Keithley 2000, User Manual, Page: 213 / 280

SCPI Command Reference 5-75
:DB:REFerence <n>
:UNIT:VOLTage:AC:DB:REFerence <n> Specify dBm reference
Parameter
<n> = le-7 to 1000 Specify reference in volts
Query
:REFerence?
Description
This command is used to specify the dB reference level. When DB units is
selected (:VOLTage:AC: DB), ACV db measurements are made using the
specified dB reference level.
The reference level is specified in volts and is not range dependent. For ex-
ample, a dB reference level of 1 is 1V on all ACV measurement ranges.
:DBM:IMPedance <n>
:UNIT:VOLTage:AC:DBM:IMPedance <n> Specify dB reference
Parameter
<n> = 1 to 9999 Specify reference impedance
Query
:IMPedance?
Description
This command is used to specify the dBm reference impedance level. When
dBm units is selected ACV dBm measurements are made using the specified
dBm reference impedance.
The reference impedance is specified in ohms and is not range dependent.
For example, a dBm reference level of 600 is 600 on all ACV measurement
ranges. A rational number is rounded to the nearest valid integer value.
[:DC] <name>
:UNIT:VOLTage:DC <name> Specify DCV units
Parameters
<name> = V DC voltage measurement units
DB dB DC voltage measurement units
DBM dBm DC voltage measurement units
Query
[:DC]? Query DC voltage units
Description
This command is used to select the units for DCV measurements. With volt
(V) units selected, normal DC voltage measurements are made for the DCV
function. With DB units selected, DC dB voltage measurements are per-
formed. The DBM units selection is used to make decibel measurements ref-
erenced to 1mW. dB and dBm measurements are explained further in
Section 2.