Theory of Operation
WFM700 Series Waveform Monitors Service Manual 1-5
The Main Interface board provides signal paths and communication paths
between all modules.
HPCI Bus and Serial Control Bus are used for control and data transfer. Both
go to all slots. The PCI Bus is typically used for modules requiring
high-speed performance and communication between modules without the
use of the CPU board. The Serial Control Bus is used for modules requiring
less control and speed.
HThe Timing Bus is used to distribute the TRS signal to the Input Modules
and the RTD board.
HThe Audio Bus routes the digital audio signal (extracted from the video
serial input) to the module slots for use by future modules.
HThe Video Bus routes the parallel video signal (with clock and sync signals)
to the RTD slot from the two Input slots.
The Main Interface board provides power distribution, contains thermal sensors,
and contains the Environmental Controller (EC). The EC monitors the front
panel ON/STBY switch to control the main power supply (in the Power Supply
module) and monitors all low voltage power sensors for inaccurate voltage
The VGA Controller routes the video signal to both the LCD and the EXT VGA
output. This output can be used to drive an external monitor to produce the same
display as seen on the LCD.
HEXT VGA. Provides an exact copy of the LCD screen to drive an external
Main Interface Board