Acuson Sequoia System Architecture User manual
MODULE 5
SYSTEM ARCHITECTURE
Overview 5-4
Objective 5-4
Purpose 5-4
Instructions 5-4
System Architecture 5-5
System Chassis 5-5
Basic System Architecture 5-6
Coherent Imageformer 5-7
Coherent Imageformer 5-7
Multiple Beamformation 5-7
Coherent Imageformer PCBs 5-7
Theory of Operation 5-8
Transmission 5-8
Reception 5-9
Transmitter Board 5-11
TX3 5-11
Function 5-11
Troubleshooting Hints 5-11
Multiplexer Board 5-12
MX2/3 5-12
Function 5-12
Troubleshooting Hints 5-12
Receiver Board 5-13
RX 5-13
Function 5-13
Troubleshooting Hints 5-13
RI Board 5-14
Beamformer Board 5-15
BF3 5-15
Function 5-15
Troubleshooting Hints 5-15
Controller Board 5-16
CN2/3 5-16
Function 5-16
Troubleshooting Hints 5-16
DIMAQ Integrated Ultrasound Workstation 5-17
The DIMAQ Workstation PCBs 5-17
Module 5 - System Architecture Acuson Confidential
Theory of Operation 5-18
Acquisition and Preprocessing 5-18
Reconstruction 5-18
Video Conversions 5-18
DIMAQ Workstation Subsystem Control 5-18
System Supervisory Processor 5-18
Scan Formats 5-19
User Interface 5-19
Color and Spectral Doppler Board 5-22
CSD1/2 5-22
Function 5-22
Spectral and Audio Processing 5-22
Color Doppler Processing 5-22
Troubleshooting Hints 5-22
BDM Board 5-23
BDM1/2 5-23
Function 5-23
SMM Processor 5-23
Reconstruction and Display Processor Board 5-24
RDP2/5 5-24
Function 5-24
SSP 5-24
Troubleshooting Hints 5-24
Input/Output Video Board 5-25
IOV1/2 5-25
Function 5-25
Troubleshooting Hints 5-25
Input/ Output Expansion Board 5-26
IOE3 5-26
Function 5-26
Troubleshooting Hints 5-26
Peripheral Interface Controller Board 5-27
PIC1/2 5-27
Function 5-27
Troubleshooting Hints 5-27
Physio Interface Module 5-28
FIZ 5-28
Function 5-28
Troubleshooting Hints 5-28
Front Panel Processor Board 5-29
FPP 5-29
Function 5-29
Troubleshooting Hints 5-29
2-D/ M-Mode Signal Flow 5-30
Transmission 5-30
Module 5-2 Sequoia Service Training Manual P/N 59155 Rev. 1
Acuson Confidential
Reception 5-30
Reconstruction and Display 5-30
Solo™ Spectral Doppler Signal Flow 5-33
Doppler Theory 5-33
Pulse Wave Doppler 5-33
Nyquist Limit 5-33
High PRF 5-33
Continuous Wave Doppler 5-33
Solo™ Spectral Doppler 5-34
Display 5-34
Audio 5-34
Color Doppler Signal Flow 5-35
Color Doppler 5-35
SST™ Color Doppler 5-35
ECG/Physio Signal Flow 5-37
DIMAQ System Store and Review 5-38
Acquisition 5-38
Review 5-38
VCR Playback 5-40
Acquisition 5-40
Playback 5-40
Worksheet: System Architecture 5-41
REVISION HISTORY
QRC P/N-REVISION INITIATOR APPROVAL DATE CHANGE
S. Williams July 1999 Incorporate reviewer comments
A3210 59155 Rev. 1 J. Madarasz S. Williams Dec. 2000 Initial Release
P/N 59155 Rev. 1 Sequoia Service Training Manual Module 5- 3
Module 5 - System Architecture Acuson Confidential
OVERVIEW
OBJECTIVE To explain the signal paths for different the Sequoia system
ultrasound modalities and board functions, in order for Customer
Engineers, International Distributors and BioMed Engineers to
troubleshoot a Sequoia sy stem problem.
PURPOSE Troubleshooting a Sequoia system at a customer site can be a
demanding task. Most of the time, isolating the cause of a failure is
an easy task using the state-of-the-art service diagnostic software.
However, occasionally the failure symptom must be related to th e
function of a specific board. Following the signal path for the
modality can also be a useful tool in such a situa tion.
INSTRUCTIONS 1 Listen to the presentation.
2 Read the module.
3 Answer the questions in the worksheet provided at the end of the
module.
