Tektronix TDS5054, User Manual

Page: 97 / 361

Acquiring Waveforms
3- 30
TDS5000 Series User Manual
Before a signal can be acquired, it must pass through the input channel where it
is scaled and digitized. Each channel has a dedicated input amplifier and digitizer
as shown in Figure 3--9; each channel can produce a stream of digital data from
which the oscilloscope extracts waveform records. Refer to
Signal Connection
and Conditioning on page 3--4 for further description of scaling, positioning,
and DC offsetting of channels.
Digitizer
CH 1
Digitizer
CH 2
Digitizer
CH 3
Digitizer CH 4
Figure 3- 9: Digitizer configuration
Acquisition is the process of sampling an analog signal, converting it into digital
data, and assembling it into a waveform record, which is then stored in acquisi-
tion memory. Sampling, then, is the process that provides a waveform record per
trigger event (see Figure 3--11 on page 3--32). The signal parts within the vertical
range of the amplifier are digitized. See Figure 3--10.
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 3- 10: Digital acquisition — sampling and digitizing
Acquisition Hardware
Sampling Process