Decoder

Under a decoder or a decoder (English ) refers generally a converter, converter or transformer for analogue or digital signals. He can use a converter or an encoding, also called encoder or encoder form a logical unit or a functional sequence. A device that can generate the original input signals for the decoder output signals from the decoder, the encoder or encoder (English ).

A decoder need not necessarily have the task of fully restoring or provide another system, since the conversion of the information and signals may be redundant or lossy coding of the original information.

The following figure shows an encoder ( encoder ) / decoder (decoder ) system is:

In communication engineering, the English term decoder is used as decoder and encoder for the term encoder normally.

People and tools in cryptography to decrypt messages are often referred to as a decoder.

A distinction analog decoder, digital decoder and handovers between these two signal structures depending on the signal type.

Analog decoder

One of the common decoder for analog signals is the decoder used for the stereo reception in the VHF-FM receivers. Also for the reception of the analog color television PAL and SECAM analog decoders are used in Europe.

Digital decoder

The implementation of decoders, by a pure hardware (eg Kodeumsetzern ), pure software take place (e.g. in codecs ) or DSPs. And the digital signal processing can be used for the construction of decoders.

Digital decoder can:

  • Mechanical or electronic switches
  • Relay
  • Electron tubes
  • Diodes
  • Transistors
  • TTL chips
  • Read-only memories
  • Digital signal processors ( DSP)

Be established.

In the decoder multimedia applications and codecs are often used to reconstruct data after a transfer or compression.

Typical applications of digital decoders in the art are conversions of signals for measuring instruments, control of digital counters with different Zähllogiken and conversion of signals of parallel transmission method for serial data transmission, eg for the RS- 232 interface.

Examples of digital decoders in the circuit technology

A decoder may be a switching network, depending on implementation, of n inputs ( or less) and minimum maxterms generated. Each function can be expressed by these terms and therefore the decoder is suitable to implement any logic function by the terms occurring are linked on the output side.

For example a switching network of a digital decoder

  • Inputs: S0, S1, S2
  • Outputs: minterms M0, M1, ..., M7

1- of-n decoder

The 1- of-n decoder switches just one of n outputs to 1, where n is a power of 2, since n must be present in the binary representation of the inputs. The inputs e0, e1, e2, e3 0 1 1 0 bin = 6 dec would the output y6 = 1 and all other y0, y1, ..., y5, y7, y8, ..., y15 = 0

Using the 1-of -n decoders, for example, the individual flip-flops are selected in a memory, in which data is written by the address is applied to the inputs of the 1- of-n decoder, and the outputs Y0 ..., yn, and the flip-flop inputs F0, ..., fn are connected to an AND.

Realization of Dekodiererschaltungen with minterms / Maxtermen:

Code conversion between analog and digital

For converting analog to digital signals to analog-to- digital converter and for the reverse direction of digital -to-analog converter may be used. Major characteristics of these converters are the accuracy, linearity and speed of implementation. The main application of this decoder is the measurement technology. But even in the consumer electronics will be implemented from a CD, DVD or from a digital radio or television receiver in analog signals, eg by means of decoders digital signals.

225137
de