Agilent Technologies E4440A User Manual

Chapter 2 47
Instrument Functions: A - L
AMPLITUDE / Y Scale
Instrument Functions: A - L
2.1.9 Ref Lvl Offset
Allows you to add an offset value to the displayed reference level. The reference level is the
absolute amplitude represented by the top graticule line on the display. Reference-level
offsets are entered by using the numeric keypad or programming commands. The knob and
step keys are not active.
Offsets are used when gain or loss occurs between a device under test and the analyzer
input. Thus, the signal level measured by the analyzer may be thought of as the level at
the input of an external amplitude conversion device. Entering an offset does not affect the
trace position or attenuation value, just the displayed value readouts such as reference
level and marker amplitudes.
The maximum reference level available is dependent on the reference level offset. That is,
Ref Level
− Ref Level Offset must be in the range −170 to +30 dBm.
For example, the reference level value range can be initially set to values from
−170 dBm
to 30 dBm with no reference level offset. If the reference level is first set to
−20 dBm, then
the reference level offset can be set to values of
−50 to +150 dB.
If the reference level offset is first set to
−30 dB, then the reference level can be set to
values of
−200 dBm to 0 dBm. In this case, the reference level is “clamped” at 0 dBm
because the maximum limit of +30 dBm is reached with a reference level setting of 0 dBm
with an offset of
−30 dB. If instead, the reference level offset is first set to 30 dB, then the
reference level can be set to values of
−140 to +60 dBm.
When a reference level offset is entered, the offset value appears on the left side of the
display under Offst (as opposed to frequency offsets which appear at the bottom of the
display.) To eliminate an offset, press
Ref Lvl Offst, 0, and dB.
Key Path:
AMPLITUDE / Y Scale
Key Notes: Only numeric entries are valid, the knob and step keys are not applicable
to this function.
Annunciation/
Annotation: The offset is displayed to left of Trace window; third from the top, just
below the scale type.
State Saved: Saved in Instrument State
Factory Preset: 0.0 dB
Range: –327.6 dB to 327.6 dB

Agilent Technologies E4440A Specifications

General

Brand	Agilent Technologies
Model	E4440A
Category	Measuring Instruments
Language	English