Keysight Technologies X Series Service Manual page 84

Self Test
Self Test Descriptions
1103 MW ALC Level
This test checks the ALC Level DAC and related circuitry.
1104 MW ALC Modulation HB
This test checks the High-Band ALC modulation driver circuitry. This test runs
in open-loop mode so that the integrator will not contribute to this test. In
addition, the RF is turned OFF during this test using the pulse modulator;
otherwise, peak RF power would be present throughout the RF chain while this
test is running.
1105 MW ALC Detector
This test checks both the Low-band and High-band ALC detectors by applying
RF power through the three main signal paths. This test is performed in
open-loop mode so that the ALC does not try to correct, thereby influencing
the measurements. The frequency is set to select the desired RF path and
associated ALC detector.
1106 MW ALC Power Limit
This test checks the MW ALC Power Limit and Clamping circuitry. This test is
performed in open-loop mode. During this test, the RF power is adjusted to
achieve an ALC detector voltage of -1.2V by adjusting the MW ALC Level DAC.
The Power Clamping circuit operates as a secondary ALC loop that activates
when the ALC detector level reaches the Power Limit DAC output. Above this
level, the Power Clamp output will drive the ALC Mod Driver to prevent the ALC
detector level from going more negative (higher power level) than set by the
Power Limit DAC setting.
1107 MW ALC Logger
This test checks the MW ALC logger circuitry. This test is performed in
open-loop mode. During this test, the RF power is adjusted to achieve a
certain ALC detector voltage by adjusting the RF ALC MOD Offset DAC to get a
known voltage into the logger circuit. The slope of the logger is measured at
the high, mid, and low end of the ALC detector range.
1108 MW ALC Detector Offset
This test checks that the ALC Detector Offset DAC can properly adjust the ALC
Logger Circuitry. This test is performed in open-loop mode. The ALC Detector
Offset DAC compensates for the ALC detectors offset, which mostly affects the
low power range. Therefore, the RF power is set low for an ALC Detector
voltage of -0.15V by adjusting the ALC MOD Offset DAC.
1109 MW ALC BulkR
This test checks that the ALC Bulk R DAC can properly adjust the ALC logger
circuitry. This test is performed in open-loop mode. The Bulk R DAC
compensates for the Low Amp's transistor equivalent resistance that would
84 Keysight CXG, EXG, and MXG X-Series Signal Generators Service Guide