Tektronix RSA3408B, Service Manual

Page: 106 / 250

Adjustment Procedures
4- 16
RSA3408B Analyzer Service Manual
Self Calibration
Perform these routines to optimize the analyzer performance:
H
Gain calibration
H
Center offset calibration
H
DC offset calibration
Each item is explained in this section.
Equipment
Required
None
Prerequisites Power on the analyzer and allow a 20 minute warm-up before doing
this procedure.
The gain calibration calibrates the analyzer’s amplifier gain using the internal
signal generator. Run this internal calibration routine as required when you boot
the analyzer or when UNCAL (uncalibrated) is displayed during operation.
Allow the analyzer to warm up for 20 minutes before you begin the calibration.
The warm-up period allows the electrical performance of the analyzer to
stabilize.
During normal operation, when the ambient temperature changes by more than

5
°
C from the temperature at the last calibration, UNCAL is displayed in the
yellow box at the top of the screen (see Figure 4--6). If this happens, run the gain
calibration.
UNCAL FREE RUN
Frequency
Span
Input Att
When UNCAL is displayed,
run the gain calibration
Figure 4- 6: UNCAL display
Gain Calibration