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  <xs:element id="hlit_AmortizationofIntangibleOperatingExpenses" abstract="false" name="AmortizationofIntangibleOperatingExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hlit_AdjustmentToAPICReclassificationFromMezzanineEquityToEquity" abstract="false" name="AdjustmentToAPICReclassificationFromMezzanineEquityToEquity" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="hlit_AccountingStandardsUpdate202006MemberMember" abstract="true" name="AccountingStandardsUpdate202006MemberMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="hlit_InternationalMember" abstract="true" name="InternationalMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="hlit_SaaSServiceMember" abstract="true" name="SaaSServiceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="hlit_Stockpricegreaterorequal130percentofNoteConversionPriceMember" abstract="true" name="Stockpricegreaterorequal130percentofNoteConversionPriceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="hlit_ComcastCableOSSoftwareLicenseAgreementMember" abstract="true" name="ComcastCableOSSoftwareLicenseAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="hlit_ConvertibleNotedue2022Member" abstract="true" name="ConvertibleNotedue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
</xs:schema>
