GE HEALTHCARE
DIRECTION FC091194, REVISION 11 VIVID 7 SERVICE MANUAL
5 - 62 Section 5-3 - a Front-End Processor (FEP)
5-3-21-4 Data Buffer
After RF filtering, the data is written into different sliding ring buffers, dedicated to the different types of
data. While data is written into the buffers sample by sample in vectors, multiple samples from the same
range (depth) can be read out.
Both input addressing (start and length) and output addressing (through output events) are controlled
by the RFI board itself.
5-3-21-5 Tissue Processing
A number of different tissue processes are performed on this board:
1.) First the signal amplitude is obtained by detection.
2.) Then the data is compressed to attenuate the strong signals and amplify the low level echoes.
3.) After compression, Zone Stitching is performed. Zone Stitching is used to combine the (transmit)
focal zones from different vectors into one vector by weighting the zone transitions, and does only
apply to phased/linear array probes where multiple vectors can be collected in the same direction.
For M-Mode, peak detection and edge enhancement is implemented.
4.) Finally an offset can be added to the signal and clipping is performed.
5-3-21-6 Color Flow Processing
No Color Flow processing is performed here, except for the RF demodulation previously mentioned.
The data used for Color Flow is tagged with the appropriate headers and tails and sent to the Back-End
Processor (BEP).
5-3-21-7 Doppler Data
Doppler Data is high pass filtered, to remove strong low frequencies returned from wall motion, valves
and leaflets, on RFI and then sent to the BEP and to Audio Circuitry.
5-3-21-8 System Temperature Surveillance
The RFI board monitors the temperature in the airflow at the air intake and in the airflow at the air outlet.
• If the temperature inside the system (at the air outlet) increases to 60
o
C, a “High System
Temperature” error will be displayed on the screen.
• If the temperature increase to 65
o
C, the system will start an automatic shutdown.
The temperature will normally be recorded at startup, and then repeated every hour. This frequency will
increase if the temperature exceeds the limit.
The temperature measurements make it possible to monitor the environmental conditions
(temperatures) for the scanner and prevent overheating.
The temperature measurements are available in a temperature log available via the Service Platform.
It is also available at D:\log\logfile-temp.txt.
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