Digital Circuits/Encoders-Decoders

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Encoders and decoders are similar to multiplexers and demultiplexers, except that they are a little bit more complicated.

Contents 1 Decoders 2 Encoders 3 Priority Encoders 4 Encoders and Multiplexors

[edit] Decoders

Decoders will have N inputs, and 2^N output. Let's say that we have two inputs (I1 and I2), and 4 outputs (O1 O2 O3 O4). Decoders will satisfy the following truth table:

I1	I2	O1	O2	O3	O4
0	0	1	0	0	0
0	1	0	1	0	0
1	0	0	0	1	0
1	1	0	0	0	1

Binary numbers come in, and essentially select which wire to send a signal on.

[edit] Encoders

Encoders work in exactly the opposite way as decoders, taking 2^N inputs, and having N outputs. When a bit comes in on an input wire, the encoder outputs the physical address of that wire.

[edit] Priority Encoders

[edit] Encoders and Multiplexors

The relationship between the two.

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