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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 show levels
only, or turned off completely.
4.5.2 Reference Level
the reference level for amplitude measurement is changed by switching the
attenuator On or Off. 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.
4.5.3 Vertical Scaling
enables the vertical amplitude scaling to be changed. Creates a set of bottom-row
function keys as follows:
creates a pop-up menu enabling the vertical scaling to be set to 10dB/div (the
default) through to 1dB/div.
For scales below 10dB/div only a portion of the sweep amplitude will be
visible and the Shift Up/Shift down keys can be used to pan the trace
through the amplitude range of the graticule. These keys auto-repeat.
Units/
Graticule
Ref
Level
Scale/
Shift
Offset/
Tables
Limits
Level/
Limits
Ref
Level
0dBm
-20dBm
Scale/
Shift
Scale
Shift
Down
Shift
Down
Units/
Graticule
dBm
dBuV
Graticule