2620A/2625A
Users Manual
D-2
AC Signal Cross Talk Into an AC Voltage Channel
ACV Error Ratio =
VACrms error
VACrms crosstalk Frequency crosstalk
()
() ()×
Range Ratio (worst case) Ratio (typical)
×
vHz×
×
vHz×
×
vHz×
×
vHz×
30.000 V 1.2× 10
-6
vHz×
2.6× 10
-7
vHz×
150.00/300.00 1.2 × 10
-5
vHz×
3.4× 10
-6
vHz×
For example, to find the typical effect of a 60 Hz, 220V ac signal on another channel for
the 300 mV range, you would calculate: 220 X 60 X 1.4 X 10
-8
= 0.18 mV.
AC Signal Cross Talk Into an Ohms Channel
AC Frequency = 50, 60 Hz, ±0.1%
OHMS Error Ratio
1
=
Ohms error
VACrms crosstalk
()
()
Range Ratio (worst case) Ratio (typical)
×
Vrms
3.0000 ke
2.4
×
rms
×
rms
30.000ke 3.1× 10
-
4
Vrms
8.4× 10
-5
Vrms
300.00 ke 5.6× 10
-3
kOhms
Vrms
3.7× 10
-3
kOhms
Vrms
3.0000 Me 3.8 × 10
-4
MOhms
Vrms
3.8× 10
-5
MOhms
Vrms
10.000 Me 1.4 × 10
-3
MOhms
Vrms
4.3×
MOhms
Vrms
For example, to find the typical effect of a 60 Hz, 100V ac signal on another channel for
the 30 kΩ range, you would calculate: 100 X 8.4 X 10-5 = 0.008 kΩ.
AC Signal Cross Talk Into a Frequency Channel
Frequency measurements are unaffected by cross talk as long as the voltage-frequency
product is kept below the following limits:
Worst Case Typical
V x Hz Product Limit 3.7 × 10
4
(V × Hz) 1.0 × 10
6
(V × Hz)
These values assume no more than 1000 pf of capacitance between either end of the resistor (HI and LOW ) and
earth ground.
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