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A40B
Instruction Manual
TVC Sensitivity Characterization
The voltage output of a SJTVC output is proportional to the square of the applied
voltage. Thus the device is inherently non-linear and transresistance gain or
sensitivity changes with input current. Sensitivity characterization minimizes the
resulting errors by determining mean sensitivity in a narrow band ±500 ppm from
the nominal current. Sensitivity characterization is performed before UUT
calibration with the system configured as for UUT measurement (Figure 7).
Figure 9 shows the characterization sequence w
Vin is the setting on the 5730A
Vout_1 , 2 and 3 are the voltages reported by the measuring devices.
The gain factor
the output voltage
The +500 ppm measurement is performed twice to counter drift in the
measurement.
28
Vin_1 = nominal + 500 ppm
Vin_2 = nominal - 500 ppm
Vin_3 = nominal + 500 ppm
η
is a measure of the sensitivity of the device used to measure
Start
Apply Nominal
value + 500 ppm
Delay
Measure Vout
Apply Nominal
value - 500 ppm
Delay
Measure Vout
Apply Nominal
value + 500 ppm
Delay
Measure Vout
End
Figure 9. Characterizing Sensitivity
Δ
Vout
η
=
Gain
factor
Δ
Vin
+
V
V
OUT
_
1
×
2
V
(
in
ppm
)
OUT
=
+
V
V
(
in
ppm
)
IN
_
1
×
2
V
IN
here:
V
in_1
V
out_1
V
in_2
V
out_2
V
in_3
V
out_3
OUT
_
3
−
1
_
2
IN
_
3
−
1
_
2
feh022.eps
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