特点：·准确的回程损耗/SWR测量·可精确的测试传输线和天线·免受现场RF干扰·距离错误窗口显示功能（S120A，S251A/B）·损耗/收益存放（S114B，S332B）·可选瓦特计·可选内置T型连接器（S251A/B）·合成器精确到75ppm技术指标ModelS331AFrequencyrange25to3300MHz(S331A)25to4000MHz(S400A)Freqeuncyaccuracy(CWmode)75ppmFrequencyresolution100kHzImmunitytointerferingRFsignalsupto^*2-15dBmReturnlossSWR Resolution:0.1dB(S120A,S251A)S810A,S818A,S820A)Returnloss:0to54dBSWR:1to65Horizontalrange:0to128*(resolution)Horizontalresolution,rectangularwidowingresolution(meter):Coax:(105*10^8)(up)/△frequency^*3Waveguide:(1.5*10^8)(√(1-(FF1)^2/√frequency)^*4monitor,Option5)Detectorrange:-50to+20dBm,10nWto100mWResolution:0.1dB,0.1*WTracememory40(S331AandS400A)50(S120AandS251A)70(S800Aseries)50(S120AandS251A)70(S800Aseries)^*54(S120AandS251A)6(S800Aseries)RFpowerdetector:+20dBm,50ΩTemperatureStorage:-20℃to75℃Weight1.36kg(3.0lbs.)nom(S120A,S251AandS800Aseries)SizeGeneralRS232:9-pinD-sub,threewireserial