NF ZA57630, Instruction Manual

Page: 164 / 246

4.2 Simple Operation for First Time Use
4
-
6
ZA57630
4.2.2
Measuring Impedance (Measurement Mode: IMPD−EXT)
The IMPD−EXT measurement mode requires current-voltage conversion (current detection
resistor / shunt resistor, current probe, etc.) to be performed for measurement but the
impedance characteristics of a DUT can be measured using a high voltage or high current,
which is not possible with general impedance analyzers. This is achieved by amplifying the
measurement signal of this instrument using a DUT drive amplifier. Furthermore, since a
measurement connection appropriate for the DUT is possible, impedance characteristic of a
DUT with grounding can also be measured.
■ Example impedance measurement connection of DUT using large voltage
Connect the voltage of the DUT to
PORT1
and connect the voltage resulting from converting
the current flowing to the DUT to
PORT2
.
Figure 4-1 Impedance Measurement Connection Example 1 (IMPD
−EXT, Measurement of High Voltage)
The above connection allows you to obtain the value of imp current detection
resistance of the DUT as the measurement result. The influence of the probe and current
detection resistor can be removed by short correction and load correction. For details on short
correction and load correction, refer to
“1.8 Error Correction”
in
Instruction Manual (Advanced)
.
When the measurement signal output is amplified by a DUT drive amplifier (power amplifier), the
impedance characteristics of a DUT can be measured using a high voltage that exceeds the signal
amplitude of this instrument (maximum 3 Vrms). When taking the measurement, use, for example,
a probe for an oscilloscope or a differential probe so that the signal amplitude input to
PORT1
will
be no higher than 10 Vrms. Use a current detection resistor, CT, current probe, etc. to convert the
current flowing to the DUT to a voltage and then measure the voltage at
PORT2
.
Setting the gain of the DUT drive amplifier in
[OSC]
－
[POWER AMP GAIN]
enables the
signal amplitude to apply to the DUT to be directly set on this instrument. For details, refer
to
“4.3 Setting Measurement Signals”.
If the reciprocals of the conversion ratio for conversion using a probe or current detection
resistor are set in
[Range]
－
[WTG FAC PORT1]
and
[WTG FAC PORT2]
respectively, the value
equivalent to a DUT voltage/current will be converted and then displayed on this instrument.
For details, refer to
“1.8.2 Weighting Factor”
in
Instruction Manual (Advanced)
.
Current detection resistor
Rs
i
Rs i
OSC / H
CUR
PORT1 / H
POT
PORT2 / L
CUR
DUT drive amplifier
DUT
Zx
10:1 probe
v
0.1 v
ZA57630