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  25 <div class="toc">
  26 <div class="tocheader toctoggle" id="toc__header">Table of Contents</div>
  27 <div id="toc__inside">
  28
  29 <ul class="toc">
  30 <li class="level1"><div class="li"><span class="li"><a href="#geda_gaf_rf_cascade_symbols_and_netlister" class="toc">gEDA/gaf RF Cascade Symbols and Netlister</a></span></div>
  31 <ul class="toc">
  32 <li class="level2"><div class="li"><span class="li"><a href="#overview" class="toc">Overview</a></span></div></li>
  33 <li class="level2"><div class="li"><span class="li"><a href="#requirements" class="toc">Requirements</a></span></div></li>
  34 <li class="level2"><div class="li"><span class="li"><a href="#creating_schematics" class="toc">Creating Schematics</a></span></div></li>
  35 <li class="level2"><div class="li"><span class="li"><a href="#extracting_the_cascade_input_file" class="toc">Extracting the Cascade Input File</a></span></div></li>
  36 <li class="level2"><div class="li"><span class="li"><a href="#running_cascade" class="toc">Running Cascade</a></span></div></li>
  37 <li class="level2"><div class="li"><span class="li"><a href="#appendix_a_--_symbols_in_the_library" class="toc">Appendix A -- Symbols in the Library</a></span></div>
  38 <ul class="toc">
  39 <li class="level3"><div class="li"><span class="li"><a href="#sources_cascade-source" class="toc">Sources (cascade-source)</a></span></div></li>
  40 <li class="level3"><div class="li"><span class="li"><a href="#defaults_cascade-default" class="toc">Defaults (cascade-default)</a></span></div></li>
  41 <li class="level3"><div class="li"><span class="li"><a href="#elements" class="toc">Elements</a></span></div></li>
  42 </ul>
  43 </li>
  44 <li class="level2"><div class="li"><span class="li"><a href="#example" class="toc">Example</a></span></div>
  45 <ul class="toc">
  46 <li class="level3"><div class="li"><span class="li"><a href="#example_schematics" class="toc">Example Schematics</a></span></div></li>
  47 <li class="level3"><div class="li"><span class="li"><a href="#netlist_the_design" class="toc">Netlist the Design</a></span></div></li>
  48 <li class="level3"><div class="li"><span class="li"><a href="#run_the_analysis" class="toc">Run the Analysis</a></span></div></li>
  49 </ul>
  50 </li>
  51 <li class="level2"><div class="li"><span class="li"><a href="#document_revision_history" class="toc">Document Revision History</a></span></div></li></ul>
  52 </li></ul>
  53 </div>
  54 </div>
  55
  56
  57
  58 <h1><a name="geda_gaf_rf_cascade_symbols_and_netlister" id="geda_gaf_rf_cascade_symbols_and_netlister">gEDA/gaf RF Cascade Symbols and Netlister</a></h1>
  59 <div class="level1">
  60
  61 <p>
  62 by: Dan McMahill
  63 </p>
  64
  65 <p>
  66 This document is released under <a href="http://www.gnu.org/copyleft/fdl.html" class="urlextern" title="http://www.gnu.org/copyleft/fdl.html"  rel="nofollow">GFDL</a>
  67 </p>
  68
  69 <p>
  70 December 3rd, 2003
  71 </p>
  72
  73 </div>
  74 <!-- SECTION "gEDA/gaf RF Cascade Symbols and Netlister" [1-173] -->
  75 <h2><a name="overview" id="overview">Overview</a></h2>
  76 <div class="level2">
  77
  78 <p>
  79 This document describes the symbol library and gnetlist backend which support driving RF Cascade (<a href="http://rfcascade.sourceforge.net/" class="urlextern" title="http://rfcascade.sourceforge.net"  rel="nofollow">http://rfcascade.sourceforge.net</a>) simulations from the gEDA/gaf system. Cascade is a noise figure and distortion analysis tool geared towards radio receiver design.<br/>
  80  The basic steps involved with using gEDA as the frontend for Cascade simulations are:
  81 </p>
  82 <ol>
  83 <li class="level1"><div class="li"> Create schematics of the circuit.</div>
  84 </li>
  85 <li class="level1"><div class="li"> Extract the netlist.</div>
  86 </li>
  87 <li class="level1"><div class="li"> Run Cascade.</div>
  88 </li>
  89 </ol>
  90
  91 </div>
  92 <!-- SECTION "Overview" [174-630] -->
  93 <h2><a name="requirements" id="requirements">Requirements</a></h2>
  94 <div class="level2">
  95
  96 <p>
  97 You will need the following programs to be installed:
  98 </p>
  99 <ul>
 100 <li class="level1"><div class="li"> A recent version of gEDA/gaf. To see if your version is recent enough, see if the directory <strong><code>$prefix/share/gEDA/sym/cascade</code></strong> exists. <strong><code>$prefix</code></strong> is the installation prefix for gEDA on your system.</div>
 101 </li>
 102 <li class="level1"><div class="li"> RF Cascade. The executable is usually called cascade. If you do not have Cascade available on your system, you will need to get a copy from <a href="http://rfcascade.sourceforge.net/" class="urlextern" title="http://rfcascade.sourceforge.net"  rel="nofollow">http://rfcascade.sourceforge.net</a>.</div>
 103 </li>
 104 </ul>
 105
 106 </div>
 107 <!-- SECTION "Requirements" [631-1103] -->
 108 <h2><a name="creating_schematics" id="creating_schematics">Creating Schematics</a></h2>
 109 <div class="level2">
 110
 111 <p>
 112 When creating a block diagram in the gschem schematic editor, use only the symbols from the cascade library. Every block diagram must have a \cascadesource” element. In addition, the block diagram must be a simple cascade. No parallel paths or branches are allowed.<br/>
 113  All instances must have a unique reference designator. For a receiver block diagram, this is often times best achieved by manually entering them. The only restriction on reference designator names is that they contain no spaces. A descriptive name such as \RF Filter” or \First Mixer” is useful as it will show up in the cascade output report.
