Agilent Technologies 8590 Series Service Manual page 575

COARSE TUNE DAC Coarse Tune DAC
D Displays the analog output of the YTO coarse-tune
ESCRIPTION
DAC located on the A7 analog interface assembly. The
mnemonic for the control voltage is C_TUNE.
When
is displayed in the lower four divisions of the screen.
The line represents the 0 V to −10 V DAC output
voltage. When the YTO DAC voltage becomes more
negative, the YTO frequency is increased, and the
displayed line moves lower on screen.
Refer to
information.
R S
ELATED OFTKEYS
CONF TEST Confidence Test
D This test automates an informal, visual test that
ESCRIPTION
quickly checks the basic operation of six IF and video
functions. Each test checks for a simple change in
signal position when the analyzer settings for the
function under test are changed. Instrument
specifications are not used as test limits.
If a test failure occurs, the error message CONF TEST
FAIL is displayed along with error messages for the
failed test. Each check and its corresponding error
message are described below.
1. Positive-Peak Detector Check and error message
POS-PK FAIL.
The test checks switching for the positive-peak
detector. The noise-floor level should increase when
switching from the sample detector to the
positive-peak detector.
The test detects the noise-floor increase by
statistically comparing the level of the noise floor for
the positive-peak detector to the level for the sample
detector.
Chapter 13
COARSE TUNE DAC
Chapter 6 for additional LO troubleshooting
FINE TUNE DAC
Softkey Descriptions
Softkey Descriptions
is selected, a horizontal line
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