<?xml version="1.0" encoding="ISO-8859-1"?><?xml-stylesheet href="/usr/local/vamdoc-1.0.2-kluwer/config/model.xsl" type="text/xsl"?><!DOCTYPE model SYSTEM "/usr/local/vamdoc-1.0.2-kluwer/config/model.dtd"><model>  <symbol>../symbol/freq.png</symbol>  <comments>    <title>Frequency measurement unit</title>    <model_name>FREQ(MIXED_SIGNAL)</model_name>    <library>N/A</library>    <structure>N/A</structure>    <description>The test-bench shows how the current frequency of the input<br></br>signal can be measured by a mixed-signal model. The distance<br></br>in time between two successive crossings of a given threshold<br></br>is measured.<br></br></description>    <link_source><A HREF="../src/freq.vhd">See source code</A></link_source>    <dependency>      <library>IEEE_proposed</library>      <design_unit>ELECTRICAL_SYSTEMS</design_unit>    </dependency>    <dependency>      <library>IEEE</library>      <design_unit>MATH_REAL</design_unit>    </dependency>  </comments>  <interface>    <parameter>      <name>THRESHOLD</name>      <type>real</type>      <default>0.0</default>      <unit>V</unit>      <comment> threshold value for period measurement </comment>    </parameter>    <port>      <port_id>terminal</port_id>      <name>P_1</name>      <port_type>ELECTRICAL</port_type>      <comment> terminal at pin 1</comment>    </port>    <port>      <port_id>terminal</port_id>      <name>P_2</name>      <port_type>ELECTRICAL</port_type>      <comment> terminal at pin 2</comment>    </port>    <port>      <port_id>quantity</port_id>      <name>F_HZ</name>      <port_type>REAL</port_type>      <mode>out</mode>      <comment> output frequency</comment>    </port>  </interface></model>