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3.5 Measuring Frequency and Period
Model TH1941 frequency measurement range: 5 Hz to more than 1MHz.
Model TH1941 period measurement range: 0.2s to less than 1
μ
s.
Input signal range: 200 mV AC to 750V AC.
The instrument uses the volts input terminals to measure frequency. The AC voltage range can be
changed with the RANGE
and
keys. However, the signal voltage must be greater than
10% of the full-scale range.
3.5.1 Trigger Level and Measurement Errors
Model TH1941 uses a technique which maintains a constant resolution for any input frequency to
measure frequency and period. The gate time is always a multiple of the measured signal period rather
than a fixed time. The error will be no more than +/-1 from the total gate counts, this assures an
equivalent accuracy over the whole frequency range.
3.5.2 Gate Time
Gate time is the amount of time TH1941 uses to sample frequency or period readings. The
measurement speed rate and the measuring frequency change the gate time.
3.5.3 Connections
Assuming Model TH1941 is under factory default conditions, the basic procedure is as follows:
1. Connect test leads to
and COM terminals.
2. Select frequency or period measurement functions by pressing
Freq
or
Shift
→
Freq
3. Connect test leads to the source as shown in Figure 3-4:
CAUTION: Do not exceed 1000V peak between
and COM, or instrument damage may
occur.
4. Taking a reading from the display
！
CAT
Ⅰ
(
1000V
)
CAT
Ⅱ(
300V
)
Ω
COM
20A
T1AL 250V
ALL INPUT
1KV MAX
500mA
MAX
V
1000V
MAX
DC I
AC I
Period
dB
dBm
%
Comp
Hold
Menu
Local
2nd
DC V
AC V
Ω
Freq
AC+DC
Rel
Rate
Esc
Shift
Trig
Auto
mA
4 Digit Multimeter
TH1941
1
2
POWER
ON
OFF
AC VOLTAGE
SOURCE
MED
AUTO
Frequency Measurement
