Kodak DirectView CR 825 Theory Manual page 95

THEORY GUIDE
10DEC05
TG4825-1
Page
MICROCOMPUTED
95 of 120
RADIOGRAPHY
DIGITIZER
CONTROLLER -
DIGITIZER - A3
GALVO - A4
PHOTOMULTIPLIER
TUBE/ DATA
AQUISITION
SYSTEM (PMT/DAS)
- A5
BOARD
Obtains the image data from the PMT/DAS BOARD A5 and sets up
timing and control to the PMT/DAS BOARD A5 and GALVO BOARD
A4. The DIGITIZER BOARD A3:
• synchronizes the start and horizontal motion of the GALVO fast
scan and the PMT/DAS A/D CONVERTERS that obtain the data
• receives image data a pixel at a time from the PMT/DAS BOARD
A5 and stores the data in a FIFO BUFFER until a line is
completed. One pixel is made of 32-bit segments.
• starts DMA transfer of the image data from the FIFO BUFFER to
the MCPU BOARD A2 when each line is completed
Provides drive and feedback signals to control the position of the
GALVO MIRROR that provides the deflection of the laser beam onto
the SCREEN during the fast scan operation.
• The DIGITIZER BOARD A3 sends data to the GALVO BOARD
A4, then sends timing signals used by the GALVO BOARD to
command the GALVO to move the MIRROR through a full line
cycle.
• At the end of the cycle, the GALVO BOARD A4 sends a signal to
the DIGITIZER BOARD A3 to indicate that the line is completed.
• A closed loop SERVO CIRCUIT in the GALVO BOARD A4 uses
the POSITION SENSORS in the GALVO to keep the speed of the
MIRROR smooth and in the position necessary for the
maintenance of image quality.
The GALVO BOARD A4 also provides timing and control of the
LASER DIODE DRIVER BOARD A17.
Amplifies, adds, and filters the data from the 2 PMTs, then changes
the analog data to digital data. The PMT/DAS BOARD A5 also
supplies power to the 2 PMTs.
Description
Logic and Control