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67  <div class="navpath"><b>itpp</b>::<a class="el" href="classitpp_1_1Spread__1d.html">Spread_1d</a>
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70<div class="contents">
71<h1>itpp::Spread_1d Class Reference<br>
72<small>
73[<a class="el" href="group__modulators.html">Digital Modulation</a>]</small>
74</h1><!-- doxytag: class="itpp::Spread_1d" -->Spreading of float symbols to float output. 
75<a href="#_details">More...</a>
76<p>
77<code>#include &lt;<a class="el" href="spread_8h-source.html">spread.h</a>&gt;</code>
78<p>
79
80<p>
81<a href="classitpp_1_1Spread__1d-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="c5ff2ad702fcd9c1b448ceaa1e340d3c"></a><!-- doxytag: member="itpp::Spread_1d::Spread_1d" ref="c5ff2ad702fcd9c1b448ceaa1e340d3c" args="()" -->
85&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#c5ff2ad702fcd9c1b448ceaa1e340d3c">Spread_1d</a> ()</td></tr>
86
87<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Constructor. <br></td></tr>
88<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="60dbcd2746277b4f710a917ff34e1b7c"></a><!-- doxytag: member="itpp::Spread_1d::Spread_1d" ref="60dbcd2746277b4f710a917ff34e1b7c" args="(const vec &amp;incode)" -->
89&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#60dbcd2746277b4f710a917ff34e1b7c">Spread_1d</a> (const vec &amp;incode)</td></tr>
90
91<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Constructor. <br></td></tr>
92<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="f183e0c727a5e254ae756732063fa7dd"></a><!-- doxytag: member="itpp::Spread_1d::spread" ref="f183e0c727a5e254ae756732063fa7dd" args="(const vec &amp;symbols, vec &amp;out)" -->
93void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#f183e0c727a5e254ae756732063fa7dd">spread</a> (const vec &amp;symbols, vec &amp;out)</td></tr>
94
95<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Spreading of signal return i out. <br></td></tr>
96<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="fc908fb3d2abeba03fa7108a5675e320"></a><!-- doxytag: member="itpp::Spread_1d::spread" ref="fc908fb3d2abeba03fa7108a5675e320" args="(const vec &amp;symbols)" -->
97vec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#fc908fb3d2abeba03fa7108a5675e320">spread</a> (const vec &amp;symbols)</td></tr>
98
99<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Spreading of signal. <br></td></tr>
100<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="37adb98ca481080a3c7e56d68f644511"></a><!-- doxytag: member="itpp::Spread_1d::despread" ref="37adb98ca481080a3c7e56d68f644511" args="(const vec &amp;rec_signal, vec &amp;out, int timing)" -->
101void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#37adb98ca481080a3c7e56d68f644511">despread</a> (const vec &amp;rec_signal, vec &amp;out, int timing)</td></tr>
102
103<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Despreading of signal. <em>timing</em> is the start position of the first symbol, given in number of samples. <br></td></tr>
104<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="0f3be17eb3791105337c3a751f25f496"></a><!-- doxytag: member="itpp::Spread_1d::despread" ref="0f3be17eb3791105337c3a751f25f496" args="(const vec &amp;rec_signal, int timing)" -->
105vec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#0f3be17eb3791105337c3a751f25f496">despread</a> (const vec &amp;rec_signal, int timing)</td></tr>
106
107<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Despreading of signal. <em>timing</em> is the start position of the first symbol, given in number of samples. <br></td></tr>
108<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="48cfba452d6cb351e4c6253ef564be09"></a><!-- doxytag: member="itpp::Spread_1d::set_code" ref="48cfba452d6cb351e4c6253ef564be09" args="(const vec &amp;incode)" -->
109void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#48cfba452d6cb351e4c6253ef564be09">set_code</a> (const vec &amp;incode)</td></tr>
110
111<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Set the spreading code used for spreading. <br></td></tr>
112<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="b222a17d4a09673384e84127bd07d1fe"></a><!-- doxytag: member="itpp::Spread_1d::get_code" ref="b222a17d4a09673384e84127bd07d1fe" args="()" -->
113vec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#b222a17d4a09673384e84127bd07d1fe">get_code</a> ()</td></tr>
114
115<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Returns the spreading code used. <br></td></tr>
116<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="e4dd18b9b8152e323b8fe955b5df94cf"></a><!-- doxytag: member="itpp::Spread_1d::get_period" ref="e4dd18b9b8152e323b8fe955b5df94cf" args="()" -->
117int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#e4dd18b9b8152e323b8fe955b5df94cf">get_period</a> ()</td></tr>
118
119<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get the period of the code (length of code vector). <br></td></tr>
120<tr><td colspan="2"><br><h2>Protected Attributes</h2></td></tr>
121<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="3c80146fc6bf4669f91f50ac73a466b1"></a><!-- doxytag: member="itpp::Spread_1d::code" ref="3c80146fc6bf4669f91f50ac73a466b1" args="" -->
122vec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#3c80146fc6bf4669f91f50ac73a466b1">code</a></td></tr>
123
124<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">The spreading code. <br></td></tr>
125<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="14f6374aeb08189334c46cdec582f0d7"></a><!-- doxytag: member="itpp::Spread_1d::N" ref="14f6374aeb08189334c46cdec582f0d7" args="" -->
126int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1Spread__1d.html#14f6374aeb08189334c46cdec582f0d7">N</a></td></tr>
127
128<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">The spreading factor. <br></td></tr>
129</table>
130<hr><a name="_details"></a><h2>Detailed Description</h2>
131Spreading of float symbols to float output.
