yields a two bit counter:

Cycle	Q1	Q0	(Q1:Q0)dec
0	0	0	0
1	0	1	1
2	1	0	2
3	1	1	3
4	0	0	0

You can continue to add additional flip-flops, always inverting the output to its own input, and using the output from the previous flip-flop as the clock signal. The result is called a ripple counter, which can count to 2ⁿ-1 where n is the number of bits (flip-flop stages) in the counter. Ripple counters suffer from unstable outputs as the overflows "ripple" from stage to stage, but they do find frequent application as dividers for clock signals, where the instantaneous count is unimportant, but the division ratio overall is. (To clarify this, a 1-bit counter is exactly equivalent to a divide by two circuit; the output frequency is exactly half that of the input when fed with a regular train of clock pulses).

The use of flip-flop outputs as clocks leads to timing skew between the count data bits, making this ripple technique incompatible with normal synchronous circuit design styles.

Synchronous counter

A 4-bit synchronous counter using J-K flip-flops

Where a stable count value is important across several bits, which is the case in most counter systems, synchronous counters are used. These also use flip-flops, either the D-type or the more complex J-K type, but here, each stage is clocked simultaneously by a common clock signal. Logic gates between each stage of the circuit control data flow from stage to stage so that the desired count behavior is realized. Synchronous counters can be designed to count up or down, or both according to a direction input, and may be presetable via a set of parallel "jam" inputs. Most hardware-based counters are of this type.

A simple way of implementing the logic for each bit of an ascending counter (which is what is depicted in the image to the right) is for each bit to toggle when all of the less significant bits are at a logic high state. For example, bit 1 toggles when bit 0 is logic high; bit 2 toggles when both bit 1 and bit 0 are logic high; bit 3 toggles when bit 2, bit 1 and bit 0 are all high; and so on.

Synchronous counters can also be implemented with hardware finite state machines, which are more complex but allow for smoother, more stable transitions.

Please note that the counter shown will have an error once it reaches 1110.

Ring counter

Main article: Ring counter

A ring counter is a shift register (a cascade connection of flip-flops) with the output of the last one connected to the input of the first, that is, in a ring. Typically a pattern consisting of a single 1 bit is circulated, so the state repeats every N clock cycles if N flip-flops are used. It can be used as a cycle counter of N states.

Johnson counter

A Johnson counter (or switchtail ring counter, twisted-ring counter, walking-ring counter, or Moebius counter) is a modified ring counter, where the output from the last stage is inverted and fed back as input to the first stage.^[1]^[2]^[3] A pattern of bits equal in length to twice the length of the shift register thus circulates indefinitely. These counters find specialist applications, including those similar to the decade counter, digital to analog conversion, etc.

Decade counter

A decade counter is one that counts in decimal digits, rather than binary. A decimal counter may have each digit binary encoded (that is, it may count in binary-coded decimal, as the 7490 integrated circuit did) or other binary encodings (such as the bi-quinary encoding of the 7490 integrated circuit). Alternatively, it may have a "fully decoded" or one-hot output code in which each output goes high in turn; the 4017 was such a circuit. The latter type of circuit finds applications in multiplexers and demultiplexers, or wherever a scanning type of behaviour is useful. Similar counters with different numbers of outputs are also common.

The decade counter is also known as a mod-10 counter.

Up–down counter

A counter that can change state in either direction, under control an up–down selector input, is known as an up–down counter. When the selector is in the up state, the counter increments its value; when the selector is in the down state, the counter decrements the count.

In computer science

Main article: Register machine

In computability theory, a counter is considered a type of memory. A counter stores a single natural number (initially zero) and can be arbitrarily many digits long. A counter is usually considered in conjunction with a finite state machine (FSM), which can perform the following operations on the counter:

Check whether the counter is zero
Increment the counter by one
Decrement the counter by one (if it's already zero, this leaves it unchanged).

The following machines are listed in order of power, with each one being strictly more powerful than the one below it:

Deterministic or non-deterministic FSM plus two counters
Non-deterministic FSM plus one stack
Non-deterministic FSM plus one counter
Deterministic FSM plus one counter
Deterministic or non-deterministic FSM

For the first and last, it doesn't matter whether the FSM is deterministic or non-deterministic (see determinism). They have equivalent power. The first two and the last one are levels of the Chomsky hierarchy.

