Agilent Technologies InfiniiVision 3000 X- Series, Advanced Training Manual, Page: 112 / 128

112 3000 X-Series Oscilloscopes Advanced Training Guide
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Oscilloscope Block Diagram and Theory of Operation
DSO Block Diagram
Figure 84 shows the block diagram of one channel of acquisition of a
typical digital storage oscilloscope (DSO). The yellow- shaded blocks
represent system components unique to a single channel of acquisition,
such as Channel- 1 or Channel- 2. The blue- shaded blocks represent system
components that are common among all channels of acquisition, such as
the scope’s common timebase and CPU system.
ADC Block
Shown near the middle of this block diagram is the analog- to- digital
convertor (ADC). The ADC block is the core/central component of all
DSOs. The function of this block is to convert the analog input into a
series of digital words. Most of today’s DSOs utilize 8- bit ADCs which will
provide 256 unique digital output levels/codes. These digital binary codes
are stored in the scope’s acquisition memory, which will be discussed
later. If the analog input level to the ADC is equal to or less than –V, then
the output of the ADC will be 00000000 (0 decimal). If the analog input
level to the ADC is equal to or greater than +V, then the output of the
Figure 84 DSO block diagram
Attenuator
Amplifier
8-bit
ADC
Display
DSP
Scope Display
Acquistion
Memory
CPU
System
Timebase
System
Trigger
Logic
Trigger
Coupling
Trig Comp
Input
BNC
DC
Offset
DC Trigger
Level