tab of the Connection
Control menu; refer to Chapter 4 in this manual or in the manuals for
the relevant network options. The purpose of the RF user correction is to compensate for an inevitable frequency and level-dependent attenuation in the test setup (frequency and level response correction). Level correction values are determined by means of a signal generator or power meter connected to the CMU’s input and output ports and stored to a file, which is transferred to the CMU in order to modify its RF generator level and to correct its RF analyzer results.
The correction values must be acquired independently for the input and output connectors of the instrument.
Note:
In addition to the RF user correction described here, the instrument provides
a frequency-dependent input and output attenuation for each function group.
The frequency-dependent attenuation is defined in the RF tab of the Connection
Control menu; refer to Chapter 4 in this manual or in the manuals for
the relevant network options.
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Output level correction |
The correction values for output signals (connectors RF1, RF2 or RF3 OUT) modify the RF generator level so that the actual RF signal power at the input of the DUT is equal to the nominal RF generator level.
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Input level correction |
The correction values for input signals (connectors RF1, RF2 or RF4 IN) modify the measured analyzer level so that the result for the RF signal power is equal to the power transmitted by the DUT.
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Once the correction tables have been transferred to the instrument, the RF user correction is an internal procedure. There are several advantages of using this internal correction method rather than post-processing the CMU results by means of an external measurement program:
The input level correction affects all acquired RF power results including derived quantities (e.g. the results of the limit check) without slowing down the speed of the measurements. Evaluating derived quantities by means of an external program can be tedious. The RF user correction ensures that all results, including the derived ones, are consistent. Exception: The wideband power, which is provided in the Analyzer/Generator menu of the RF function group and in many network test applications, is always uncorrected.
The user correction is included in all results displayed in the measurement menus.
Correction data can be acquired individually for each instrument and stored to its internal hard disk. If several testers are used in a production measurement system, the individual units are independent from each other and interchangeable.
Compiling
and Loading User Correction Tables
File Format
for User Correction Tables
Ranges of Values
and Limitations
