Fluke 2620A User Manual

Page of 197
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)
×
v
Hz
×


×
v
Hz
×


×
v
Hz
×


×
v
Hz
×


30.000 V
1.2
×
10
-6
v
Hz
×


2.6
×
10
-7
v
Hz
×


150.00/300.00 1.2
×
10
-5
v
Hz
×


3.4
×
10
-6
v
Hz
×


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)
×
Ohms
Vrms




3.0000 k
e
2.4
×
Vrms


×
Vrms


30.000k
e 3.1
×
10
-
4
kOhms
Vrms




8.4
×
10
-5
kOhms
Vrms




300.00 k
e
5.6
×
10
-3
kOhms
Vrms




3.7
×
10
-3
kOhms
Vrms




3.0000 M
e
3.8
×
10
-4
MOhms
Vrms




3.8
×
10
-5
MOhms
Vrms




10.000 M
e
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 k
Ω
 range, you would calculate: 100 X 8.4 X 10-5 = 0.008 k
Ω
.
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
 (
×
 Hz)
1.0 
×
 10
6
 (
×
 Hz)
These values assume no more than 1000 pf of capacitance between either end of the resistor (HI and LOW ) and
earth ground.