Digital signal conditioning

<h2 id="introduction-and-digital-fundamentals">Introduction and digital fundamentals</h2>
<p>Digital <a href="/facts/Signal_conditioning/CPfjRUAJ">signal conditioning</a> in process control means finding a way to represent <a href="/facts/Analog_signal/xDbb4uB5">analog</a> process information in digital format.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
Use of in control system is particularly valuable number of other reasons, however:
</p>
<ol><li>A computer can control <a href="/facts/Multivibrator/kV2bRxeo">multivibrator</a> process-control system.</li>
<li>Nonlinearities in sensor output can be linearized by the computer.</li>
<li>Complicated control equation can be solved quickly and modified as needed.</li>
<li><a href="/facts/Computer_network/3w5RM99p">Networking</a> of control computers allow a large process-control complex to operate in a fully integrated fashion.</li></ol>
<h2 id="digital-information">Digital information</h2>
<p>The use of digital techniques in process control system hat process variable measurements and control information be encoded into a digital form. Digital signals themselves are simply two-scale (binary)<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> These levels may be represented  in many ways. For example, two volts, two currents, two frequencies etc.
</p>
<h2 id="digital-words">Digital words</h2>
<p>Given the simple binary information that is carried by signal digital, it is clear that multiple signals must be used to describe analog information. Generally, this is done by using an assemblage of digital levels to construct a binary number, often called a <i>word</i>. The individual digital levels are referred to as <i>bits</i> of the word. Thus, for example, a 6-bit word consists of six independent digital levels, such as 
  
    
      
        
          101011
          
            2
          
        
      
    
    {\displaystyle 101011_{2}}
  
, which can be thought of as a six-digit base 2 number. An important consideration, then, is how the analog information is encoded into this digital word.
</p>
<h2 id="digital-whole-numbers">Digital whole numbers</h2>
<p>One of the most common schemes for encoding analog into s digital words is to use the straight counting of decimal (or base 10) and binary numbers representations.
</p>
<h2 id="some-examples">Some examples</h2>
<p>
  
    
      
        E
        x
        .1
        .
      
    
    {\displaystyle Ex.1.}
  
 Find the base 10 equivalent of the binary whole number 
  
    
      
        
          00100111
          
            2
          
        
      
    
    {\displaystyle 00100111_{2}}
  
 ?
Solution.
As in the base 10 system, zero preceding the first significant digit do not contribute. Thus, the binary number is actually

100111
      
    
    {\displaystyle 100111}
  
, and 
  
    
      
        n
        =
        5
      
    
    {\displaystyle n=5}
  
, decimal equivalent can be computed as follows:

N
          
            1
          
        
        0
        =
        
          a
          
            5
          
        
        
          2
          
            5
          
        
        +
        
          a
          
            4
          
        
        
          2
          
            4
          
        
        +
        .
        .
        .
        .
        +
        
          a
          
            1
          
        
        
          2
          
            1
          
        
        +
        
          a
          
            0
          
        
        
          2
          
            0
          
        
      
    
    {\displaystyle N_{1}0=a_{5}2^{5}+a_{4}2^{4}+....+a_{1}2^{1}+a_{0}2^{0}}

N
          
            1
          
        
        0
        =
        (
        1
        )
        
          2
          
            5
          
        
        +
        (
        0
        )
        
          2
          
            4
          
        
        +
        (
        0
        )
        
          2
          
            3
          
        
        +
        (
        1
        )
        
          2
          
            2
          
        
        +
        (
        1
        )
        
          2
          
            1
          
        
        +
        (
        1
        )
        
          2
          
            0
          
        
      
    
    {\displaystyle N_{1}0=(1)2^{5}+(0)2^{4}+(0)2^{3}+(1)2^{2}+(1)2^{1}+(1)2^{0}}

N
          
            1
          
        
        0
        =
        32
        +
        4
        +
        2
        +
        1
      
    
    {\displaystyle N_{1}0=32+4+2+1}

N
          
            1
          
        
        0
        =
        39
      
    
    {\displaystyle N_{1}0=39}

</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Signal_conditioning/CPfjRUAJ">Signal conditioning</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="http://iopscience.iop.org/0022-3735/15/8/001">http://iopscience.iop.org/0022-3735/15/8/001</a></li>
<li><a href="http://www.hbm.com/en/menu/products/industrial-amplifiers/">http://www.hbm.com/en/menu/products/industrial-amplifiers/</a></li>
<li><a href="http://sine.ni.com/np/app/main/p/ap/daq/lang/en/pg/1/sn/n17:daq,n21:11/fmid/2998/">http://sine.ni.com/np/app/main/p/ap/daq/lang/en/pg/1/sn/n17:daq,n21:11/fmid/2998/</a></li></ul>

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

<ol>
<li id="fn:1"><p>Curtis D. Johnson, "Process Control Instrumentation Technology" Sep 6, 2006. ISBN 0-13-441305-9 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Ramón Pallás-Areny, John G. Webster, "Sensors and Signal Conditioning, 2nd Edition", November 2000. ISBN 978-0-471-33232-9 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Goodwin, Graham C., Richard H. Middleton, and H. Vincent Poor. "High-speed digital signal processing and control." Proceedings of the IEEE 80.2 (1992). <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
</ol>

Digital signal conditioning open-in-new

Digital signal conditioning