Tektronix RSA3408B, Service Manual

Page: 108 / 250

Adjustment Procedures
4- 18
RSA3408B Analyzer Service Manual
When you display a spectrum and no input signal is present, a spurious emission
at the center frequency may appear regardless of frequency settings. The center
offset calibration cancels those spurious emissions. If the spurious emission is
too obvious when you narrow the span, run the calibration.
NOTE
. Option 03 only. When you input I and Q signals from the rear panel
connectors, set the IQ input signal level to zero externally.
When the spurious emission appears at
the center of the screen with no input
signal, run the center offset calibration.
Figure 4- 8: Center offset
1.
Press the
Cal
key on the front panel (see Figure 4--7).
2. Press the Calibrate Center Offset side key.
The calibration runs. It takes several seconds to complete the process.
When you want to perform the gain, center offset, and DC offset calibration
together, press the Calibrate All side key.
NOTE
. Enabling Auto Calibration (see Figure 4--7) allows the analyzer to run
the center offset calibration automatically when analyzer settings change.
Center Offset Calibration