Project Files
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DSP-Based Software Radio
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A client was developing a software radio for base station
use. They had done all the system calculations to determine
how the signal path should operate, and what kind of signal
processing they required. They had excellent in-house
expertise for the RF design, but did not have sufficient
in-house experience to do the digital design. |
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System
Overview
The Software Radio required two boards, a Digital board
with the signal acquisition and data processing
hardware, plus a client-designed board with the RF
Front-end, IF stages, and RF Power Amplifier. Bolton
Engineering designed the Digital board around an
Analog
Devices Blackfin® processor running Linux. The system
included 64Mbytes of SDRAM, 64Mbits Serial Flash, a
10/100-Base T Ethernet interface, a Compact Flash Slot
and a moderate-sized Programmable Logic Device (PLD).
The system used the Blackfin PPI to transfer data from
the high speed A/D converter and to the high speed D/A
converter. A system supervisory A/D monitored the
various supply voltages as well as the system
temperature.
In a Software Radio, the clock generator and clock
distribution network are two of the most important
driving factors in determining system performance.
Bolton Engineering designed and simulated the low-phase
noise clock distribution network at the design phase to
ensure the best possible performance. The layout was
carefully segmented and planed to separate the various
design sections. After layout, Bolton Engineering used
Hyperlynx to simulate and verify the system clock tree.
The clock subsystem – and the A/D and D/A subsystems –
were tested to meet the system requirements shortly
after delivery, without requiring subsequent changes.
Project Scope
Bolton Engineering wrote the specification, designed the
schematics, designed the 10-layer Digital circuit board,
worked with the client to define the interface to the RF
board, brought up UBOOT and Linux, wrote diagnostic and
driver software in ‘C’, debugged the system, and
delivered ten working prototypes. The client developed
and maintained the PLD code.
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Consumer and Computer
