标签: noisecurrent

:AnRFamplifierisanactivenetworkthatincreasestheamplitudeofweaksignals,therebyallowingfurtherprocessingbythereceiver.ReceiveramplificationisdistributedbetweenRFandIFstagesthroughoutthesystem,andanidealamplifierincreasesthedesiredsignalamplitudewithoutaddingdistortionornoise.Unfortunately,amplifiersareknowntoaddnoiseanddistortiontothedesiredsignal.Inareceiverchain,thefirstamplifieraftertheantennacontributesmosttothesystemnoisefigure.Addinggaininfrontofanoisynetworkreducesthenoisecontributionfromthatnetwork.……