87 V/AN
Service Manual
8
Table 8. Frequency Counter Sensitivity and Trigger Levels
Minimum Sensitivity (RMS Sine wave)
Input Range
1
5 Hz - 20 kHz
0.5 Hz - 200 kHz
Approximate Trigger
Level
(DC Voltage Function)
600 mV dc
600 mV ac
6 V
60 V
600 V
1000 V
70 mV (to 400 Hz)
150 mV
0.3 V
3 V
30 V
100 V
70 mV (to 400 Hz)
150 mV
0.7 V
7 V (
≤
140 kHz)
70 V (
≤
14.0 kHz)
200 V (
≤
1.4 kHz)
40 mV
1.7 V
4 V
40 V
100 V
Duty Cycle Range
Accuracy
0.0 to 99.9 %
Within
±
(0.2% per kHz + 0.1 %) for rise times < 1
µ
s.
1. Maximum input for specified accuracy = 10X Range or 1000 V.
Table 9. Electrical Characteristics of the Terminals
Function
Overload
Protection
1
Input Impedance
(nominal)
Common Mode
Rejection Ratio
(1 k
Ω
unbalance)
Normal Mode Rejection
L
1000 V rms
10 M
Ω
< 100 pF
> 120 dB at dc,
50 Hz or 60 Hz
> 60 dB at 50 Hz or 60 Hz
F
mV
1000 V rms
10 M
Ω
< 100 pF
> 120 dB at dc,
50 Hz or 60 Hz
> 60 dB at 50 Hz or 60 Hz
K
1000 V rms 10 M
Ω
< 100 pF (ac-
coupled)
> 60 dB, dc to 60 Hz
Full Scale Voltage
Typical Short Circuit Current
Open Circuit
Test Voltage
To 6.0 M
Ω
50 M
Ω
or
60 nS
600
Ω
6 k
60 k 600 k 6 M 50 M
e
1000 V rms
< 7.5 V dc
< 4.1
V dc
< 4.5
V dc
1 mA 100
µ
A 10
µ
A 1
µ
A 1
µ
A 0.5
µ
A
G
1000 V rms
< 3.9 V dc
3.000 V dc
0.6 mA typical
1. 10
6
V Hz max
Table 10. MIN MAX Recording Specifications
Nominal Response
Accuracy
100 ms to 80 %
(dc functions)
120 ms to 80 %
(ac functions)
250
µ
s (peak)
1
Specified accuracy
±
12 counts for changes > 200 ms in duration
Specified accuracy
±
40 counts for changes > 350 ms and inputs > 25 % of range
Specified accuracy
±
100 counts for changes > 250
µ
s in duration
(add
±
100 counts for readings over 6000 counts)
(add
±
100 counts for readings in Low Pass mode)
1. For repetitive peaks: 1 ms for single events.
