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Keeping up With Signal Processing
Technology
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As processing capability continues to grow,
signal processing systems are using ever
larger amounts of sensor data - in resolution,
bandwidth and number of channels - to perform
their functions. As these systems are being
developed and evaluated, data acquisition and
recording systems are required that can keep
up with the signal processors' capabilities.
Fortunately, the same tools and technologies
that enable faster signal processing systems -
switched fabric interconnect and FPGA-based
processing -can also be used to implement the
data acquisition systems needed to test and
support these advanced systems
The Network Model
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 The
primary mission of a data acquisition system
is to acquire and store data - and lots of it.
The first design parameter to consider is the
amount of data that needs to be stored. If the
application can be implemented with a single
channel to disk (typically up to 200 MB/s),
the system can use either embedded storage
technology or a PC-based data recorder. If the
application requires multiple channels to disk
(from 200 MB/s up to several GB/s), the system
will typically use a switched fabric
interconnect to provide both scalability and
modularity.
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One
benefit of using a switched fabric is the
built in support for a "network model" for the
system as a whole. The system can be viewed as
a loosely coupled set of processing nodes,
each of which has a PowerPC processor, local
memory, I/O module site and bridge to the
fabric.
Nodes can be configured as either storage or
I/O nodes, depending on the type of I/O module
installed. Because each I/O module has its own
dedicated processor, the software model is
very simple. If a Fibre Channel module is
installed, the node acts as a storage server,
responding to client requests through the
fabric network. If an I/O module is installed,
the node acts as both an autonomous I/O server
and a storage client, managing its own I/O
module and requesting storage to disk through
the fabric network.
»More info on JazzStore products
High Speed Fiber Data
In most of the applications Tekmicro
supports, the sensor data being recorded is
converted from analog to digital externally to
the recorder and transferred using high speed
fiber optic interfaces. This approach makes it
easy to insert a data recorder into the system
without degrading the signal integrity of the
data being acquired. The data recorder
typically implements a "copy mode" that
rebroadcasts the input data, allowing the
recorder to be inserted between the sensor and
its signal processor without interrupting the
data flow.
The
most common format for high speed fiber optic
transmission is Serial FPDP, or ANSI / VITA
17.1. Serial FPDP supports 1.062, 2.125 or 2.5
Gbps physical links, providing data rates up
to 247 MB/s per fiber. Serial FPDP is designed
to be a simple, low latency protocol, making
it well suited for FPGA-based implementations.
The
JazzFiber PMC is the building block that
provides high speed fiber interfaces in
Tekmicro's data acquisition systems. Each
module provides four independent fiber optic
interfaces connected to an onboard FPGA. The
module also includes two banks of DDR buffer
memory to support wirespeed buffering of all
four channels of data. When installed on a
PCI-X carrier, the PMC module supports full
throughput (1 GB/s) transfers between all four
channels and the host.
The
FPGA can be used to implement a wide range of
protocols, including Serial FPDP, Fibre
Channel and Gigabit Ethernet, allowing the
same module to support different types of
interfaces through FPGA reconfiguration. Each
processing chain is independent in the FPGA,
allowing a single module to support a mix of
protocols if required.
»More info on JazzFiber |
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Summary
Signal processing systems today make use of
switched fabrics to create modular, scalable
solutions, using FPGA-based processors to
perform processing at higher densities than is
possible with general purpose processors. The
use of the same tools and techniques support a
scalable and flexible approach to building
data acquisition systems. Leveraging COTS
hardware and software, along with tailoring
when necessary through FPGA-based processing,
allows the use of industry standard
components, enclosures, backplanes, I/O
modules and RAID disk arrays. This makes it
possible to develop very high performance data
acquisition and playback systems with
application-specific tailoring where necessary
while reusing existing hardware, software and
FPGA components for the majority of the
system.
»See the Full Article at RTC Magazine.
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About TEK Microsystems, Inc.
Founded in 1981 and headquartered in
Chelmsford, Massachusetts, TEK Microsystems,
Inc., designs, manufactures and markets a wide
range of advanced high-performance boards and
systems for embedded real-time data
acquisition, data conversion, storage and
recording. The Company provides both
commercial and rugged grade products which are
used in real-time systems designed for
applications such as reconnaissance,
electronic warfare, signals intelligence, mine
detection, medical imaging, radar, sonar,
semiconductor inspection and seismic research.
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TEK Microsystems, Inc · 2 Elizabeth
Drive · Chelmsford · MA ·
01824
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