Tektronix Acquisition Hardware, Sampling Process

Acquiring Waveforms
3-40 CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments 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--8; each channel can produce a stream of digital data from
which waveform records can be extracted. See Signal Connection and Condi-
tioning on page 3--8 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- 8: Digitizer configuration
Acquisition is the process of sampling the analog input signal of an input
channel, converting it into digital data, and assembling it into a waveform
record, which is then stored in acquisition memory. Sampling, then, is the
process that provides a waveform record per trigger event (see Figure 3--10 on
page 3--42). The signal parts within the vertical range of the amplifier are
digitized. See Figure 3--9.
Input signal Sampled points Digital values
+5.0 V
-- 5 . 0 V
+5.0 V
-- 5 . 0 V
0V 0V 0V 0V
Figure 3- 9: Digital acquisition — sampling and digitizing
Acquisition Hardware
Sampling Process