3 Spectrum Analyzer Mode
3.3 Channel Power Measurement
Unit Example Notes
dBuA as a Transducer Unit is used when using current probes, because current
probes are often supplied with conversion tables that provide the transducer
factors. When dBuA is used as a Transducer Unit, the normal conversion from
power to amps for dBuA (based on the instrument input impedance) is not done, but
instead the conversion is based solely on the Correction that contains the
transducer factors. This is what distinguishes dBuA as a normal unit from dBuA as a
transducer unit
When querying the Y-Axis unit, you can query the Transducer Unit to distinguish
between regular dBuA and the dBuA Transducer Unit. If :CORR:CSET:ANT?
returns NOC (for No Conversion), you are using a normal Y-Axis dBuA. If it returns
UA, you are using a Transducer Unit dBuA
Amplitude Data Query and Y Axis Unit
The settings of Y-Axis Unit and Display Scale affect how the data is returned over
the remote interface in response to a query. When using the remote interface, no
unit is returned, so you must know what the Y-Axis unit is to interpret the results:
Example 1
Set the following:
–
Display Scale (Log)
–
Y Axis Unit, dBm
–
Scale/Div, 1dB
–
Ref Level, 10dBm
This sets the top line to 10dBm with each vertical division representing 1dB. Thus,
if a point on trace 1 is on the fifth graticule line from the top, it represents 5dBm and
will read out remotely as 5.
Example 2
Set the following:
–
Display Scale (Lin)
–
Y Axis Unit, Volts
–
Ref Level, 100mV (10mV/div)
This sets the top line to 100mV and the bottom line to 0V, so each vertical division
represents 10mV. Thus, if a point on trace 1 is on the fifth graticule line from the
top, it represents 50mV and will read out remotely as 50.
Spectrum Analyzer Mode User's &Programmer's Reference 565