Instructions

Page 22
4.4 Setting the Level Attenuator, Amplitude Scale, and Limits
This menu group controls the input attenuator, thus changing the reference level, and controls
the measurement units and scaling of the amplitude display. When option U02 is fitted, it also
enables the sweep amplitude to be compared with limit lines or patterns and the use of level
offset and compensation tables.
4.4.1 Measurement Units and Graticule
sets the measurement units and controls the graticule display. Creates a set of
bottom-row function keys as follows:
provides measurement in dBm (dB milliwatts into 50 Ohms, where 0dBm = 1mW)
and sets the graticule and graticule markings accordingly.
provides measurement in dBuV (dB micro volts across 50 Ohms, where 0dBuV =
1uV) and sets the graticule and graticule markings accordingly.
creates a pop-up menu enabling the Graticule to be dimmed, set to horizontal lines
only, or turned off completely.
Note that, when the measurement units are set to dBuV, the top graticule division is reduced to
7dB in order that subsequent graticule lines correspond to whole decade values.
4.4.2 Reference Level
The reference level represents the maximum signal that can be displayed. The top line of the
graticule is at the reference level unless Scale/Shift is being used (see section 4.4.3).
The reference level is variable between -40dBm (67dB) and +20dBm (127dBuV) to a resolution
of 1dB. It’s current value is displayed in the top annotation area.
the reference level for amplitude measurement can be set either numerically or by
increment/decrement keys:
opens a numeric keyboard from which the reference level can be set directly as a
numeric value in dBm or dBuV.
creates a pop-up menu from which the increment/decrement step size can be set as
1dB, 2dB or 5dB.
increments or decrements the reference level value by the step size set
with the Set Step key.
Units/
Graticule
Ref
Level
Scale/
Shift
Offset/
Tables
Limits
Level/
Limits
Units/
Graticule
dBm
dBuV
Graticule
Ref
Level
Set
Ref
Set
Step
Ref
-
Ref
+