Analog and Digital Systems Group
Analog and Mixed-Signal Circuit Design
Oak Ridge National Laboratory When possible, ADS engineers
(ORNL) researchers, because of the perform board- and system-level
unique and leading-edge nature of design using commercially available
their investigations, often encounter sensors, integrated circuits, modules,
situations in which no commercially and subsystems to reduce cost. Other
available instrumentation meets their MSSE and Laboratory resources are
measurement needs. In other cases, tapped when the use of custom
researchers’ goals are to advance the sensors, materials, or integrated
state of the art by increasing the circuits is beneficial.
Purpose: When ORNL
range, resolution, or accuracy of
Development of “front-end” circuitry
When researchers, industrial scientific measurements in their fields
such as sensor excitation and signal
State of the
partners, or colleagues of expertise. Sometimes the sheer
from government or conditioning is accelerated by
number of measurements required to
Art military agencies have
a unique measurement collect all required data or to properly modeling with PSPICE and similar
Is Not Quite requirement, the ADS control an experiment precludes the simulation packages. Modeled
Enough Group has the expertise
and the experience to use of off-the-shelf instruments. designs import easily into printed-
move the requirement circuit layout software for rapid
from a concept to a The Analog and Digital Systems production of prototype boards.
implementation in a (ADS) Group stands ready to partner Small quantities of circuit boards and
laboratory or in the with these scientists and provide instruments are usually built in-
field. electronics development and other house. Larger quantities are usually
ADS’s analog and measurements-related capabilities outsourced to trusted fabrication
design capabilities that will enable their research to houses.
effectively bridge the move forward.
gap between unusual Success Story: DDS Mass
sensors and the latest Capabilities Spectrometer
data acquisition and
control systems in an ADS has established expertise in the Spectrometrists in the Chemical
impressive variety of following areas critical to scientific Sciences Division had a great idea:
R&D applications. measurement, data acquisition, and use Direct Digital Synthesis (DDS) to
Complementary control: generate the frequencies used for
analog and mixed- • Sensor-electronics integration. exciting the electrodes in a digital ion-
circuit design expertise trap mass spectrometer. DDS would
meshes well with other • High-precision data conversion. allow the frequencies to be varied in
ADS and MSSE
strengths in the • Data multiplexing and telemetry. arbitrarily small steps, greatly
following: increasing the resolution of the
• Low-noise signal conditioning of
• RF circuit and measurement.
antenna design. high-speed and low-level signals.
• Sensor development.
• High-voltage biasing and pulsing. The catch? To capitalize on the
computation. • Board- and system-level design. frequency selectivity and stability
• Programmable offered by the DDS approach,
device applications. • Electromagnetic emissions and extremely stable high-voltage
intelligence. susceptibility control. supplies, extremely fast high-voltage
• Power electronics.
• Optics and image
• Efficient power conversion and pulsing, and extremely low-jitter
processing. distribution. generation and distribution of the
• Electronic signature clock and switching signals were
analysis. • Interfacing disparate systems.
• Radiation detection required. In addition to implementing
and characterization. • Built-in test and calibration. the DDS and clock-generation
• Wireless sensor networks. algorithms in a field-programmable
gate array (FPGA), ADS developed
Analog and Digital Systems Group
the power conditioning and high-voltage switching delivering them from a depth of 100 meters and over
circuitry that completed the package. When the ADS distances of up to a kilometer to the USNS Hayes, the
prototype circuit board was used to replace the Navy’s noise analysis laboratory ship.
electronics in a modern laboratory-grade mass spec, an
immediate 5× resolution improvement was realized. Every link of the signal processing chain had to be ultra-
accurate to maintain the precise gain and phase
relationships between hydrophone signals that allow the
topside computers to form the arrays’ sensitivity
patterns into the narrow beams required to attenuate the
ocean’s background noise and to focus on specific
portions of the submarine being tested.
Powering thousands of channels of electronics through
kilometers of cables presented another set of challenges.
The use of 300-VDC power transmission through the
umbilical cables minimizes power loss in the cables but
requires conversion to much lower voltages inside the
underwater pressure vessels. The ADS-developed power
conversion and conditioning subsystem delivers the
Separation of the isotope peak in this segment low-noise power required for precise amplification,
of a DDS mass spectrum for perfluorotributylamine filtering, and digitization. It also achieves the high
is clearly evident.
efficiency required for keeping the signal conditioning
and data telemetry electronics cool, ensuring high
Another 5× increase in resolution is expected in the next reliability and long life.
generation of the DDS timing circuitry.
For over a decade now, the AMFIP II system has been
Success Story: Acoustic Measurements used by the Navy to ensure that our nation’s submarine
Facilities Improvement Program, Phase II fleet keeps its edge by maintaining its silence.
The U.S. Navy faced a dilemma: The new Seawolf class
of fast-attack submarines being planned was going to be
so stealthy that no existing noise-measurement sonar
system would be able even to verify that the new boats
met their unprecedented noise-generation specifications.
The Navy turned to ORNL for assistance, and ADS
personnel, members of the Real-Time Systems Group,
and industrial partner Planning Systems, Incorporated,
worked together to develop the most sensitive sonar
system ever deployed. Considering that the acoustic
noise levels emitted by the Seawolf are considerably
lower than the background noise levels even in the
quietest seas on the planet, the challenge of not only
detecting these emissions but of accurately measuring Nighttime deployment of an HGA
from the USNS Hayes.
them over a wide bandwidth was daunting.
MSSE’s Real-Time Systems Group led the effort to Contact Information
develop the data acquisition and analysis system based For more information on ADS’s analog and mixed-signal
on two Cray SuperServer highly paralleled processors. development capabilities, please contact William H.
ADS members took responsibility for conditioning and (Andy) Andrews (firstname.lastname@example.org) at
digitizing signals from the three 10-meter-tall, 865-574-5677 or Dwight Clayton (email@example.com)
1,000-hydrophone high-gain arrays (HGAs) and at 865-576-8134.