Module 5-4 Sequoia Service Training Manual P/N 59155 Rev. 1
Acuson Confidential System Architecture
SYSTEM ARCHITECTURE
SYSTEM CHASSIS The Sequoia system consists of a card cage with a capacity for up to
15 printed circuit boards (PCB), plus the backplane. Access to the
PCBs is available by removing the right side cover and removing
the shielding cover from the card cage.
CAUTION! The Sequoia system contains numerous devices sensitive to
electrostatic discharge (ESD). Failure to observe strict ESD prevention
procedures may damage components. Access to internal assemblies is
restricted to Acuson trained service personnel only.
T ransducers are plugged directly into the system via the MX board.
Depending on the system configuration, up to three 128-element
transducers or one 256-element transducer and two 128-element
transducers may be connected at one time. The right transducer
connector only supports a 256-element transducer on the Sequoia
512 system.
The DC power is supplied to the chassis from a single power supply
located at the rear of the chassis, behind the service access cover.
Power connections to the printed circuit boards are made via the
backplane of the card cage. See the Following Power Distribution
module for more detail.
WARNING!
Voltages present within the Sequoia system are capable of causing
injury or death. Access to internal assemblies is restricted to Acuson
trained service personnel.
P/N 59155 Rev. 1 Sequoia Service Training Manual Module 5- 5
Module 5 - System Architecture Acuson Confidential
BASIC SYSTEM
A
RCHITECTURE
Sequoia system technology represents the most fundamental and
far-reaching advance in ultrasound technology since the advent of
Computed Sonography in 1983. It incorporates four foundation
technologies that produce dramatic image quality, performance,
and functionality improvements in all mode s of operation. The
system architecture can be divided into three major subsystems:
• Coherent Imageformer
•DIMAQ workstation
• Power Subsystem
Figure 5-1 illustrates the basic Sequoia system architecture.
Xdcr
Audio FRQ
Spectral Beamformer
Digital Receive
Xmt/Rcv
Switching
Imageformer Subsystem
Beamformer
Transmit
Beamformer
Control
User
PW
CW
Color
2-D
M-mode
Monitor
Interface
System
Supervision
Memory
&
Scan
Conversion
AEGIS system &
Ethernet
DIMAQ Integrated Workstation
OEMs
Peripheral
Interface
Video
Conversion
PPS
Power Subsystem
Main Power Supply
Figure 5-1 Basic System Architecture of Sequoia System
Module 5-6 Sequoia Service Training Manual P/N 59155 Rev. 1
Acuson Confidential Coherent Imageformer
COHERENT IMAGEFORMER
COHERENT
IMAGEFORMER
MULTIPLE
EAMFORMATION
B
The Coherent Imageformer subsystem performs three primary
functions. These are:
• Transmission of focused ultrasound energy
• Receive and process of back scattered ultrasound energy
• Control of transmit and receive parameters to sweep the
ultrasound beams through the field of view
The Coherent Imageformer performs these functions by setting the
phase and amplitude parameters for each transmit/r eceive element
in the transducer. Sophisticated computer control of these
parameters provides extensive flexibility in controlling the
transmitted ultrasound beam and processing the back-scattered
energy picked up by each transducer element.
The Multiple Beamformer is a new beamformer architecture that
utilizes up to 512 digital processing channels. This unique
architecture:
• Processes phase and amplitude
• Acquires multiple beams simultaneously to capture
information
• Acquires multiple beams in the same amount of time that a
single beamformer acquires a single beam
COHERENT IMAGEFORMER PCBS
The high-speed data acquisition generated by multiple
beamformers translates directly into significantly higher frame
rates, higher spatial resolution and increased sensitivity in 2-D and
Color Doppler imaging modes.
Phase information is utilized by the Coherent Imageformer to
acquire additional information that cannot be done without the use
of phase.
Five major board types make up the Coherent Imageformer. Each of
these boards performs specific functions in the formation of an
ultrasound image cell.
BOARD NAME ACRONYM
Transmitter Board TX
Multiplexer Board MX
Receiver Board RX
Beamformer Board BF
Controller Board CN
P/N 59155 Rev. 1 Sequoia Service Training Manual Module 5- 7
Module 5 - System Architecture Acuson Confidential
THEORY OF OPERATION
TRANSMISSION All Coherent Imageformer functions are controlled by the
Controller board (CN). Data regarding the type of ultrasound
information to acquire, (e.g., 2-D mode, Color, Pulse Doppler, Depth
of Scan, Power to use, etc.) are passed to the CN board on the
system control bus.
