Decoder
Decoder may refer to a device, process, or concept that decodes or interprets information, with applications in various fields. In technology, it commonly denotes components such as binary decoders, instruction decoders, codecs, and neural network decoders in artificial intelligence. In music, it may refer to recording artists or groups. Other uses include works in film and novelty items.Technology
Binary Decoder
A binary decoder is a combinational logic circuit that converts an n-bit binary input code into one of 2^n possible output lines, activating exactly one output corresponding to the input value while deactivating the others.[1] This one-hot encoding ensures unique selection without reliance on prior states, making it ideal for static signal routing and decoding tasks in digital systems.[2] Binary decoders come in several types tailored to specific needs. The fundamental 1-of-2^n decoder, such as a 3-to-8 variant, directly maps n inputs to 2^n outputs for general-purpose selection.[1] BCD-to-7-segment decoders, by contrast, interpret 4-bit binary-coded decimal inputs and generate signals to drive seven-segment displays, treating invalid BCD codes (10-15) as don't-cares for simplification.[1] For scalability, cascaded decoders combine smaller units hierarchically; for instance, four 3-to-8 decoders can form a 5-to-32 decoder by using the higher-order 2 bits to select among the four lower-order 3-to-8 blocks.[1] Implementation typically employs AND gates for output generation and NOT gates for input inversion, with an optional enable input to control activation.[2] Design begins with a truth table listing all input combinations and corresponding outputs, followed by Boolean minimization using Karnaugh maps to reduce gate count.[1] A classic example is the 2-to-4 decoder with inputs A (MSB) and B (LSB), whose truth table is:| A | B | Y₀ | Y₁ | Y₂ | Y₃ |
|---|---|---|---|---|---|
| 0 | 0 | 1 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 | 0 | 0 |
| 1 | 0 | 0 | 0 | 1 | 0 |
| 1 | 1 | 0 | 0 | 0 | 1 |