Instructions

Page 19
4.5 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 U01 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.
4.5.1 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.
4.5.2 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 4.5.3).
the reference level for amplitude measurement is changed by switching the
attenuators. Creates a set of bottom-row function keys as follows:
sets the reference level to 0dBm (or 107dBuV) by setting the attenuator to On. The
setting is shown within the upper area of the screen.
sets the reference level to -20dBm (or 87dBuV) by setting the attenuator to Off. The
setting is shown within the upper area of the screen.
Units/
Graticule
Ref
Level
Scale/
Shift
Offset/
Tables
Limits
Level/
Limits
Ref
Level
Units/
Graticule
dBm
dBuV
Graticule
0dBm
-20dBm