JED - February 2014 - 39


By Ollie Holt

product. Also, third party venders have developed
"cores" that can be purchased or may be available in
"open source."
The first item the survey addresses is board function. There are many different varieties of FPGA
boards. Because FPGAs have become denser (more
capability per chip), the boards can contain more
components, which tends to make them less general purpose and more focused at a specific function
like controllers or signals processors. This category
tries to classify the FPGA board to a function. The
next column defines the manufacturer and type of
FPGA and lists any additional processors, A/Ds and/
or D/As that are included on the board. Defining the
FPGA type aids in determining how much capability
the board may support. It also allows the user to
search for available "cores" that may support the
desired application.
The memory column should be examined in two
ways; some boards will have both the memory contained on the FPGA and additional onboard memory,
while others may just list the additional memory on
the board. Also note the type of memory (FLASH,
RAM, EEPROM, ROM, etc.). The format column basically defines the board size, and if it complies to a
standard format. This is nice to know because it aids
in defining a complete system. The second part of
the complete system equation is the bus format. This
question is addressed in the "format" column, defining the bus and I/O types available. In using these
available boards in the design of an EW system, the
designer should select a bus standard that meets the
needs of the application and a board format that fits
the space available, then select the FPGA and other
support boards that are compatible with the bus and
board format selected.
One last item that should be decided upon when
selecting an FPGA for your design is the support tools.
The major FPGA manufacturers provide tools and evaluation kits for simulating and modeling your design.
Select an FPGA family that has the tools that support
your design needs and also check the availability of
"cores" that can make the design effort easier.
Our next survey, in the March issue, will cover
traveling wave tubes (TWTs) and microwave power
modules (MPMs). Please email
to request a survey questionnaire. a

The Journal of Electronic Defense | February 2014


his month's JED survey looks at Field
Programmable Gate Array (FPGA) boards.
Some of these boards are almost a complete EW receiver and/or technique
generator, only missing the firmware to
configure the FPGA to your task. Some
come with one- or two-channel analog-to-digital
converters (ADCs) only missing the firmware to configure it into a receiver, and others also have a digital-to-analog converter (DAC) so the module could
act as a Digital RF Memory (DRFM) and technique
generator for jamming. Again, the only missing component is the intellectual property (firmware) that
configures the FPGA signal processing to your application. Also some of the larger boards may add a processor for control of these functions.
With the development of high speed ADCs and
digital signal processing algorithms, it is possible to
determine a signal's characteristics with more fidelity than was done in the past with analog and digital
circuits. When high-gate-density gate arrays became
available, they could be configured in pipeline structures that were much faster than performing these
tasks in software. As gate densities increased, fewer
and fewer of these chips were required to perform
the signal processing to the point of only requiring
a single high density component. The other enabler
for this capability was the ability to program them
by the user and not have to order them already configured to your design (as with ASICs). This opened
the market for these components because manufacturers did not need to make the component to meet
the user's needs but could provide a component that
could be configurable to multiple uses.
Over the years, the density has increased to where
they no longer provide gate counts as a factor of density but instead provide Configurable Logic Blocks
(CLB) or Logic Array Blocks (LAB) counts as a factor
of density, and the costs as a function of the number
of CLB's or LAB's has decreased significantly. CLB's
or LAB's are complete functional blocks like adders,
multipliers and even processor cores. Today's FPGAs
also have memory and can even contain a Power PC
core or the more popular MicroBlaze or Nios II processor core. A "core" is a predefined complex function. Most FPGA suppliers have libraries of these
predefined functions available for any user of their



JED - February 2014

Table of Contents for the Digital Edition of JED - February 2014

The View From Here
Conferences Calendar
Courses Calendar
From the President
The Monitor
World Report
Antennas: Shaping the Future of RF Applications
DARPA – No Surprise is the Prize
EW 101
AOC News
Views from the AOC 50th Annual International Symposium and Convention
Index of Advertisers
JED Quick Look
JED - February 2014 - Cover1
JED - February 2014 - Cover2
JED - February 2014 - 3
JED - February 2014 - 4
JED - February 2014 - 5
JED - February 2014 - The View From Here
JED - February 2014 - 7
JED - February 2014 - Conferences Calendar
JED - February 2014 - 9
JED - February 2014 - Courses Calendar
JED - February 2014 - 11
JED - February 2014 - From the President
JED - February 2014 - 13
JED - February 2014 - 14
JED - February 2014 - The Monitor
JED - February 2014 - 16
JED - February 2014 - 17
JED - February 2014 - 18
JED - February 2014 - 19
JED - February 2014 - World Report
JED - February 2014 - 21
JED - February 2014 - Antennas: Shaping the Future of RF Applications
JED - February 2014 - 23
JED - February 2014 - 24
JED - February 2014 - 25
JED - February 2014 - 26
JED - February 2014 - 27
JED - February 2014 - DARPA – No Surprise is the Prize
JED - February 2014 - 29
JED - February 2014 - 30
JED - February 2014 - 31
JED - February 2014 - 32
JED - February 2014 - 33
JED - February 2014 - EW 101
JED - February 2014 - 35
JED - February 2014 - 36
JED - February 2014 - AOC News
JED - February 2014 - Views from the AOC 50th Annual International Symposium and Convention
JED - February 2014 - 39
JED - February 2014 - 40
JED - February 2014 - Index of Advertisers
JED - February 2014 - JED Quick Look
JED - February 2014 - 43
JED - February 2014 - 44
JED - February 2014 - 45
JED - February 2014 - 46
JED - February 2014 - 47
JED - February 2014 - 48
JED - February 2014 - 49
JED - February 2014 - 50
JED - February 2014 - Cover3
JED - February 2014 - Cover4