UnderstandingOscilloscope Functions
TDS1000/2000-Series Digital Oscilloscope User Manual 19
Horizontal Scale and Position; Pretrigger Information
You can adjust the HORIZONTAL POSITI ONc ontrol to view
waveform data beforethe trigger, after the trigger,or some of each.
When you change the horizontalposition of a waveform, you are
actually changing the time between the triggerand the center of the
display. (This appears to move the waveform to the right or left on
the display.)
For example, if you want to findthe cause of a glitch in your test
circuit, you might trigger on the glitchand make the pretrigger
period large enough to capture data before the glitch. You can then
analyze the pretrigger dataand perhaps find the cause of the glitch.
You change the horizontal scale of all the waveforms by turning the
SEC/DIV knob. For example, you might want to see just one cycle of
a waveform to measure the overshoot on its rising e dge.
The oscilloscope shows the horizontalscale as time per division in
the scale readout. Since all acti ve waveformsuse the sam e time base,
the oscilloscope onlydisplays one value for all the active channels,
except when you use Window Zone. For information on how to use
the window function, refer to page 92.
For oscilloscope-specific descriptions,refer to page 35 in the
Operating Basicscha pter and page 90 in the Reference chapter.