HP 8924E, Assembly

Page: 585 / 640

585
Chapter 14, Diagnostics Descriptions
Description of RF Diagnostics (RFDIAGS3)
N:\mkt\MANUALS\HP8924C\ALR\diagnos.fb
Output A26
Table 125 A26 Output Tests
Measurement Explanation and Suggestions Measurement Point
+8 V Power
Supply The +8 Vdc supply generated on the Output assembly
is measured. The voltage measured by the DVM is the
actual voltage divided-by-2. DVM:OUT_POS_8V
−
6 V Power
Supply
The
−
6 Vdc supply generated on the Output assembly
is measured. The voltage measured by the DVM is the
actual voltage divided-by-2.
DVM:OUT_NEG_6V
Amplifier Bias
Voltage The bias voltage is measured on the output amplifier. DVM:OUT_AMP_BIAS
Carrier Level
DAC The carrier level DAC is checked by turning on each
bit, one at a time, and measuring the voltage output
with each bit turned on. It is also checked with all bits
on. The limits are calculated based on the actual volt-
age measured for the
−
6 V supply in a previous test.
The bit value (B) is calculated as (
−
6 V actual)
×
4
÷
6
÷
4096.
DVM:OUT_LEVEL_REF
Filter Tune
DAC The Filter Tune DAC is checked by turning on each
bit one at a time and measuring the voltage output
with each bit turned on. It is also checked with all bits
on. The limits are calculated based on the actual volt-
age measured for the
−
6V supply in a previous test.
The bit value (B) is calculated as -1
×
(
−
6 V actual)
×
2
×
422
÷
984
÷
4096.
DVM:OUT_TUNE_FILTER
Open Loop ALC
Drive This test opens the ALC Loop and checks that the
voltage from the Level DAC appears at the modula-
tor, input. The carrier level DAC is set to 4095 (full
scale). The nominal output of the DAC (Ref) is calcu-
lated based on the actual voltage measured for the
−
6
V supply in a previous test. Ref =
−
1
×
(
−
6 V actual)
×
4
÷
6
×
100
÷
75
×
4095
÷
4096.
DVM:OUT_ALC_DRIVE