The first machine, an FSM plus two counters, is equivalent in power to a Turing machine. See the article on register machines for a proof.

Mechanical counters

Mechanical counter wheels showing both sides. The bump on the wheel shown at the top engages the ratchet on the wheel below every turn.

Several mechanical counters

Long before electronics became common, mechanical devices were used to count events. These typically consist of a series of disks mounted on an axle, with the digits 0 through 9 marked on their edge. The right most disk moves one increment with each event. Each disk except the left-most has a protrusion that, after the completion of one revolution, moves the next disk to the left one increment. Such counters were originally used to control manufacturing processes, but were later used as odometers for bicycles and cars and in fuel dispensers. One of the largest manufacturers was the Veeder-Root company, and their name was often used for this type of counter.^[4]

Wikimedia Commons has media related to: mechanical counters

References

^ Arun Kumar Singh. Digital Principles Foundation of Circuit Design and Application. New Age Publishers. ISBN 8122417590. http://books.google.com/books?id=13Wi37h2A-oC&pg=PA113&dq=switchtail+ring+counter+johnson&as_brr=3&ei=umTxSPXeKZH2sQP6muHZBg&sig=ACfU3U29vJPSflqg7sngLSbt5OxDp6fMvQ.
^ Paul Horowitz and Winfield Hill (1989). The Art of Electronics. Cambridge University Press. ISBN 0521370957. http://books.google.com/books?id=bkOMDgwFA28C&pg=PA667&dq=ring+counter+walking&as_brr=3&ei=NGbxSLrfIIuoswP_oqmdBw&sig=ACfU3U0nWT1AwZt_wgUnAedWxa8X6iDktw.
^ Rudolf F. Graf (1999). Modern Dictionary of Electronics. Newnes. ISBN 0750698667. http://books.google.com/books?id=uah1PkxWeKYC&pg=PA401&dq=moebius+ring+counter+johnson&as_brr=3&ei=z2bxSO3hN4XWsgOa243rBg&sig=ACfU3U38T_bIIfEQqOjEIxVzFKp8_oyd6w.
^ http://www.veeder.com/page/vr_history

Ελληνική (Greek)
v. - αντισταθμίζω, εξουδετερώνω, αντιμάχομαι, καταπολεμώ, ανταπαντώ, ανταποδίδω
n. - μετρητής, αριθμητής, καταμετρητής, όργανο μέτρησης, κοντέρ, φίσα, μάρκα (χαρτοπαιξίας κ.λπ.), πάγκος πωλήσεων, θυρίδα ή γκισέ τράπεζας
pref. - αντι-, ανθ(υ)-, διπλο-, επ(ανα)-, ξανα-, παρα-

idioms:

counter espionage αντικατασκοπία
counter to αντίθετα από, αντίθετος προς, εχθρικός σε
over the counter στα φανερά, ανοιχτά, (οικον.) στην εξωχρηματιστηριακή αγορά

Italiano (Italian)
smentire, ribattere, reagire, sportello, contatore, gettone, banco

idioms:

counter espionage controspionaggio
counter to contrariamente a
over the counter in vendita libera, senza bisogno di ricetta medica
rev counter contagiri

Português (Portuguese)
v. - opor-se
n. - contador (m), mostrador (m)
pref. - contra

idioms:

counter espionage contra-espionagem (f)
counter to contrário a
Geiger counter contador (m) Geiger
over the counter no balcão
rev counter contador (m) de revoluções, conta-giros (m) (Téc.)
under the counter ilegalmente

Русский (Russian)
противодействовать, парировать, окошко, прилавок, счетчик, фишка

idioms:

counter espionage контрразведка
counter to вопреки
Geiger counter счетчик Гейгера
over the counter без рецепта
rev counter тахометр
under the counter из-под прилавка

Español (Spanish)
1.
n. - ventanilla, taquilla, barra, mostrador

idioms:

behind the counter detrás del mostrador
over the counter pagar al contado, sin receta, extrabursátil

