144 Keysight N9010A EXA Service GuideRF Section Troubleshooting (RF/Microwave Analyzers)RF Section DescriptionRF Section Theory of OperationA9 Input Attenuator AThis assembly has two 2 dB attenuator sections, a DC block and a cal signalinput port. With the DC block switched in (AC coupled mode), the low endminimum frequency range increases from 9 kHz to 10 MHz due to capacitiveeffects.A10 Input Attenuator BThis assembly has a total of 66 dB of attenuation to control the RF level goingto the mixer assemblies in the A13 RF Front End Assembly. There is a 6 dB,10 dB, 20 dB, and 30 dB section in the A10 assembly. Total input attenuationwith the A9 and the A10 combined is 60 dB in 10 dB steps (2 dB steps if OptionFSA, Fine Step Attenuator, is installed).A11 Low Band SwitchThis assembly operates across the entire frequency range of the analyzer. Theswitch has 2 main functions:— Switch RF input frequencies from 9 kHz to 3.59 GHz RF Output to A13 RFFront End Assembly.— Switch RF input frequencies from 3.6 GHz to 26.5 GHz Microwave RFOutput to A12, YTF Preselector.— Optional high band preamplifier, which has a typical gain of 30 dB and anoise figure from 9 dB up to 7 GHz.A12 YTF PreselectorThe YTF Preselector is used for input frequencies greater than 3.6 GHz. Signalsless than 3.6 GHz bypass the YTF assembly and are routed directly to the A13RF Front End Assembly. The YTF Preselector is a YIG tunable bandpass filterwhose main purpose is to filter out unwanted spurious or image responsesignals. When the YTF is calibrated, the tunable bandpass will track the RFinput signal. The YTF Preselector has a 3 dB bandwidth greater than 40 MHzand an insertion loss of ~ 6.5 dB.The preselector requires centering for optimum amplitude accuracy. The AutoAlign routine will perform a rough centering during the preselector two-pointtuning algorithm. However, when troubleshooting, press Amplitude,Preselector Center to manually center the preselector.The YTF Preselector is not present in analyzers with Option 503, 3.6 GHzfrequency range.
