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EMBEDDED
SOLUTIONS
Case Study - Design and development of Mobile fading
simulator
Customer: Cybernetics
- Japan based company specializing in designing application products
Technology: Embedded; FPGA Design
The Customer
Cybernetics is a niche product company, actively
involved in designing and developing systems such as Mobile Fading
Simulators, Image Processing Systems and micro-controller application
products. The Mobile Fading Simulator is used in the test lab of
a leading cellular service provider in Japan for performing research.
The Challenge
Cybernetics had an existing VME bus-based system,
which used older generation Altera FPGA. This system was very bulky
and the VME bus-based system had become obsolete. The client wanted
to migrate to a Compact PCI-based system, as better support is available
for these systems.
The client provided the block diagram of the multifunction board
that was to form the heart of the system. Tata Infotech had to design
the board, develop the diagnostics for the board, test and debug
the prototype boards. We also had to port the functional FPGA codes
to the new system, which comprised twenty boards. We had to perform
a unit testing of the various FPGA codes, and also execute the onsite
testing and debugging of the entire fading simulator system.
The Solution
The technology used in implementing the solution
was the Mobile Fading Simulator. Tata Infotech prepared the detailed
requirement specification document and the high-level design document
for the multifunction board. The board has two Altera FPGAs Altera
APEX 20KE FPGA (EP20K1500E)-1.5 million-gate FPGA devices. The two
FPGAs communicate with each other over a 16-bit LDVS bus. The FPGAs
interface to EEPROMs, which store look-up tables. These tables are
used by the fading simulator algorithms that run on the board. The
board has a 1.92 Gbps optical interface and a 384 Mbps x 16 bits
LVDS interface. These interfaces are used to interconnect the twenty
multifunction boards that make up the fading simulator. A third
FPGA interfaces the board to the Compact PCI bus.
The multifunction board is 10-layered with a minimum trace width
of 3.94 mils. The EP20K1500E is a 1020-pin FineLine BGA device.
Tata Infotech designed the Printed Circuit Board.
Tata Infotech designed the FPGA diagnostics. Tata Infotech developed
diagnostics to test all the devices on the boards including the
FPGAs, the EEPROMs and the optical transceivers. Diagnostics were
also written to test all the hardware interfaces including the interfaces
between the three FPGAs.
Tata Infotech designed and developed the Windows NT and Windows
2000 device drivers for the multifunction cards. The device driver
allows the host application to access all the FPGA registers, which
are used to set the simulation parameters.
Tata Infotech developed the FPGA code for the Signal Generator
board, the Fading-Attenuation-Delay Board, the Complex Multiplier
Board, the White Gaussian Noise adder board and the DSP Interface
Board. The Signal-Tap feature available with Quartus II software
was used to perform validation of the FPGA codes.
Later, system testing was performed onsite. The fading simulator
comprises of twenty multifunction cards connectors to an embedded
Windows NT/2000 PCs having a Compact PCI back plane. A Windows NT/2000
application exercised the system. The results of simulation in terms
of the output QPSK data is viewed on an oscilloscope with a Digital
to Analog Converter converting the 10-bit, which is selected by
rotary switch, Q and I data values to Analog voltage.
Multifunction Board
The Benefits
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