<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">frequency</topic></authority><related type="other"><topic>wavelength</topic></related><related type="other"><topic>hertz</topic></related><related type="broader"><topic>attributes and properties by specific type</topic></related> <note xml:lang="en"><![CDATA[ The rate or recurrence of a repeating vibration, cycle, or wave passing a fixed point in unit time. In physics, frequency is expressed in hertz units, as one cycle per second, or Hz. ]]></note></mads>