The only difference between the MDO34 and MDO32 block diagram is the AFE board.
Figure 2: MDO32 AFE board
Power supply
The Power Supply board converts AC line voltage to +12 V to power for all internal circuits.
I/O board
The I/O board contains USB ports, an Ethernet port (LAN), a HDMI port, an AUX OUT BNC connector, and the AFG generator output
connector.
Main board and front-end board
The Main and Analog boards contain the following functions:
Acquisition system
The Acquisition system begins with the analog signal path and ends with a digitized signal in memory. The
signal enters a channel input, and then passes through an attenuator and preamplifier. The analog signal
from each preamplifier goes through a digitizer, and then into acquisition memory. The analog signal from
each preamplifier is also distributed to a trigger circuit. The digital channels pass through the front of the
instrument to the Main board.
Front-end
All of the analog inputs are routed to the Front-end board. The analog channels are amplified and
attenuated through the front-end circuitry, and are output to the Main board. The front-end board has a
controller that is used as an I/O controller for the front-end board.
Mezzanine
The Mezzanine board converts the +12 V power to some of the other voltages used for the analog and
digital circuitry throughout the system.
Front panel and display
The Front Panel board contains digital logic that reads the front-panel buttons and controls and sends this information to the processor
system on the Main board. The Front Panel board also generates the probe compensation output signal and provides USB ports on the
front panel. The front panel routes the front-end signals from the probe directly to the front-end board.
Theory of operation
3 Series MDO Mixed Domain Oscilloscope Service Manual
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