200 N9030B PXA Signal Analyzer Service GuideFront End Control TroubleshootingA15 Front End Control DescriptionA15 Front End Control DescriptionPurposeThe A15 Front End Controller board functionality can be broken down into (3)main categories1. Provides switch control logic and bias voltages to the major RF front endassemblies in the N9030B Signal Analyzer.2. Contains on board circuitry providing various signal outputs to otherlocations within the analyzer.3. Provides control logic for various instrument options within the analyzer.These signals are routed to and from the A15 via ribbon cables, wiringharnesses and coaxial cables. The RF front end assemblies require the correctcontrol logic and bias in order to function properly. If the voltages from the A15are not correct, the RF input signals will most likely be displayed at an incorrectpower level if they even get displayed at all.Standard RF Assemblies Controlled by the A15:— A9 Input Attenuator A (4 dB total for Opt 503, 508, 513, 526; 10 dB total forOpt 544, 550)— A10 Input Attenuator B (66 dB total for Opt 503, 508, 513, 526; 60 dB totalfor Opt 544, 550)— A11 Low Band Switch— A12 YIG Tuned Filter— A13 RF Front End AssemblyA15 On Board Circuits:— RF Burst Trigger (When set to Relative Trigger or when start frequency is> 300 MHz.)— Switched IF Filter Control— 1st L.O. Optimization— YTF Tune Ramp— Preselector Tune Out (Provides output voltage, not specified, reserved forfuture use)— Mixer Bias— Amplifier Bias— Switch Control— Sweep Ramp (reserved for future use)