The CN then passes parameter data to the transmitter boards on the
Imageformer bus. In addition, configuration data is also passed to
the Multiplexer (MX) and Receiver (RX) boards.
The Tr ansmitter (TX) boards use this data to determine the pulse
characteristics and time delay requir ed. The digital pulse waveform
is passed to a D/A converter, which creates the analog wave used to
drive a high voltage amplifier. This amplifier output drives the
transducer piezoelectric-crystal element. Two TX boards may be
used to process a total of 512 digital processing channels. The high
voltage pulses from the TX board are passed to the Multiplexer
board (MX).
The MX board switches the transmit pulses to the appropriate
transducer element, based upon the transducer(s) connected and
the scan format used.
Each transducer consists of a number of piezoelectric-crystal
elements. A piezoelectric-crystal element changes spatially when a
voltage is applied across it. On receiving a high-frequency electric
wave, the piezoelectric-crystal element vibrates and creates a highfrequency ultrasound wave.
The ultrasound wave propagates into the tissue of the patient being
scanned. Wherever there is a change in the acoustic impedance,
such as the interface between dissimilar tissues, a portion of the
ultrasound wave is reflected. The magnitude of the reflected wave
is a function of the difference in acoustic impedance between the
tissues.
Module 5-8 Sequoia Service Training Manual P/N 59155 Rev. 1
Acuson Confidential Theory of Operation
RECEPTION Immediately after transmitting the ultrasound wave, the system
begins acquiring echo data. A piezoelectric-crystal element not only
changes geometry when a voltage is applied, it also creates an
electric charge when the geometry of the element is mechanically
changed. The ultrasound echo data returning from the patient
excites the piezoelectric-crystal elements. The crystals output a
small electric signal that is proportional to the amplitude of the
received ultrasoun d waves.
The MX board r outes these i n dividual s ignal s to th e Recei ver bo ard
(RX). The RX board provides initial amplification of the echo data.
The signals are processed for gain and then passed to the
Beamformer board (BF), where apodization occurs. The RX board
also creates the clock signals used to synchronize system
operations.
During spectral Doppler operation, the Doppler data is passed to
the Spectral Doppler Preprocessor located on the RX board. The PW
Doppler data is sampled only at the range gate. CW Doppler data is
acquired from the entire sample line. The Doppler data is then
processed and the quadrature data I&Q derived. The I&Q data are
then digitized and placed on the RX I/Q data path for processing
and display by the DIMAQ workstation.
The Beamformer board (BF) rece ives the back-scatter ed echoes from
each receive channel. By processing echoes from numerous
transducer arrays, the BF defines a series of coherently-focused
image cells.
Two BF boards may be used to process four different ultrasound
beams utilizing a total of 512 digital processing channels.
Figure 5-2 diagrams the Imageformer functions.
P/N 59155 Rev. 1 Sequoia Service Training Manual Module 5- 9
Module 5 - System Architecture Acuson Confidential
Freq
Gain
Block
LVA
Gen
SDP
DIMAQ
Workstation
To
AUX
Amplifier
Connectors
MP
MX
RX
RI
RMX
Control &
Calibration
TMX
MAC
PWG
DAC
ADC
CFB
ADC
BFP
CFB
BF-A BF-B
PPS
ACP
PWG
DAC
BBF
BFP
CN
To
DIMAQ
Workstation
FCP
HV
HV
Output
Amplifier
TX-A
Output
Amplifier
TX-B
Figure 5-2 Imageformer Block Diagram
Module 5-10 Sequoia Service Training Manual P/N 59155 Rev. 1
Acuson Confidential Transmitter Board
TRANSMITTER BOARD
TX3
Part Number TX2 35282
Part Number TX3 39142
Quantity Cardiology: 1, Radiology: 2
Power Supplies +5 VDC, +5.5 VDC, -5.7 VDC,
Signals In TX Apodization, TX Delay
Signals Out TX Signal (1-64)
FUNCTION The Transmitter board (TX) provides the electrical signal used to
drive the piezoelectric elements in the transducer. The TX is
controlled by the Controller board (CN) via the IAB bus.
Apodization and delay parameters are passed to the TX by separate
signal lines.
The programmable wave generator (PWG) ASIC generates a digital
transmit waveform for up to four beams.
±12 VDC; Vxmt
TROUBLESHOOTING
H
INTS
The pulse parameters are specified for each transducer element
based on the ultrasound line being fired. The parameters are
converted to an analog signal, which is used to drive a high voltage
amplifier. The high voltage amplifier uses the output from the
Programmable Power Supply (PPS). The PPS is set by software to a
given voltage based on the ultraso und line being fired. The highvoltage transmit pulses for each transducer element are then passed
to the MX board.
