OWON HDS1021M - Manual (Page 28)

OWON HDS1021M Handheld DSO & DMM 6-Using the scope
they are gathered in the following three different modes, such as sampling, peak value detection
and averaging values.
Sampling: The oscilloscope takes samples from the signal at a equal time interval to reconstruct
the waveform in this mode, by which the analog signal can be expressed correctly in most cases,
yet, the rapid changes can not be collected between two sampling time intervals, causing the
confusion and loss the narrow pulse in the signal probably.
Peak value detection: The oscilloscope takes samples from the maximum and minimum of
signals in each sampling interval and shows the waveform with the sampled data in this mode,
thus, by which the oscilloscope may collect the possibly lost narrow pulse in the sampling mode
but the noise is obvious.
Averaging values: the oscilloscope collects several waveforms and average over them, and
displays the averaged waveform in this mode, by which the random noise can be reduced.
Duration time: When a new waveform is displayed, the previous waveform shown on the screen
does not disappear immediately only to be displayed for a period of time, that is, the duration time,
by setting which, the waveform can be displayed more continuously and thus a display similar to
that shown by the analog oscilloscope can be achieved.
Roll scan mode: The oscilloscope updates the waveform sampling points by scrolling display
through a screen from left to right in this mode, which is only applicable to the primary time base
setting of above 50ms.
6.15 Selecting AC-coupling
After a reset, the Oscilloscope is dc-coupled so that ac and dc voltages appear on the screen, Use
ac-coupling when you wish to observe a small ac signal that rides on a dc signal. To select
ac-coupling, do the following:
1. Press MENU key than the function menu appears at the right side of the screen.
2. Press MENU ▲ or MENU ▼ key to select the CH SETUP. Four items selectable are
visible at the bottom of the screen.
3. Press the F1 key and jump to AC. The bottom left side of the screen displays the
ac-coupling icon.
Now, you can see a screen that looks like the following figure 15.
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