HP 70000 series, User Manual

Page: 93 / 447

Functional Grouping Denitions
Preselector Functions
The preselector functions are available when a preselector module or RF section with
preselector capabilities is installed in the system. T o make preselected measurements , be
sure the input port on the preselector module is active . Select the active input port with the
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select input softkey .
The analyzer may require recalibration for measurements made with another input port. Refer
to the \Calibration Functions" section in this chapter for more information.
Programming-Related Functions
The programming-related softkeys provide various functions for programming from the front
panel, troubleshooting programs , and editing user-dened functions .
Service-Related Functions
The service-related softkeys provide various functions for checking analyzer operation, clearing
all instrument memory , and modifying the sweep range of the local oscillator .
Signal-Detection Functions
The spectrum analyzer is an analog receiver that translates a detected analog signal into a
series of amplitude values , called elements . An interval of time passes while the analyzer
sweeps and detects the analog signal. If one sweep of trace data is divided into 800 increments
of time , the spectrum analyzer produces 800 trace elements .
The signal-trace detection functions determine how the analyzer chooses one amplitude value
for each element from the many amplitude values detected during one of these intervals of
time .
Signal-Identication Functions
The signal-identication functions distinguish real signals from image or harmonic responses .
Two signal-identication methods are available , called shift and image . The image and shift
methods test a signal that is marked by the active marker . If a marker is not present, they
mark the highest signal peak automatically before beginning the identication process .
Signal-P ath Functions
The signal-path functions select the input port and its type of coupling, ac or dc . They also
control the signal path through and between modules installed in the system.
Sweep and Trigger Functions
The sweep and trigger functions adjust sweep time and signal triggering. Whenever a sweep is
in progress , the \MEASURE" indicator on the front of the HP 70900B local oscillator source is
lit. The indicator is o between sweeps and frequency bands .
3-26 SoftK ey Quick Reference