 114 </p>
 115
 116 </div>
 117 <!-- SECTION "Creating Schematics" [1104-1748] -->
 118 <h2><a name="extracting_the_cascade_input_file" id="extracting_the_cascade_input_file">Extracting the Cascade Input File</a></h2>
 119 <div class="level2">
 120
 121 <p>
 122 To extract the Cascade input file, run:
 123 </p>
 124 <pre class="code">gnetlist -g cascade -o test.cas file1.sch [file2.sch ...]</pre>
 125
 126 <p>
 127 For the example file contained in this archive, you can run:
 128 </p>
 129 <pre class="code">gnetlist -g cascade -o example.cas example.sch</pre>
 130
 131 <p>
 132 The netlist will be left in <strong><code>example.cas</code></strong>.
 133 </p>
 134
 135 </div>
 136 <!-- SECTION "Extracting the Cascade Input File" [1749-2078] -->
 137 <h2><a name="running_cascade" id="running_cascade">Running Cascade</a></h2>
 138 <div class="level2">
 139
 140 <p>
 141 Cascade is exceptionally simple to run. Just run:
 142 </p>
 143 <pre class="code">cascade example.cas &gt; example.out</pre>
 144
 145 <p>
 146 to run the analysis on the system contained in the file <strong><code>example.cas</code></strong> and write the results to the file <strong><code>example.out</code></strong>. Refer to the Cascade documentation for complete details.
 147 </p>
 148
 149 </div>
 150 <!-- SECTION "Running Cascade" [2079-2393] -->
 151 <h2><a name="appendix_a_--_symbols_in_the_library" id="appendix_a_--_symbols_in_the_library">Appendix A -- Symbols in the Library</a></h2>
 152 <div class="level2">
 153
 154 <p>
 155 Please note that all instances must have the <strong><code>refdes=</code></strong> attribute set.
 156 </p>
 157
 158 </div>
 159 <!-- SECTION "Appendix A -- Symbols in the Library" [2394-2519] -->
 160 <h3><a name="sources_cascade-source" id="sources_cascade-source">Sources (cascade-source)</a></h3>
 161 <div class="level3">
 162
 163 <p>
 164 Source. Attributes:
 165 </p>
 166 <ul>
 167 <li class="level1"><div class="li"> C=Carrier level in dBm. Optional.</div>
 168 </li>
 169 <li class="level1"><div class="li"> CN0=Carrier to Noise Spectral Density Ratio in dBm/Hz. Optional.</div>
 170 </li>
 171 <li class="level1"><div class="li"> CN=Carrier to Noise Ratio in dB. Optional.</div>
 172 </li>
 173 <li class="level1"><div class="li"> BW=Signal Bandwidth in Hz. Optional, but requred if CN= is used.</div>
 174 </li>
 175 </ul>
 176
 177 </div>
 178 <!-- SECTION "Sources (cascade-source)" [2520-2798] -->
 179 <h3><a name="defaults_cascade-default" id="defaults_cascade-default">Defaults (cascade-default)</a></h3>
 180 <div class="level3">
 181
 182 <p>
 183 This symbol sets the default impedance levels as well as the correlation coeffcient used for third order distortion calculations. There are two versions of this symbol. One is used to set the defaults at the beginnng of the definition. The other can be placed in series with the cascade to change the defaults part way through. This is useful if you wish to change impedance levels in the middle of the receiver chain. Attributes:
 184 </p>
 185 <ul>
 186 <li class="level1"><div class="li"> RIN=Default block input resistance in Ohms. Optional.</div>
 187 </li>
 188 <li class="level1"><div class="li"> ROUT=Default block output resistance in Ohms. Optional.</div>
 189 </li>
 190 <li class="level1"><div class="li"> RHO=Default third order distortion correlation coeffcient. Optional.</div>
 191 </li>
 192 </ul>
 193
 194 </div>
 195 <!-- SECTION "Defaults (cascade-default)" [2799-3458] -->
 196 <h3><a name="elements" id="elements">Elements</a></h3>
 197 <div class="level3">
 198
 199 <p>
 200 Cascade characterizes each block in a system by its gain and optionally noise figure and third order intercept point. As such, there is no distinction between various elements such as amplifiers, filters, and mixers. The gEDA/gaf RF Cascade symbol library contains different symbols for clarity in the diagram only. The currently available element symbols are: Attributes:
 201 </p>
 202 <table class="inline">
