Encoder (digital)

<h2 id="types-of-encoder">Types of encoder</h2>
<h3>2n-to-n encoders</h3>
<p>A 
  
    
      
        
          2
          
            n
          
        
      
    
    {\displaystyle 2^{n}}
  
-to-n encoder has n number of outputs in correspondence to the 
  
    
      
        
          2
          
            n
          
        
      
    
    {\displaystyle 2^{n}}
  
 number of inputs. It thus reduces the number of transmission lines and can be compared to a <a href="/facts/Multiplexer/lVro0Sfz">multiplexer</a>. Only one of the inputs become "high" (logic state "1") at a time.
</p><p>For example, a 4-to-2 simple encoder takes 4 input bits and produces 2 output bits. The illustrated gate level example implements the simple encoder defined by the truth table, but it must be understood that for all the non-explicitly defined input combinations (i.e., inputs containing 0, 2, 3, or 4 high bits) the outputs are treated as <a href="/facts/Don%2527t-care_term/kvQuwYMK">don't cares</a>.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a>
</p>
<h4>4-to-2 encoder</h4>

Truth Table<table><tbody><tr><td colspan="4">Input</td><td colspan="3">Output</td></tr><tr><td>I3</td><td>I2</td><td>I1</td><td>I0</td><td>O1</td><td>O0</td></tr><tr><td>0</td><td>0</td><td>0</td><td>0</td><td colspan="2"><a href="/facts/Don%2527t-care_term/kvQuwYMK">x</a></td></tr><tr><td>0</td><td>0</td><td>0</td><td>1</td><td>0</td><td>0</td></tr><tr><td>0</td><td>0</td><td>1</td><td>0</td><td>0</td><td>1</td></tr><tr><td>0</td><td>1</td><td>0</td><td>0</td><td>1</td><td>0</td></tr><tr><td>1</td><td>0</td><td>0</td><td>0</td><td>1</td><td>1</td></tr></tbody></table>

<p><a href="https://en.m.wikipedia.org/wiki/Encoder_(digital)#/editor/4">https://en.m.wikipedia.org/wiki/Encoder_(digital)#/editor/4</a>
<a href="https://en.m.wikipedia.org/wiki/Encoder_(digital)#/editor/4">https://en.m.wikipedia.org/wiki/Encoder_(digital)#/editor/4</a>
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Binary_decoder/rvbFldxN">Binary decoder</a></li>
<li><a href="/facts/Multiplexer/lVro0Sfz">Multiplexer</a> (MUX)</li>
<li><a href="/facts/Priority_encoder/s1LDIl1G">Priority encoder</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Binary Encoders And Their Applications". Electronics Hub. 2015-06-29. Retrieved 2017-05-01. <a href="http://www.electronicshub.org/binary-encoder/" target="_blank">http://www.electronicshub.org/binary-encoder/</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
</ol>

Encoder (digital) open-in-new

Encoder (digital)