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IM 701240-01E
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App
Index
Explanation of Functions
2.2
Setting the Horizontal and Vertical Axes
Horizontal (Time) Axis «For procedures, see section 5.2.»
Record Time
When using the internal clock*, the time axis scale is set using the length of time within
one screen. The record time is the length of time within one screen. The record time is
set in units of second, minute, hour, and day. The transition from seconds to minutes to
hours to days is automatically performed. The selectable record time varies depending
on the maximum record length installed in the SL1400, the number of channels whose
display is turned ON, and the specified sample rate.
*
Internal clock and external clock (time base selection)
Under the initial setting, the sampling timing of waveform data is controlled by the clock signal
generated from the time base circuit within the SL1400.
The sampling timing can also be controlled by a clock signal applied externally. External clock
signals are input through the external clock input terminal on the left panel facing the SL1400.
This external clock input is useful for observing a signal whose period varies or for observing
waveforms by synchronizing to the clock signal of the signal being measured.
T/div
T/div is 1/10th the record time or the time per one grid square (1 div).
1 div = 500
µ
s
10 div
1 div = 1 ms
Record time 5 ms
10 div
Record time 10 ms
Sample Rate
The sample rate is the number of times the measured waveform is sampled (in unit of S/
s). The sample rate is set according to the measurement purpose or the speed of
variation.
The maximum sample rate varies depending on the module. The SL1400 can display
waveforms correctly up to one-half the frequency of the sample rate as defined by the
Nyquist sampling theorem.*
*
If the sample rate is comparatively low with respect to the input signal frequency, the
harmonics contained in the signal are lost. In this case, some of the harmonics will appear at
low frequencies due to the effects described by the Nyquist sampling theorem. This
phenomenon is called aliasing. You can prevent aliasing by acquiring waveforms with the
acquisition mode set to envelope.
Aliasing signal
Input signal
Sampling point