Decoder (redirected from Decoders)

decoder

A hardware device or software that converts coded data back into its original form. See decode and MPEG decoder.

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decoder [dē′kōd·ər]

(communications)

A device that decodes.

(electronics)

A matrix of logic elements that selects one or more output channels, depending on the combination of input signals present.

decoder circuit matrix tree

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Decoder 

code translator, in computer technology, an assembly of computer component elements in which a coded input combination is converted into a signal at one of the outputs.

The most common decoders are the binary code translators, used for decoding op codes, instruction codes, addresses, and so on. In a digital computer the decoder is built so that when a number in multibit binary code arrives at its input the signal “1” appears at the corresponding output and the signal “0” appears at the remaining outputs. Binary decoders are constructed on the basis of coincidence logic circuits. The structure of the decoder may be matrix, pyramidal, or stepped. The matrix decoder uses multi-input coincidence circuits; pyramidal decoders use two-input circuits; stepped decoders use a particular set of multi-input and two-input coincidence circuits. Decoders function on diodes, transistors, or magnetic elements, as well as on combinations of these; decoders built on diode coincidence circuits are widespread.

REFERENCE

Gol’denberg, L. M.. Teoriia i raschet impul’snykh ustroistv na poluprovodnikovykh priborakh. Moscow, 1969.

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Decoder 

in general use, a device for decoding a message and translating the information it contains into the language (code) of the receiving system.

In the general case the decoder has n inputs and m outputs. Information arriving at the inputs of the decoder is converted—decoded—and a signal indicating the sign (or content) of the raw information appears at the appropriate output (or group of outputs). There is a definite signal or combination of signals at the decoder outputs to correspond to any signal or combination of signals at the inputs. This correspondence is determined by the structure assigned during designing of the decoder. Decoders are used in various data processing and transmitting devices: in remote control, in computer technology (code translators, data converters), in radio engineering and measurement techniques (detectors, demodulators), and in telephone and telegraph communications systems. The purpose determines the structure and the number of inputs and outputs of the decoder and the form and sequence of the input and output signals.

In remote control operations decoders decode messages (their codes) according to the structure of the signals received. The structure of the signals is created by assigning different features—signs—to the pulses that form the signals. The polarity, frequency, order, number, length, and amplitude of the pulses and the grouping of pulses of different types are such signs. For example, if the decoder is being used in a remote control system, the decoder automatically analyzes the structure of the signals received in accordance with a program built into the design of the decoder itself; signals from its outputs are fed to the inputs of the actuating mechanisms of the objects being controlled. Selectivity is a basic property of the decoder; it ensures that the input circuits of the receiving systems are protected against outside signals (which could give false input to the system).

In computer technology decoders are used for converting a code or codes into equivalent continuous quantities (for example, electrical current, voltage, angle of rotation). In radio engineering, decoders reconstruct the message transmitted from a radio signal whose parameters (amplitude, frequency, phase) change according to the message being transmitted.

REFERENCE

Tutevich, V. N. Osnovy telemekhaniki. Moscow-Leningrad, 1967.

M. M. GEL’MAN