Tektronix TPS2012B, Руководство пользователя

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Understanding Oscilloscope Functions
Rising edge Falling edge
Trigger level can be adjusted
vertically
Trigger can be rising or falling
Acquiring Signals
When you acquire a signal, the oscilloscope converts it into a digital form and
displays a waveform. The acquisition mode de
fi nes how the signal is digitized,
and the time base setting affects the time span and level of detail in the acquisition.
Acquisition Modes There are three acquisition modes: Sample, Peak Detect, and Average.
Sample.
In this acquisition mode, 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
missed. (See page 31,
Time Domain Aliasing .) In these cases, you should use
the Peak Detect Mode to acquire data.
Peak Detect. In this acquisition mode, the oscilloscope fi nds the highest and
lowest values of the input signal over each sample interval and uses these values
to display the waveform. In this way, the oscilloscope can acquire and display
narrow pulses, which may have otherwise 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.
Time 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
Scale knob.
30 TPS2000B Series Digital Oscilloscope User Manual