N5161A/62A/81A/82A/83A MXG Signal Generators User's Guide

TroubleshootingRF OutputRF Output Power too Low• If the AMPLITUDE area of the display shows the OFFS indicator, eliminate the offset:Press Amptd > More 1 of 2 > Amptd Offset > 0 > dB. See also “Setting an Output Offset” on page 115.• If the AMPLITUDE area of the display shows the REF indicator, turn off the reference mode:1. Press Amptd > More > Amptd Ref Off On until Off highlights.2. Reset the output power to the desired level.See also “Setting an Output Reference” on page 116.• If you are using the signal generator with an external mixer, see page 318.• If you are using the signal generator with a spectrum analyzer, see page 317.• If pulse modulation is on, turn off the ALC, and check that pulse width is within specifications.DistortionIf you edit and resave a segment in a waveform sequence, the sequence does not automaticallyupdate the RMS value stored in it’s header. This can cause distortion on the output signal. Displaythe sequence header information and recalculate the RMS value (see page 149).Signal Loss While Working with a Spectrum AnalyzerCAUTIONTo avoid damaging or degrading the performance of the MXG, do not exceed 33 dBm(2W) maximum of reverse power levels at the RF input. See also Tips for PreventingSignal Generator Damage on www.agilent.com.The effects of reverse power can cause problems with the RF output when you use the signalgenerator with a spectrum analyzer that does not have preselection. Use an unleveled operating mode(described on page 112).A spectrum analyzer can have as much as +5 dBm LO feedthrough at its RF input port at somefrequencies. If the frequency difference between the LO feedthrough and the RF carrier is less thanthe ALC bandwidth, the LO’s reverse power can amplitude modulate the signal generator’s RF output.The rate of the undesired AM equals the difference in frequency between the spectrum analyzer’s LOfeedthrough and the signal generator’s RF carrier.Reverse power problems can be solved by using one of the unleveled operating modes.See:• “ALC Off Mode” on page 112and• “Power Search Mode” on page 113Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide 317