Tektronix, Inc. P6240, User Manual

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TLS 216 User Manual
2–19
Acquisition
Acquisition is the process of sampling the analog input signal, converting it into
digital data, and assembling it into a waveform record. The TLS 216 Logic
Scope creates a digital representation of the input signal by sampling the voltage
level of the signal at regular time intervals. (See Figure 2-4.)
Input Signal Sampled Points Digital Values
+5.0 V
–5.0 V
+5.0 V
–5.0 V
0 V 0 V 0 V 0 V
Figure 2-4: Acquisition: Input Analog Signal, Sample, and Digitize
The sampled points are stored in memory along with corresponding timing
information. You can use this digital representation of the signal for display,
measurements, or further processing.
You specify how the logic scope acquires data points and assembles them into a
waveform record.
Sampling and Digitizing
The trigger point marks time zero in a waveform record. All record points before
the trigger event make up the pretrigger portion of the waveform record. Every
record point after the trigger event is part of the posttrigger portion. All timing
measurements in the waveform record are made relative to the trigger event.
Each time the logic scope takes a sample, it digitizes it to produce a numeric
representation of the signal.
The logic scope creates a waveform record containing a user-specified number of
data points. Each record point represents a certain voltage level that occurs a
determined amount of time from the trigger event.
The record length determines the number of points that make up the waveform
record. Use the record length in the Horizontal menu. The logic scope provides
record lengths of 500, 1000, and 2000 points.
Record Length