GE FC091194, Руководство по обслуживанию

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GE M
EDICAL
S
YSTEMS
D
IRECTION
FC091194, R
EVISION
02 V
IVID
7 / V
IVID
7 PRO S
ERVICE
M
ANUAL
Chapter 5 - Components and Functions (Theory) 5 - 5
5-3-3 Phased and Linear Array Front End (cont’d)
• The ultrasound transmit bursts are generated on the TX board, initiated by the transmit trigger pulse
(TXTRIG_L). The transmit trigger starts the Transmit Pulse Generators (TPG) on the TX board,
each generating 16 transmit pulses with different delays. The transmit pulses are then routed to
separate transmit “amplifiers” fed with voltage HV1 and HV2 witch are controlled by the Acoustic
Power control software.
• The transmit pulses are routed over an Xducer Bus Board (XDBUS) located on the front side of the
Front End boards, to the Relay board, where they are fed to the selected (one out of three) phased/
linear array probe.
• The reflected signal from body structures and blood cells are routed from the probe, via the Relay
board over the Xducer Bus to the RX (receiver) board, where preamplification (20dB) and Analog
Time Gain Compensation (ATGC) (-10 - +30 dB) is performed. Gain is determined by an analog
signal (ATGC) generated by the FEC board.
On the very input of the RX board are transmit/receive (T/R) switches to prevent the transmitters
from destroying the receivers. Prior to preamplification the signals from the different channels were
also fed through relays. This is for having the possibility to route echoes from annular array probes
into the receiver, in addition to injecting a test signal, TSIG.
• The output channels from the RX board are fed to two Beamformer-64 boards. Each Beamformer
board performs A/D conversion of 64 channels.
• The Front End Controller board controls all Front End boards. The board loads all parameters to the
TX and Beamformer RAMs, it reads the probe identification, selects probe connector on Relay
board and controls the high voltage multiplexer in linear probes. In addition the board generates the
transmit trigger pulse for TX, a receive synchronization pulse (SYNC_L) used by Beamformers and
RF & Tissue Processor, a differential ATGC voltage used by RX and control signals for the High
Voltage Power Supply (HV POWER). The Front End Controller board also generates the global 40
MHz system clocks and reset pulse (SRES).
• The output from the Beamadders at BF#2 is fed to the RF and Tissue Processor Board (RFT).
5-3-4 Transmitter Power Supply
The transmitters on the TX board are fed with high voltage from the TX supply. This module consists of
three linear power supplies; one providing a symmetrical output voltage ranging from 0 to +/- 80 V
(HV1), the other providing a voltage ranging from 0 to +/- 40 V (HV2) and the third outp/- 80 V
for the multiplexers in the linear probes. HV1 and HV2 are programmable through a serial interface from
the FEC board.
5-3-5 Mid Processors
The Vivid 7 / Vivid 7 PRO Front End and visualization system are interconnected through digital signal
processing modules, called the Mid Processors. These processors performs the adequate signal
conditioning for the different data types; Tissue, Doppler and Flow. The current Mid Processors are the
RF & Tissue Processor board (RFT), the Spectrum Doppler Processor board (SDP).
5-3-5-1 Pipelink bus
• The Mid Processors are interconnected through a data bus system called the Pipelink. This is a
unidirectional bus transporting data from the pipelink dispatcher (RF & Tissue Processor) through
the accessed processor to the destination, the Image Port. The Image Port will then map the data
into the Image Memory.
• Data leaving the RF & Tissue Processor have a tag indicating what type of data that is transported;
e.g. tissue, Doppler, 2D Flow. Each of the remaining mid processors decode this tag and when it
matches their own address, the data is processed. Data that doesn’t have a matching tag, is passed
on to the next processor.
• In 2D, data is typically transferred in vector blocks from the RFT board. In spectrum Doppler and
Color Flow, data from one range gate is transferred.