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You can adjust the HORIZONTAL POSITION control to view waveform data before the trigger, after
the trigger, or some of each. When you change the horizontal position of a waveform, you are actually
changing the time between the trigger position and the screen center.
For example, if you want to find out the cause of a glitch in your test circuit, you should trigger on
the glitch and make the pretrigger period long enough to capture data before the glitch. Then you
can analyze the pretrigger data and perhaps find the cause. You are allowed to change the
horizontal scale of all the waveforms by turning the SEC/DIV knob. For example, you may want to
see just one cycle of a waveform to measure the overshoot on its rising edge. The oscilloscope
shows the horizontal scale as time per division in the scale readout. Since all active waveforms
use the same time base, the oscilloscope only displays one value for all the active channels.
4.5 Waveform Measurement
The oscilloscope displays graphs of voltage versus time and can help to measure the displayed
waveform. There are several ways to take measurements, using the graticule, the cursors or
performing an automatic measurement.
Graticule: This method allows you to make a quick, visual estimate and take a simple
measurement through the graticule divisions and the scale factor.
For example, you can take simple measurements by counting the major and minor graticule
divisions involved and multiplying by the scale factor. If you counted 6 major vertical graticule
divisions between the minimum and maximum values of a waveform and knew you had a scale
factor of 50mV/division, you could easily calculate your peak-to-peak voltage as follows:
Cursor: This method allows you to take measurements by moving the cursors. Cursors always
appear in pairs and the displayed readouts are just their measured values. There are two kinds of
cursors: Amplitude Cursor and Time Cursor. The amplitude cursor appear as a horizontal broken
line, measuring the vertical parameters. The time cursor appear as a vertical broken line, measuring
the horizontal parameters.
When using cursors, please make sure to set the Source to the waveform that you want to measure
on the screen. To use cursors, push the CURSOR button.
DS2002A Series Digital Storage Oscilloscope User Manual
6 divisions x 50mV/division = 300mV.
Main Feature Description
12
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