136 Keysight CXG, EXG, and MXG X-Series Signal Generators Service Guide
Troubleshooting
Unleveled Issues
5. Run the following adjustments:
ALC Linearity Calibration
Absolute Power Calibration
ALC Calibration
6. If the adjustments fail or the unlevel condition persists, replace the A3 RF
assembly.
I/Q Modulator Unlevel
If the I/Q modulator is turned on without a modulating signal, either from the
internal A2 Vector BBG assembly or from the front panel I or Q Inputs, the
instrument will display an unlevel condition when the RF power is turned On.
Use the following procedure to determine what is causing the unlevel condition
when the I/Q modulator is turned on:
1. Return the instrument to a known state by pressing Preset.
2. Verify that the instrument is using the factory I/Q modulator calibration
data by pressing I/Q, I/Q Calibration, Revert to Default Cal Settings.
3. Turn both the output power and modulation On by pressing RF On/Off and
Mod On/Off so that the LEDs below them come on.
4. Using a function generator input a 300 mV sinewave signal at 1 MHz into
the front panel I Input (rear panel if option 1EM).
5. Turn the I/Q modulator on by pressing I/Q, I/Q On.
6. Tune the instrument output to a frequency and power level that causes the
unlevel error to occur.
7. Verify that the Unlevel indicator is now on.
8. Referring to Figure 6-1, remove W7 (W14 and W15 if option 012 is
installed) and W8.
The I and Q Inputs have an input impedance of 50 ohms and a damage
level of 1 VRMS.
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