<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0035-001X</journal-id>
<journal-title><![CDATA[Revista mexicana de física]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fis.]]></abbrev-journal-title>
<issn>0035-001X</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0035-001X2012000600011</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Modelo de radio propagación a través de un canal con ruido gaussiano]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Fermín]]></surname>
<given-names><![CDATA[José R.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Pizarro]]></surname>
<given-names><![CDATA[Juan C.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad del Zulia Facultad Experimental de Ciencias Departamento de Física]]></institution>
<addr-line><![CDATA[Zulia ]]></addr-line>
<country>Venezuela</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2012</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2012</year>
</pub-date>
<volume>58</volume>
<numero>6</numero>
<fpage>515</fpage>
<lpage>520</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2012000600011&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2012000600011&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2012000600011&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Presentamos un modelo físico para la propagación de ondas de radio a través de un canal con ruido blanco Gaussiano. El canal es continuo y simulado a través de un modelo lineal disipativo, que consiste de una cuerda flexible de densidad uniforme y sumergida en un bario térmico. El canal es caracterizado mediante la razón señal-ruido, la cual es calculada en función de la temperatura, frecuencia de la señal y la distancia de propagación. Para cierto valor de temperatura, distancia de propagación y frecuencia la SNR excede el umbral de Shannon por debajo del cual la transmisión libre de errores no es posible.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[We present a physical model of radio waves propagation through a channel with white Gaussian noise. The continuous channel is simulated using a dissipative linear model, which consists of a flexible string of uniform density and immersed into a thermal bath. The channel is characterized by signal to noise ratio, which is calculated as a function of temperature, frequency of the signal and the propagation distance. For some value of temperature, propagation distance and frequency, the SNR exceeds the threshold below which Shannon's error-free transmission is not possible.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Sistema lineal]]></kwd>
<kwd lng="es"><![CDATA[ruido térmico]]></kwd>
<kwd lng="es"><![CDATA[relación señal-ruido (SNR)]]></kwd>
<kwd lng="es"><![CDATA[canal Gaussiano]]></kwd>
<kwd lng="es"><![CDATA[canal continuo]]></kwd>
<kwd lng="en"><![CDATA[Linear system]]></kwd>
<kwd lng="en"><![CDATA[thermal noise]]></kwd>
<kwd lng="en"><![CDATA[signal to noise ratio (SNR)]]></kwd>
<kwd lng="en"><![CDATA[Gaussian channel]]></kwd>
<kwd lng="en"><![CDATA[continuous channel]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  	    <p align="justify"><font face="verdana" size="4">Instrumentaci&oacute;n</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="center"><font face="verdana" size="4"><b>Modelo de radio propagaci&oacute;n a trav&eacute;s de un canal con ruido gaussiano</b></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="center"><font face="verdana" size="2"><b>Jos&eacute; R. Ferm&iacute;n y Juan C. Pizarro</b></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><i>Departamento de F&iacute;sica, Facultad Experimental de Ciencias, Universidad del Zulia, LUZ, Apartado 256, Maracaibo 4001, Zulia, Venezuela, e&#45;mail:</i> <a href="mailto:jfermin@luz.edu.ve">jfermin@luz.edu.ve</a>; <a href="mailto:jpizarro63@gmail.com">jpizarro63@gmail.com</a></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2">Recibido el 2 de febrero de 2012    ]]></body>
<body><![CDATA[<br> 	Aceptado el 7 de septiembre de 2012</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>  	    <p align="justify"><font face="verdana" size="2">Presentamos un modelo f&iacute;sico para la propagaci&oacute;n de ondas de radio a trav&eacute;s de un canal con ruido blanco Gaussiano. El canal es continuo y simulado a trav&eacute;s de un modelo lineal disipativo, que consiste de una cuerda flexible de densidad uniforme y sumergida en un bario t&eacute;rmico. El canal es caracterizado mediante la raz&oacute;n se&ntilde;al&#45;ruido, la cual es calculada en funci&oacute;n de la temperatura, frecuencia de la se&ntilde;al y la distancia de propagaci&oacute;n. Para cierto valor de temperatura, distancia de propagaci&oacute;n y frecuencia la SNR excede el umbral de Shannon por debajo del cual la transmisi&oacute;n libre de errores no es posible.</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Descriptores:</b> Sistema lineal; ruido t&eacute;rmico; relaci&oacute;n se&ntilde;al&#45;ruido (SNR); canal Gaussiano; canal continuo.</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>  	    <p align="justify"><font face="verdana" size="2">We present a physical model of radio waves propagation through a channel with white Gaussian noise. The continuous channel is simulated using a dissipative linear model, which consists of a flexible string of uniform density and immersed into a thermal bath. The channel is characterized by signal to noise ratio, which is calculated as a function of temperature, frequency of the signal and the propagation distance. For some value of temperature, propagation distance and frequency, the SNR exceeds the threshold below which Shannon's error&#45;free transmission is not possible.</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Keywords:</b> Linear system; thermal noise; signal to noise ratio (SNR); Gaussian channel; continuous channel.</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">PACS: 05.40.Ca; 02.50.Ey; 05.45.Xt</font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v58n6/v58n6a11.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>  	    <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Referencias</b></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">1. 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