# Designing priority encoder with 4-16 decoder and 8-1 MUX

Tags:
1. Dec 24, 2014

### Kurokari

1. The problem statement, all variables and given/known data
Design a 4 input priority encoder with a 4 to 16 decoder and a 8 to 1 multiplexer.

2. Relevant equations
Priority encoder is where when the highest priority bit is equal to a logical "1", then the rest of the lower priority input are ignored.

3. The attempt at a solution

For the MUX design, since we can only use a 8 to 1 MUX, means we'll have to use at least 2 of them. But I'm not very sure on how to relate the 2 outputs into one.

For the decoder design, I'm just confused. Shouldn't a priority encoder be a encoder, while a decoder is used to decode input? Is it possible that the question I have meant something else but a decoder?

2. Dec 29, 2014

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Jan 2, 2015

### haruspex

The end result will be a 2 bit output, yes? That fits with needing two single bit output multiexers.
Each multiplexer would need (in principle) 11 inputs, no?
As for encoder versus decoder, the distinction is a bit artificial. I guess that decoders typically arrange that no two different inputs vectors produce the same output, whereas encoders typically cannot do that.