User manual

Front Panel Operation
2001-900-01 Rev. K/ August 2010 3-41
Trigger level
The frequency function has an adjustable trigger level. An
appropriate trigger level is needed for the frequency counter
to operate properly. The instrument only counts cycles with
peak amplitudes that reach the trigger level. For example, if
the trigger level is set for 5V, cycles with peak amplitudes
less than 5V are not counted.
If using AC+DC coupling, make sure the trigger level
accounts for the DC bias level. For example, if a 1V peak-to-
peak input signal is riding on a 5V DC bias level, a trigger
level of 5.5V is appropriate.
While the display is showing frequency measurements, the
RANGE  and  keys can be used to change the trigger
level of the measurement.
Each press of a RANGE  or  key adjusts the trigger level
by 0.5% of the presently selected maximum signal level to a
maximum of 60% of the range. The AUTO RANGE key
returns the trigger level to 0V or 0mA. After pressing one of
the range keys, the present trigger level is momentarily
displayed. The trigger level is also available as a multiple
display.
See Table 3-21 for the trigger level ranges and increments.
Frequency configuration
The following paragraphs detail how to change the Model
2001 from its bench reset conditions for frequency
measurements. The configuration menu is summarized in
Table 3-22. Note that a function does not have to be selected
in order to be configured. When the function is selected, it
will assume the programmed status.
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Frequency measurements
NEXT
DISPLAY
PREV
POWER
DCV ACV DCI ACI Ω2 Ω4
FREQ TEMP
REL TRIG STORE RECALL
INFO LOCAL CHAN SCAN CONFIG MENU EXIT ENTER
RANGE
AUTO
FILTER MATH
RANGE
2001 MULTIMETER
SENSE
Ω 4 WIRE
HI
INPUT
LO
INPUTS
CAL
500V
PEAK
F
R
FRONT/REAR
2A 250V
AMPS
350V
PEAK
1100V
PEAK
Model 2001
Caution : Maximum Input = 1100V peak, 2 x 10
7
V•Hz
AC Voltage
Source
A. AC Voltage Input
NEXT
DISPLAY
PREV
POWER
DCV ACV DCI ACI Ω2 Ω4
FREQ TEMP
REL TRIG STORE RECALL
INFO LOCAL CHAN SCAN CONFIG MENU EXIT ENTER
RANGE
AUTO
FILTER MATH
RANGE
2001 MULTIMETER
SENSE
Ω 4 WIRE
HI
INPUT
LO
INPUTS
CAL
500V
PEAK
F
R
FRONT/REAR
2A 250V
AMPS
350V
PEAK
1100V
PEAK
Model 2001
Caution : Maximum Input = 1A peak
AC Current
Source
B. AC Current Input
+000.00 mHz
Terminals: VOLT Coupling: AC
+000.00 mHz
Terminals: CURR Coupling: AC
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Trigger level range and increments
Maximum
signal level
Trigger level
Range Increment
1V
10V
100V
1000V
-0.600 to +0.600V
-6.00 to +6.00V
-60.0 to +60.0V
-600 to +600V
0.005V
0.05V
0.5V
5V
1mA
10mA
100mA
1A
-0.600mA to +0.600mA
-6.00mA to +6.00mA
-60.0mA to +60.0mA
-600mA to +600mA
0.005mA
0.05mA
0.5mA
5mA
Note: The trigger level for TTL triggering defaults to +0.80V.