S6 Portable Digital Color Doppler Ultrasound System
Service Manual
Color Flow Mode (CFM)
CFM (Color Flow Mode) is also called CDI (Color Doppler Mode) some-
times. CFM combines 2D grayscale imaging with color imaging. The 2D
imaging gives information on tissues; the color imaging, which uses the
Doppler principle, gives information on blood flow. The output is the color
image overlaid with the 2D grayscale image.
Power Doppler (DPI)
The color image in Power Doppler Imaging (DPI) is in principle different
from that in CFM. DPI analyzes amplitude shift, while CFM analyzes fre-
quency shift. The color image is overlaid onto the 2D grayscale image
which gives information on tissues. DPI is capable of detecting low speed
blood flow.
A high pass filter (wall filter) is used to remove the signals from stationary
or slowly moving structures. Tissue motion is discriminated from blood
flow by assuming that blood is moving faster than the surrounding tissue,
although additional parameters may also be used to enhance the discrimi-
nation. The power in the remaining signal after wall filtering is then aver-
aged over time (persistence) to present a steady state image of blood flow
distribution.
4.5 Functional Boards/Units of the S6 System
Besides the probes, the S6 system consists of the following critical func-
tional boards/units.
6
MPC board: Also called probe board. Two probes can be connected
at the same time and one of them active (scanning).
6
DBTR board: It has an emitting pulse synthesizer and a receiving
signal preamplifier/TGC. The DBTR sends electronic signals to drive
the probes and pre-amplifies the echoes.
6
DBF board: It converts analog signals to digital signals and sends
the signals for digital beam forming (DBF). DBF board also has scan
controller, front end controller, demodulation unit and USB ports.
6
DBHV board: It provides the high voltages for the pulse generator
and the low voltages for other system units. The ECG and 4D motor
units are also on this board.
6
PC Motherboard: It is the core data processing unit of the S6 system.
6
Power supply: ATX SMPS power supply. It provides stable power
supply to the whole system (probes, host and LCD monitor).
6
User Keyboard: hard keys, trackball, flip switches and knobs.
P/N: 4720-0034-01A
4-3
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