Failures of the TX board are most likely to interrupt a single
transmitter channel only. This is unlikely to be visually perceptible.
If problems are suspected, replace the board to check for image
improvement.
P/N 59155 Rev. 1 Sequoia Service Training Manual Module 5- 11
Module 5 - System Architecture Acuson Confidential
MULTIPLEXER BOARD
MX2/3
Part Number MX2 Cardiology: 39052, Radi ology: 36262
Part Number MX3 Cardiology: 50642; Radi ology: 39132
Quantity One
Power Supplies +5.5 VDC;
Signals In TX Signal (64 or 128 channels), TX Off, Control
data
Signals Out MX Signal (64 or 128 channels)
FUNCTION The Multiplexer board (MX) provides the electrical connection
between the Imageformer and the transducers supported by the
Sequoia system.
The MX board has three functions:
±12 VDC; ±100 V
TROUBLESHOOTING HINTS
• To switch the electrical transmit pulse from a selected
transmitter channel to the appropriate transducer element.
• To switch the appropriate transducer element to the proper
receive channel.
• Provide a signal path for calibration signals generated by a
selected transmitter channel to be monitored by a selected
receive channel.
The MX board is controlled by the Controller board (CN) via the
MX/RX Bus. The CN configures the MX based upon the
transducer(s) connected and selected.
Calibration signals may be passed from the Transmitter board (TX)
to the Receiver board (RX) via the MX board. If a transmit or receive
channel fails diagnostics and replacement of the board does not
correct the problem, it is possible that the MX is not providing the
necessary signal path.
Module 5-12 Sequoia Service Training Manual P/N 59155 Rev. 1
Acuson Confidential Receiver Boa rd
RECEIVER BOARD
RX
Part Number RX2 Cardiology: 39052, Radiology: 32012
Part Number RX4 Cardiology: 51642; Radiology: 51562
Quantity One
Power Supplies +5.5 VDC; -5.7 VDC;
Signals In MX Signal (64, or 128)
Signals Out RX Signal, RX I/Q, Master System Clocks
FUNCTION The Receiver board (RX) operates in two ways, depending upon the
type of ultrasound data being processed. When a 2-D, F-mode or Mmode ultrasound line is being processed, the receive signal from
MX for each channel is acquired and passes through circuitry that
amplifies and preprocesses it. The signal is then passed to the
Beamformer board (BF) for construction of an image cell.
±12 VDC
TROUBLESHOOTING
INTS
H
When PW Doppler or CW Doppler data is being acquired, the data
path is quite different. The Doppler data is amplified and
preprocessed based on range gate position (PW), or acquired over
the entire sample line (CW). The Doppler signals are then shifted
temporally to create a coherent ultrasound image cell.
The temporally shifted Doppler data is summed and passed to the
Color Spectral Doppler board (CSD) for conversion from time
domain to the frequency domain.
The RX board also generates the master clock signals used by the
system to synchronize operations.
The RX board is the point in the system where 2-D, F-mode, and
M-mode signal processing diverge from PW Doppler and CW
Doppler signal processing. For this reason, it is valuable to check
each mode to see if symptoms that appear are present in each.
For instance, if a 2-D image has noise artifacts in one area of the
image, then placing the PW Doppler cursor in that area provides an
important troubleshooting clue. If the noise is present in both
modes, then it is being introduced at RX board, or earlier in the
processing path (e.g., RX, MX, TX, Power Supplies). If the noise is
only in PW Doppler then it is being introduced in the RX boa rd or
later in the PW signal path (e.g., RX, CSD).
Failures of the RX board are most likely to interrupt a single signal
path to/from the transducer. This is not visually perceptible. If
problems are suspected, replace the board to check for image
improvement.
P/N 59155 Rev. 1 Sequoia Service Training Manual Module 5- 13
Module 5 - System Architecture Acuson Confidential
Failure of the clocks causes the system to stop executing the boot
sequence. The system display and boot appear “dead.”
RI BOARD The Receiver Interconnect board or RI is located on top of the MX
and RX boards in the cardcage. The main functions of this board
are:
• Connects the signal from MX board to the RX board
• Passes clock signal to the MX board
Two versions of the RI boards are available. P/N 31992 is used on
Sequoia 512 ultr asound syst ems, and P /N 35662 is used for Seq uoia
256 echocardiography systems.
Module 5-14 Sequoia Service Training Manual P/N 59155 Rev. 1
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