2.
v. tr. - refutar, rebatir, contrariar, contestar
v. intr. - refutarse, rebatirse, contrariarse, contestarse, medirse
adv. - contrariamente
adj. - contrario, opuesto
n. - ficha, barra, mostrador

idioms:

counter espionage contraespionaje
counter to contra, contrario a, en contra de, en conflicto con
go counter ir contra algo o alguien

3.
n. - contador, medidor

4.
n. - contrafuerte (de un zapato)

Svenska (Swedish)
v. - motsätta sig, bemöta, besvara m schackdrag, kontra
n. - räknare, räkneapparat, spelmark, pjäs, pollett, butiksdisk, expeditionslucka, arbetsbänk (am.), motsats, kontraslag (boxn.), bringa på häst, valv (sjö.), bakkappa på sko
pref. - mot-, kontra-

中文（简体）(Chinese (Simplified))
1. 相反的, 对立的, 反对的, 相反之事物, 回拳, 还击, 对立物, 主跟, 后帮, 反对, 反驳, 反击, 抵消, 反方向地, 相反地

idioms:

counter espionage 反间谍, 策反
counter to 相反地

2. 柜台, 筹码, 柜台式长桌, 伪造的硬币

idioms:

over the counter 不通过交易所直接售给顾客的

3. 计算者, 计算器, 计数器

中文（繁體）(Chinese (Traditional))
1.
n. - 計算者, 計算器, 計數器

2.
n. - 櫃檯, 籌碼, 櫃檯式長桌, 偽造的硬幣

idioms:

over the counter 不通過交易所直接售給顧客的

3.
adj. - 相反的, 對立的, 反對的
n. - 相反之事物, 回拳, 還擊, 對立物, 主跟, 後幫
v. tr. - 反對, 反駁, 反擊, 抵消
v. intr. - 反對, 反駁, 反擊, 還擊
adv. - 反方向地, 相反地

idioms:

counter espionage 反間諜, 策反
counter to 相反地

한국어 (Korean)
1.
n. - 계산대, 카운터, 위조화폐

idioms:

over the counter 카운터에 돈을 치루다, 증권업자의 가계에서

2.
v. tr. - 대항하다, 무효로 하다, 받아 치다
v. intr. - 받아 치다
adv. - 반대 방향으로, 거꾸로
adj. - 반대의 , 거꾸로의, 짝의
n. - 역 , 반대, 받아 치기

idioms:

counter to 거스르다

3.
n. - 계산하는 사람, 계산기

4.
n. - 구두의 뒤꿈치 가죽

日本語 (Japanese)
n. - 計算器, 計数器, カウンター, 数取り, 模造硬貨, 取引の材料, 利用されそうな人, 調理台, 逆, かかと革
adj. - 反対の, 命令撤回の, 片方の
v. - 逆に出る, 迎え撃つ
adv. - 反対の方向に

idioms:

bargaining counter 交渉の場, 特価品売り場
counter espionage 逆スパイ行為
counter to 逆らう
over the counter 店頭で, 小売業者を通じて

العربيه (Arabic)
‏(فعل) رد على, عارض, واجه (الاسم) عداد, طاوله البيع, فيشه قمار (بادئه الكلمه) بادئه تعني عكس أو ضد‏

עברית (Hebrew)
adj. - ‮נגדי, מנוגד, כפול, הפוך‬
n. - ‮צעד נגדי, דבר מנוגד, כיוון הפוך‬
v. tr. - ‮גמל במכה, הגיב, התנגד, אמר דבר מנוגד‬
v. intr. - ‮עשה צעד נגדי‬
adv. - ‮בניגוד, נגד, בכיוון הפוך‬
n. - ‮דלפק, דוכן, מד-, מונה, אסימון-משחק, העתק‬
n. - ‮חלק חזה הסוס שמתחת לצוואר, החלק העקום של ירכתי אוניה, חלק מוקף קווים של אות דפוס‬
n. - ‮הצד האחורי של נעל, סביב העקב‬

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counter

Contents

In electronics

Asynchronous (ripple) counter

Synchronous counter

Ring counter

Johnson counter

Decade counter

Up–down counter

In computer science

Mechanical counters

References

See also