HP ESA-L1500A, Руководство пользователя и калибровки

Страница: 88 / 326

Chapter 4 87
Front-Panel Key Reference
Measure
Measure
Measure
accesses softkey menus that edit limit line functions (
Limits
),
determine the N dB bandwidth of a signal (
N dB Points On Off
),
determine % AM of a signal (
% AM On Off
), and determine third-order
intercept (
TOI On Off
).
Limits
accesses the following
Limits
menu keys. Limit lines can be created by
the user to test trace data. A limit line is a test limit made up of a series
of line segments, positioned according to frequency and amplitude
within the measurement range of the spectrum analyzer. There can be
one upper limit line and one lower limit line which set maximum and
minimum test limits.
Limit Display Y N Auto
displays any portion of the limit lines that are currently
within the spectrum analyzer display boundary. If
Y
(yes) is underlined, the limit lines are displayed. If
N
(no) is underlined, they are not displayed. If
Auto
is
underlined, the display of the limit lines is dependent
on
Limit Test On Off
. The limit lines will be displayed
while the limit test function is turned on, otherwise
they will be turned off. Key Access:
Measure
,
Limits
Limit Test On Off
turns the limit line testing and (if
Limit Display Auto
is
selected) the display of the limit lines on and off. When
limit line testing is enabled, every measurement sweep
of trace A is compared to the limit lines. If trace A is at
or within the bounds of the limit lines,
LIMIT PASS
is
displayed. If trace A is out of the limit line boundaries,
LIMIT FAIL
is displayed. Key Access:
Measure
,
Limits
X Axis Units Freq
Time
selects whether limit lines will be entered using
frequency or sweep time to define the segments. They
can be specified as a table of limit line segments of
amplitude versus frequency, or of amplitude versus
time. Time values are evaluated with respect to the
spectrum analyzer sweep time. A time value of zero
corresponds to the start of the sweep, which is at the
left edge of the graticule.
Switching the limit line definition between frequency
and time will erase the current limit line table. The
message
If you are sure, press key again to
purge data
will appear. Press
X Axis Units Freq Time
again to purge the limit line table and switch between
frequency and time. Key Access:
Measure
,
Limits