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GETTING STARTED
2. When measuring sinusodial
waveforms,
the sampling
by the sampling
interval.
Fur example, the period of a
frequency must be greater than twice the frequency you
IkHz signal is l/lOOO=lmsec.
With a 50~s~ sampling
are measuring, or aliasing will occur. For example, with
interval,
the required
number
of samples is ~lmseci
a 6OHz sine wave you might choose a sampling frequen-
5O~sec=20 samples.
cy of 150 or 200Hz. Since non-sinusodial
waveforms are
generally rich in harmonics, a good rule of thumb is to
4. The type of coupling will depend on whether or not you
select a sampling frequency of at least 20 times the fre-
wish to remwe the DC component
from a waveform.
quency of the periodic waveform. For example, with a
To measure a pure DC signal, you \wuld
<>bviousl\
2kHz rectangular wave, a sampling frequency of at least
select DC coupling.
For d synumctrical
sine \vInr.
,\i
40kHz should be chosen.
coupling
could be used to removt' JIIY SIIUII DC uffwt
that might be present in thr wa\wfo;m.
3. The programmed
number of samples will depend on
the frequency
of the signal you are measuring,
the
5. The m.~thematical function you USC' ~vill depend on \CU!
sampling
rate, as well as how many cycles of the
analysis requirements. For DC voltages the .wrr.lg' ilmc~
waveform you wish to capture. You can dctcrminc
the
tion (along with the default 166.7~wc, 101 samples) is
recommended to minimize 601Hz AC noise eifects on the
required number of samples required to measure one
complete cycle by dividing
the period of the waveform
measurcmcnt.
(If operating the unit on 5tlt Iz puwer, the
sampling
interval
should be 200,rscc.).
Table 2-5. Recommended
Operating
Modes For Typical Waveforms
Waveform
-~
~=15734Hz
SAWTOOTH WAVEFORM
Range
32V
32v
3.2V
2oov
ampling
hItend
lmsec
50rsec
3LLsec
*Math function
depends on required waveform
analysis
# Samples
100
20
25
COllpling
DC
AC
DC
DC
Math Function'
Aver'lgr
TRMS
Peak
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