13 | Keysight | 4285A Precision LCR Meter – Data Sheet
Measurement Accuracy Calculation Example
Example of L -Q accuracy calculation
s
Measurement conditions
Measured inductance Lx of DUT:
Measured Q value of DUT:
Test signal level:
Test frequency fm:
Integration time:
220 nH
30
1 Vrms
25.2 MHz
LONG
0 m
Cable length:
Operating temperature:
28 °C
Determine inductance measurement accuracy A
e
1. From |Z|, |Y|, L, C, R, X, G, and B Accuracy (see page 6), measurement accuracy Ae is
determined as below:
Ae = ± ( An + Ac ) x Kt
2. First of all, to determine the measurement accuracy Ae, calculate the impedance value
from the DUT’s inductance value. So the measurement impedance Zm is:
Zm = 2 πfmLx
≈ 35 [Ω]
where:
fm = Test frequency [Hz]
Lx = Measured inductance value of the DUT [H]
3. Choose an accuracy chart from Figure 1-3 and Figure 1-4. The oscillator level is
1 Vrms, then Figure 1-3 is chosen for this measurement.
4. Find the frequency point of fm (25.2 MHz) along the X axis in Figure 1-3. Both axes are
in log format. Interpolation may be required.
5. Find the impedance point of Zm (35 Ω) along the Y axis in Figure 1-3 determined in
step 2. Both axes are in log format. Interpolation may be required.
6. Mark the intersection of above two steps and determine the basic accuracy equation
An, integration factor Ki, and oscillator level factor Kosc
.
From:
Test frequency fm: 25.2 MHz
DUT’s impedance Zm: 35 Ω
Integration time: LONG
Test signal level: 1 Vrms
Then,
An = A1, Ki = 1, and Kosc = 1 (rounded from 0.02).
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