 203         <tr>
 204                 <td>cascade-amp</td><td>Amplifier</td>
 205         </tr>
 206         <tr>
 207                 <td>cascade-filter</td><td>Filter</td>
 208         </tr>
 209         <tr>
 210                 <td>cascade-mixer</td><td>Mixer</td>
 211         </tr>
 212         <tr>
 213                 <td>cascade-transformer</td><td>Transformer</td>
 214         </tr>
 215         <tr>
 216                 <td colspan="2"> </td>
 217         </tr>
 218         <tr>
 219                 <td colspan="2"> Table 1: Element Types </td>
 220         </tr>
 221 </table>
 222 <ul>
 223 <li class="level1"><div class="li"> Gain is specified by one of the following:</div>
 224 <ul>
 225 <li class="level2"><div class="li"> <strong>G</strong>=Power gain in dB.</div>
 226 </li>
 227 <li class="level2"><div class="li"> <strong>GP</strong>=Power gain in dB.</div>
 228 </li>
 229 <li class="level2"><div class="li"> <strong>GV</strong>=Voltage gain in dB.</div>
 230 </li>
 231 </ul>
 232 </li>
 233 <li class="level1"><div class="li"> <strong>NF</strong>=Noise Figure in dB. Optional.</div>
 234 </li>
 235 <li class="level1"><div class="li"> <strong>IIP3</strong>=Input Third Order Intercept Point in dBm. Optional.</div>
 236 </li>
 237 <li class="level1"><div class="li"> <strong>RIN</strong>=Block input resistance in Ohms. Optional.</div>
 238 </li>
 239 <li class="level1"><div class="li"> <strong>ROUT</strong>=Block output resistance in Ohms. Optional.</div>
 240 </li>
 241 <li class="level1"><div class="li"> <strong>RHO</strong>=Third order distortion correlation coeffcient. Optional.</div>
 242 </li>
 243 </ul>
 244
 245 </div>
 246 <!-- SECTION "Elements" [3459-4416] -->
 247 <h2><a name="example" id="example">Example</a></h2>
 248 <div class="level2">
 249
 250 <p>
 251 This appendix provides a simple example of the entire process of generating a schematic, producing a Cascade input file, running an analysis and looking at the result.
 252 </p>
 253
 254 </div>
 255 <!-- SECTION "Example" [4417-4605] -->
 256 <h3><a name="example_schematics" id="example_schematics">Example Schematics</a></h3>
 257 <div class="level3">
 258
 259 <p>
 260 Figure 1 shows the schematic of a simple receiver signal chain.<br/>
 261  Figure 2 shows the contents of the example.cas file.
 262 </p>
 263 <table class="inline">
 264         <tr>
 265                 <td> <a href="_detail/geda_rf_cascade_figure1.html" class="media" title="geda:rf_cascade_figure1.jpg"><img src="_media/geda_rf_cascade_figure1.jpg" class="media" title="rf_cascade_figure1.jpg" alt="rf_cascade_figure1.jpg" /></a> </td>
 266         </tr>
 267         <tr>
 268                 <td> <a href="_detail/geda_rf_cascade_figure2.html" class="media" title="geda:rf_cascade_figure2.jpg"><img src="_media/geda_rf_cascade_figure2.jpg" class="media" title="rf_cascade_figure2.jpg" alt="rf_cascade_figure2.jpg" /></a> </td>
 269         </tr>
 270 </table>
 271
 272 </div>
 273 <!-- SECTION "Example Schematics" [4606-4829] -->
 274 <h3><a name="netlist_the_design" id="netlist_the_design">Netlist the Design</a></h3>
 275 <div class="level3">
 276
 277 <p>
 278 To netlist the design, run:
 279 </p>
 280 <pre class="code">gnetlist -g cascade example.cas example.sch</pre>
 281
 282 </div>
 283 <!-- SECTION "Netlist the Design" [4830-4944] -->
 284 <h3><a name="run_the_analysis" id="run_the_analysis">Run the Analysis</a></h3>
 285 <div class="level3">
 286
 287 <p>
 288 Run the analysis with:
 289 </p>
 290 <pre class="code">cascade example.cas</pre>
 291
 292 </div>
 293 <!-- SECTION "Run the Analysis" [4945-5028] -->
 294 <h2><a name="document_revision_history" id="document_revision_history">Document Revision History</a></h2>
 295 <div class="level2">
 296 <table class="inline">
 297         <tr>
 298                 <td>December 3rd, 2003</td><td>Created cascade.tex</td>
 299         </tr>
 300 </table>
 301
 302 </div>
 303 <!-- SECTION "Document Revision History" [5029-] --></div>
 304 </body>
 305 </html>