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How to analyze the signal of satellite TV LNB

Author:小闻 ComeFrom:闻颂智能科技有限公司 Date:2019-11-11 8:38:08 Hits:149

  The downlink converter of satellite TV can also be locally connected to LNB (or the outdoor unit of satellite TV). It consists of a microwave low noise amplifier, a microwave mixer, a first local muffler and a second intermediate frequency amplifier.
General satellite receiving system mainly includes:


  (1)antenna;

  (2)feed;

  (3)lownoisedownconverter,alsoknownashighfrequencyhead(acomponentintegratedbylownoiseamplifieranddownconverter),isrepresentedbyLNB;

  (4)cable;

  (5)terminalconnector;

  (6)satellitereceiver;

  (7)televisionreceiver.

  BecausethesatellitedownlinkmicrowavesignalreceivedbythegroundantennainthesatelliteTVreceivingsystemisveryweakafteralongdistancetransmissionofabout40000km,theoutputcarrierpoweroftheantennafeedisusuallyabout-90dbmw.Ifthefeederlossis0.5dB,theinputcarrierpowerofLNAis-90.5dbmw.Thelossofthefirstfrequencyconverterandband.

 passfilterisabout10dB,andthegainofthefirstintermediateamplifierisabout30dB.Inthisway,iftheLNAgivesagainof(4050)dB,theoutputterminalofthedownconvertercanoutput(-3020)dbmwsignal.Therefore,thefunctionofsatelliteTVdownconverteristoamplifyandconvertthereceivedsatellitedownlinkfrequencysignalwithlownoiseundertheconditionofensuringtheoriginalsignalqualityparameters.

  ThelownoisedownconverterofsatelliteTVisalsocalledthehighfrequencyhead(alsoknownastheoutdoorunitofsatelliteTV).Itiscomposedofmicrowavelownoiseamplifier,microwavemixer,thefirstlocaloscillatorandthefirstintermediatefrequencypreamplifier.

  GeneralsatelliteTVreceivingsystemmainlyincludes:

  (1)antenna;

  (2)feed;

  (3)lownoisedownconverter,alsoknownashighfrequencyhead(acomponentintegratedbylownoiseamplifieranddownconverter),isrepresentedbyLNB;

  (4)cable;

  (5)termnalconnector;

  (6)satellitereceiver;

  (7)televisionreceiver.

  BecausethesatellitedownlinkmicrowavesignalreceivedbythegroundantennainthesatelliteTVreceivingsystemisveryweakafteralongdistancetransmissionofabout40000km,theoutputcarrierpoweroftheantennafeedisusuallyabout90dbmw.Ifthefeederlossis0.5dB,theinputcarrierpowerofLNAis-90.5dbmw.Thelossofthefirstfrequencyconverterandband-

Thefilteroutputs10dBandthefirstintermediateamplifieroutputs30dB.Inthismode,ifthevibrationfrequencyis(4050)dB,theoutputterminaloftheoutputconverteroutputs(-3020)dbmwsignal.Therefore,undertheconditionofensuringtheoriginalsignalqualityparameters,thefunctionofsatelliteTV LNB canamplifyandconvertthereceivedlownoisesatellitedownlinkfrequencysignal.

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