channels ever go negative. The A/D converter converts the analog signal into 16 bit parallel data
for processing by a Digital Signal Processor.
The ADC board uses a Motorola 56000 Digital Signal processor to generate all the control
signals necessary for the detector array assembly. This processor is used to generate pseudo
channels when a low resolution (4mm) array is used. A pseudo channel is generated between
every low resolution channel before the data is sent to the computer. This makes the low
resolution array data the same as the high resolution array data. The same software can now be
used with all systems. This processor also provides a high speed serial data link to the computer.
Note: Jumper JP5, on the ADC board, is used to select between high and low resolution. When
the jumper is in the board is configured for high resolution, when the jumper is out the
board is configured for low resolution.
Power
The ADC board receives +/-15V and + 7V from the C-arm Interface board. The +/-15V is
passed through this board to the Integrator/multiplexor board. It is also reduced to +/-12V by
series regulators to power op-amplifiers and analog switches located on this board. The +/-15V
also generate +/-5V to power the analog-to-digital converter circuit. The +7V is reduced to +5V
to power the digital section of this board. The +5V is also passed on to the
Integrator/Multiplexor board.
Interface Connections
Figure 2-17 shows the interconnections between the Analog/Digital Converter board and the
Integrator/Multiplexor board. Table 2-23 describes the interface signals and identifies the
interconnection connector and pin assignments.
C-ARM INTERFACE
BOARD
Figure 2-17. C-Arm Interface Board/Analog/Digital Converter Board
Section 2 - Functional Description
STD+, STD-
STCLK+, STCLK-
STFRM+, STFRM-
SRD+, SRD-
SRCLK+, SRCLK-
SRFRM+, SRFRM-
SYSRST_DAS+, SYSRST_DAS-
INTEGRATE+, INTEGRATE-
XR_ZEROX_DAS+, XR_ZEROX_DAS-
+15V
15V_RET
-15V
+7V
Interconnection Diagram
ANALOG/DIGITAL
CONVERTOR
BOARD
2-31
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