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67  <div class="navpath"><b>itpp</b>::<a class="el" href="classitpp_1_1AWGN__Channel.html">AWGN_Channel</a>
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71<h1>itpp::AWGN_Channel Class Reference<br>
72<small>
73[<a class="el" href="group__channels.html">Channel Modeling</a>]</small>
74</h1><!-- doxytag: class="itpp::AWGN_Channel" -->Ordinary AWGN Channel for cvec or vec inputs and outputs. 
75<a href="#_details">More...</a>
76<p>
77<code>#include &lt;<a class="el" href="channel_8h-source.html">channel.h</a>&gt;</code>
78<p>
79
80<p>
81<a href="classitpp_1_1AWGN__Channel-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0">
82<tr><td></td></tr>
83<tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr>
84<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="7894594d815d194c44b191162289e764"></a><!-- doxytag: member="itpp::AWGN_Channel::AWGN_Channel" ref="7894594d815d194c44b191162289e764" args="(double noisevar=0.0)" -->
85&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1AWGN__Channel.html#7894594d815d194c44b191162289e764">AWGN_Channel</a> (double noisevar=0.0)</td></tr>
86
87<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Class constructor. Sets the noise variance (for complex-valued channels the sum of real and imaginary parts). <br></td></tr>
88<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="edf43a1a192a6c474ef915c297e9fcbb"></a><!-- doxytag: member="itpp::AWGN_Channel::set_noise" ref="edf43a1a192a6c474ef915c297e9fcbb" args="(double noisevar)" -->
89void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1AWGN__Channel.html#edf43a1a192a6c474ef915c297e9fcbb">set_noise</a> (double noisevar)</td></tr>
90
91<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Set noise variance (for complex-valued channels the sum of real and imaginary parts). <br></td></tr>
92<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="13fb914542cdad6909fe9e866322a031"></a><!-- doxytag: member="itpp::AWGN_Channel::get_noise" ref="13fb914542cdad6909fe9e866322a031" args="() const " -->
93double&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1AWGN__Channel.html#13fb914542cdad6909fe9e866322a031">get_noise</a> () const </td></tr>
94
95<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get noise variance (for complex-valued channels the sum of real and imaginary parts). <br></td></tr>
96<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="619607f240984d3c5564c057b60851dc"></a><!-- doxytag: member="itpp::AWGN_Channel::operator()" ref="619607f240984d3c5564c057b60851dc" args="(const cvec &amp;input)" -->
97cvec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1AWGN__Channel.html#619607f240984d3c5564c057b60851dc">operator()</a> (const cvec &amp;input)</td></tr>
98
99<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Feed the complex input <em>input</em> through the complex-valued AWGN channel. <br></td></tr>
100<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="afbd26438bc064a1bfca9c0b36830e64"></a><!-- doxytag: member="itpp::AWGN_Channel::operator()" ref="afbd26438bc064a1bfca9c0b36830e64" args="(const vec &amp;input)" -->
101vec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1AWGN__Channel.html#afbd26438bc064a1bfca9c0b36830e64">operator()</a> (const vec &amp;input)</td></tr>
102
103<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Feed the input <em>through</em> the real-valued AWGN channel. <br></td></tr>
104</table>
105<hr><a name="_details"></a><h2>Detailed Description</h2>
106Ordinary AWGN Channel for cvec or vec inputs and outputs.
107<p>
108For real signals, the input parameter (<em>noisevar</em>) denotes the noise variance per real dimension. Therefore, it should be set to <img class="formulaInl" alt="$N_0/2$" src="form_232.png">, where <img class="formulaInl" alt="$N_0$" src="form_233.png"> is the noise power spectral density. However, in case of complex signals, the input parameter (<em>noisevar</em>) represents the noise variance per complex dimension, i.e. the sum of the variances in the real and imaginary parts, and thus is equal to <img class="formulaInl" alt="$N_0$" src="form_233.png">.<p>
109Example: <div class="fragment"><pre class="fragment"><span class="preprocessor">  #include &lt;<a class="code" href="itcomm_8h.html" title="Include file for the IT++ communications module.">itpp/itcomm.h</a>&gt;</span>
110  <span class="keyword">using namespace </span>itpp;
111
112  <span class="keywordtype">int</span> main() {
113 Initiate the <a class="code" href="classitpp_1_1AWGN__Channel.html#7894594d815d194c44b191162289e764" title="Class constructor. Sets the noise variance (for complex-valued channels the sum of...">AWGN_Channel</a> <span class="keyword">class</span>
114    <span class="keywordtype">double</span> noisevar = 0.1;
115    <a class="code" href="classitpp_1_1AWGN__Channel.html#7894594d815d194c44b191162289e764" title="Class constructor. Sets the noise variance (for complex-valued channels the sum of...">AWGN_Channel</a> awgn_channel(noisevar);
116
117 Initiate a QPSK-modulator, and generate the transmitted signal
118    QPSK qpsk;
119    bvec transmitted_bits = <a class="code" href="group__randgen.html#g5aa06887cf1fd3301b040987924068f0" title="Generates a random bit (equally likely 0s and 1s).">randb</a>(20);
120    cvec transmitted_signal = qpsk.modulate_bits(transmitted_bits);
121
122 Usage of the member operator ()
123    cvec received_signal = awgn_channel(transmitted_signal);
124
125 Demodulate the bits
126    bvec received_bits = qpsk.demodulate_bits(received_signal);
127  }
128</pre></div> <hr>The documentation for this class was generated from the following files:<ul>
129<li><a class="el" href="channel_8h-source.html">channel.h</a><li><a class="el" href="channel_8cpp.html">channel.cpp</a></ul>
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