Tektronix TPS2012B, User Manual

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Understanding Oscilloscope Functions
Scaling and Positioning Waveforms
You can change the display of waveforms by adjusting the scale and position.
When you change the scale, the waveform display will increase or decrease in size.
When you change the position, the waveform will move up, down, right, or left.
The channel indicator (located on the left of the graticule) identi fi es each
waveform on the display. The indicator points to the ground reference level of
the waveform record.
You can view the display area and readouts. (See page 16, Display Area .)
Vertical Scale and Position You can change the vertical position of waveforms by moving them up or down in
the display. To compare data, you can align a waveform above another or you can
align waveforms on top of each other.
You can change the vertical scale of a waveform. The waveform display will
contract or expand relative to the ground reference level.
For oscilloscope-speci fi c descriptions, refer to the Operating Basics chapter. (See
page 21, Vertical Controls .) Refer also to the Reference chapter. (See page 120,
Vertical Controls .)
Horizontal Scale and
Position; Pretrigger
Information
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
and 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 fi nd the cause of a glitch in your test circuit, you
might trigger on the glitch and make the pretrigger period large enough to capture
data before the glitch. You can then analyze the pretrigger data and perhaps
fi nd
the cause of the glitch.
You change the horizontal scale of all the waveforms by turning the Scale knob.
For example, you might 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, except when you use Window
Zone. Refer to
Window Zone for information on how to use the window function.
(See page 105, Window Zone .)
For oscilloscope-speci fi c descriptions, refer to the Operating Basics chapter.
(See page 22, Position .) Refer also to the Reference chapter. (See page 104,
Horizontal .)
Time Domain Aliasing. Aliasing occurs when the oscilloscope does not sample the
signal fast enough to construct an accurate waveform record. When this happens,
TPS2000B Series Digital Oscilloscope User Manual 31