COM-power corporation CLCI-400, Instruction Manual

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Page 17 of 30
INSTRUCTION MANUAL
SEC TI ON 4
- CALIB RATION
Rev081219
The insertion loss of a current probe, at any given frequency quantifies the
difference between the voltage quantity delivered to the probe’s input
port and the voltage quantity induced onto the center conductor of the
test fixture into which the probe is installed.
For a current monitor probe, a known voltage is applied into one side of the
calibration fixture, with the opposite side terminated into 50 ohms; while
measuring the voltage present at the output of the probe. The difference
between the applied voltage and the measured voltage, at any given
frequency, is the insertion loss of the probe.
For an injection probe, a known voltage is applied to the input port of the
probe, while measuring the voltage present on one side of the calibration
fixture, with the opposite side terminated into 50 ohms. Again, the
difference between the applied voltage and the measured voltage, at
any given frequency, is the insertion loss of the probe.
Shown in Figure 11 are two equivalent schematic circuits for the two
respective measurement methods. The physical test setup showing the
equipment and connections is illustrated in Figure 12.
As measured in either of the circuits shown in Figure 11, the following
equation defines the insertion loss of the probe, at any given frequency:
NOTE:
Typical Insertion Loss Values for the CLCI-400 are represented in Figure 5
(Section 3.7).