NF FRA51615, Instruction Manual

Page: 204 / 306

5.9 Error correction
5
-
42
FRA 51615
5.9.6 Open correction
5.9.7 Short correction
For impedance measurements, the open correction function corrects for errors caused by the stray
admittance that remains after the measurement ports are opened and the short correction function corrects
for errors caused by the residual imedance that remains after the measurement ports are shorted. The
following diagrams show the relationship of the admittance and impedance of the DUT (true values,
denoted as Y and Z), and the values measured by this instrument (denoted as Ym and Zm).
(a) Open correction (b) Short correction
Figure 5-23 Operation of the open correction and short correction functions
Open correction subtracts a premeasured stray admittance from the measured admittance. Short correction
subtracts a premeasured residual impedance from the measured impedance. These two types of correction
can be performed independently and at the same time. Because they are similar operations, they are
explained together here.
(a) Open correction (b) Short correction
Figure 5-24 Connections for open correction and short correction
Y
(DUT admittance)
Ym
(measured admittance)
0
0
Ideal
relationship
Actual
relationship
Stray admittance
Z
(DUT impedance)
Zm
(measured impedance)
0
0
Ideal
relationship
Actual
relationship
Residual impedance
Measurement
ports open
FRA51615
CH1 OSC CH2
Current
detection
resistor
FRA51615
CH1 OSC CH2
Current
detection
resistor
Measurement
ports open