Encoder and Decoder
What is Encoder?
An Encoder is a device that is used to change a signal (such as bitstream) or data into a code. The code may serve any of a number of purposes such as compressing information for transmission or storage, encrypting or adding redundancies to the input code, or translating from one code to another. Encoders perform a reverse operation from the decoder. So, an encoder will have 2n input lines that will be used to generate maximum of n output lines. If a device output code has fewer bits than the input code has, the device is usually called an encoder.
There are Four types of Encoder
- Priority encoder.
- Decimal to BCD encoder.
- Octal to Binary encoder.
- Hexadecimal to Binary encoder.
Two popular Encoder ICs
A popular example of an Encoder is the Holtek Encoder H12E used for parallel to serial conversion.
Another popular example of Encoder IC used as a priority Encoder is HC148 which is an 8 to 3 Line Priority Encoder.
What is Decoder?
A decoder is a combinational circuit that converts a binary input of n variable into maximum of 2n unique output variables. Decoder can detect a code and activate a single output to signal the presence of that code. Block diagram to represent 3-to-8 decoder is given below-
Decoder have many applications, from producing system alerts in alarm systems to performing the task of driving multiple devices in microprocessor system (e.g. memory).