Limit-Line Functions; Editing, Creating, Or Viewing A Limit-Line; Selecting The Type Of Limit-Line Table - HP 8590 E-Series User Manual

Limit-Line Functions

This section describes the limit-line functions in the order that they are usually used.

Editing, Creating, or Viewing a Limit-Line

Pressing (j-1, then Limit Lines accesses the softkey menus used for creating a limit line.
Press Edit Limit to edit an existing limit-line table or. If no limit-line table currently exists
this will allow you to create one.
If a limit line exists currently, and you would like to purge it and create a new one, press
Edit Upper, and More 1 of 2 . Then press PURGE LIMITS two times to clear the existing
limit-line table and access the limit-line editing menu.
Note
After pressing PURGE LIMITS the first time, the message If you are sure,
press key again to purge data will appear. Pressing PURGE LIMITS a second
time purges the limit-line table. (jZK7) turns limit-line testing off (if it is on),
but does not clear an existing limit-line table.
Selecting the Type of Limit-Line 'lkble
The LIMITS FRq TIME key selects the type of limit line parameters. Parameters can
be entered as frequency/amplitude coordinates, or as time/amplitude coordinates. Use
the LIMITS FRq TIME key, to underline the desired choice of either frequency or time
parameters. Frequency is the default selection. If TIME is selected SELECT TIME will replace
SELECT FREq in the Edit Limit menus.
The second column of the limit-line table is labeled START-FREQ when frequency is selected.
It is labeled START-TIME when time is selected.
The LIMITS FIX REL key selects the type of limit line. There are two types of limit lines:
fixed and relative. Fixed limit lines contain only absolute amplitude and frequency (or time)
values. Relative limit lines consist of frequency values that are referenced to the spectrum
analyzer center frequency and amplitude values that are relative to the analyzer reference
level. The relative setting does not affect time values. They always begin at the left edge of
the graticule.
As an example fixed versus relative limit lines, if a limit line is specified as fixed, entering a
limit-line segment with a frequency coordinate of 300 MHz displays the limit-line segment at
300 MHz. If the same limit-line table is specified as relative, it is displayed relative to the
spectrum analyzer center frequency and reference level. If the center frequency is at 1.2 GHz,
a relative limit-line segment with a frequency coordinate of 300 MHz will display the limit-line
segment at 1.5 GHz. If the amplitude component of a relative limit-line segment is -10 dB and
the spectrum analyzer reference level is -15 dB, then -10 dB is added to the reference-level
value and the amplitude component of the limit line will be at -25 dB.
RELATIVE is displayed in the limit-line table when the limit-line type is relative; FIXED is
displayed when the limit-line type is fixed. A limit line entered as fixed may be changed to
relative, and one entered as relative may be changed to fixed. When the limit-line type is
changed, the frequency and amplitude values in the limit-line table are modified by the current
center frequency and reference level settings to keep the limit line in the same position on the
spectrum analyzer.
5-22 Using Analyzer Features