132<p>
133Spreading block for generation of 1-dimensional DS-CDMA signals Useful in the simulation of DS-CDMA systems on chip level or upsampled chip level.<p>
134Obeserve that the spreading is normalized so that the energy per bit is preserved before and after spreading (that is each symbol is multiplied with <code>1/sqrt</code>(N)). Hence, for the multicode case the energy is normalized for one symbol (code) but the transmitted signal consist of a sum of several signals.<p>
135Four different classes exist:<p>
136<ul>
137<li>
138<a class="el" href="classitpp_1_1Spread__1d.html" title="Spreading of float symbols to float output.">Spread_1d</a> for 1-dimensional symbols (e.g. <a class="el" href="classitpp_1_1BPSK.html" title="BPSK modulator with real symbols.">BPSK</a>). </li>
139<li>
140<a class="el" href="classitpp_1_1Spread__2d.html" title="Spreading of complex symbols to complex output.">Spread_2d</a> for 2-dimensional symbols (e.g. <a class="el" href="classitpp_1_1QPSK.html" title="QPSK modulator.">QPSK</a>). </li>
141</ul>
142<p>
143For multicode transmission, that is each user uses several codes in parallel to transmit data, there exist<p>
144<ul>
145<li>
146<a class="el" href="classitpp_1_1Multicode__Spread__1d.html" title="Multicode spreading of float symbols.">Multicode_Spread_1d</a> for 1-dimensional symbols.  </li>
147<li>
148<a class="el" href="classitpp_1_1Multicode__Spread__2d.html" title="Multicode spreading of complex symbols to complex output.">Multicode_Spread_2d</a> for 2-dimensional symbols.  </li>
149</ul>
150<p>
151Example: <div class="fragment"><pre class="fragment"><span class="preprocessor">  #include "<a class="code" href="itcomm_8h.html" title="Include file for the IT++ communications module.">itpp/itcomm.h</a>"</span>
152
153  <span class="keywordtype">int</span> main() {
154
155  <span class="comment">//Generate the spreading code you want to use.</span>
156  vec spreading_code = <span class="stringliteral">"-1 1 -1 1"</span>;
157
158  <span class="comment">//Initiate th Spreading class</span>
159  <a class="code" href="classitpp_1_1Spread__1d.html#c5ff2ad702fcd9c1b448ceaa1e340d3c" title="Constructor.">Spread_1d</a> spread_1d(spreading_code);
160
161  <span class="comment">//Generate the symbols to transmitt</span>
162  bvec transmitted_bits = <a class="code" href="group__randgen.html#g5aa06887cf1fd3301b040987924068f0" title="Generates a random bit (equally likely 0s and 1s).">randb</a>(10);
163  BPSK bpsk;
164  vec transmitted_symbols = bpsk.modulate_bits(transmitted_bits);
165
166  <span class="comment">//Spread the symbols</span>
167  vec transmitted_signal = spread_1d.spread(transmitted_symbols);
168
169  <span class="comment">//Generate the received signal</span>
170  vec received_signal = transmitted_signal;
171
172  <span class="comment">//Despread the received signal</span>
173  vec received_symbols  = spread_1d.despread(received_signal,0);
174
175  <span class="comment">//demodulate the bits</span>
176  bvec received_bits = bpsk.demodulate_bits(received_symbols);
177
178  }
179</pre></div> <hr>The documentation for this class was generated from the following files:<ul>
180<li><a class="el" href="spread_8h-source.html">spread.h</a><li><a class="el" href="spread_8cpp.html">spread.cpp</a></ul>
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