GE H48651KR, Руководство по обслуживанию

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GE V
OLUSON
i / V
OLUSON
e
D
IRECTION
KTI106052, R
EVISION
10 S
ERVICE
M
ANUAL
5-10 Section 5-2 - General Information
5-2-4-1-1 Special B Mode Techniques
a.)
HI
(Coded Harmonic Imaging)
In one method of HI the RX-Frequency is doubled, so that the radial resolution is increased
due to the higher RX-Frequency.
The second method of HI is pulse-inversion: 2 TX-Beams are shot to the same Tissue-location,
one with positive, one with negative polarity. The subtraction of both shots (Subtraction Filter)
brings to bear the nonlinear-echo-reflection-properties of the tissue, which is very useful with
extremely difficult-to-image patients.
5-2-4-2 M-Mode
1.) RBI
see: 5-2-4-1 B-Mode
a.) DMA section
B-mode-Data from RBI is written via SP0 into SDRAM Fifo Buffer memory. DMA Controller 1
transfers the data into PC main memory where scan conversion is performed per software,
i.e. the sweep image is generated (scaling and interpolation between lines).
CineMode: CineMode-Memory is the PC main memory.
2.) RBF
see: 5-2-4-1 B-Mode
5-2-4-3 D-Mode (Pulsed Wave Doppler)
1.) RBI
- PRF-generator; see: 5-2-4-1 B-Mode
- After DC-cancelling the signal is mixed with RX-Frequency and brought to LF-Spectrum,
where the LowPassFilter cuts HF.
Mixer and Magnitude-Calculator arrange Complex Demodulation.
a.) DMA section
D-mode-Data from RBI is written via SP1 into SDRAM Fifo Buffer memory. DMA Controller 1
transfers the data into PC main memory where scan conversion is performed per software,
i.e. the sweep image is generated (scaling and interpolation between lines).
CineMode: CineMode-Memory is the PC main memory.
2.) RBF
see: 5-2-4-1 B-Mode