User manual

Understanding Oscilloscope F unctions
Rising edge Falling edge
Trigger level can b e adjusted
vertically
Trigger can be rising or falling
Acquiring Signals
When you acquire a signal, the oscilloscope converts it into a digital form a nd
displays a w aveform. The acquisition mode d efines how the signal is digitized,
and the time base setting affects the time span a nd level of detail in the acquisition.
Acquisition Modes
There are three acquisition modes: Sample, Peak Detect, and Average.
Sample. In this acquisition m ode, the oscilloscope samples the signal in evenly
spaced intervals to construct the waveform. This mode accurately represents
signals most of the time.
However, this mode does not acquire rapid variations in the signal that may occur
between samples. This can result in aliasing, and may cause narrow pulses to be
misse
d. In these cases, you should use t he Peak Detect mode to acquire data.
(See page 23, Time Domain Aliasing.)
Peak Detect. In this acquisition m ode, the oscilloscope finds the highest and
lowest values of the input signal over each sample interval and uses these v alues
to display the waveform. In this way, the oscilloscope can acquire and display
nar
row pulses, which may have othe r wise been missed in Sample mode. Noise
will appear to be higher in this mode.
Average. In this acquisition mode, the oscilloscope acquires several waveforms,
averages them, and displays the resulting waveform. You can use this mode to
reduce random noise.
T
ime Base
The oscilloscope digitizes waveforms by acquiring the value of an input signal
at discrete points. The time base allows you to control how often the values are
digitized.
To adjust the time base to a horizontal scale that suits your purpose, use the
Horizontal Scale knob.
22 TBS1000 Series Oscilloscopes User Manual