Phasor
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Electronic circuit and system design
consulting services
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Employment Projects |
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This page describes projects that
I worked on professionally in positions as Sr. Hardware Designer, Technical
Lead, and Project Engineer before I started my own company. |
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As
well as the hands-on hardware design work described below, I have defined and
overseen the engineering development of a number of projects:
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Data
Converters for Software-Defined Radio. These cards are parts of systems for
digital processing of intermediate-frequency signals up to 70 MHz in
many-channel software-defined radio (SDR) transceivers. They provide
multi-channel A/D and D/A conversion at over 200 megasamples
per second. Features include a phase-locked sampling clock, time-stamping,
and multi-card synchronization. I specified and designed these cards and was
involved in the architectural definition and specification of the rest of the
system. |
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Multichannel
Software-Defined Radio Digitizer. This PCI card filters and coherently
digitizes six intermediate-frequency signals with over 90 dB of spurious-free
dynamic range. Its sampling clock is phase-locked to an external reference,
and the card time-stamps data, with time input from an external GPS receiver.
It has two signal processors and a large dynamic memory store. I specified
the board and designed the analog input, A/D, PLL, and time-stamping
circuitry. |
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Software-Defined
Radio Receiver Library. Developed in C for the TMS320C40 processor, this
library includes functions for channel filtering, demodulation of AM, FM, SSB
and CW signals, baseband filtering, and automatic gain control. I designed
and implemented the algorithms. Matlab was used for
the design of digital filters for this library. |
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Digital
Drop Receiver.
This set of two circuit board modules is used to build multichannel
software-defined radio (SDR) receivers. The high
speed A/D module (right) digitizes the IF signal, from 0.01 to 30 MHz, at 70 megasamples/sec. Many different radio signals may be
present in the sampled digital IF, which is distributed to many Digital Down
Converter (DDC) modules through a 1.4 gigabit/sec coaxial serial link. On each
DDC module (left), the sampled IF is applied to four narrow-band DDC chips,
each of which "channelizes" one radio signal. This involves
converting the signal to baseband I and Q components, digital filtering to
establish the channel bandwidth, and decimating to reduce the sample rate.
Two TMS320C40 DSP's operate on the baseband samples to demodulate four radio
signals simultaneously. My work
included specification, estimation and planning, and project lead of a team
of 3. I designed sections of the DDC module, including the 1.4 gigabit/sec
PECL serial interface and 70 MHz CMOS interface to the DDC chips, and
characterized performance of the A/D module. I development a library of C
functions to control the A/D module and DDC chips, with example programs to
demonstrate down-conversion and spectrum analysis. |
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Autonomous
Precision Approach and Landing System Developed
by Lockheed-Martin, this VME-based avionics system prototype navigated an
aircraft to landing using synthetic-aperture radar, GPS, and inertial
sensors. Working for a subcontractor, I was involved in the design of the
"Digital Electronics Unit" (DEU), which interfaced with a radar
transceiver, inertial measurement unit, radar altimeter, and other avionics.
APALS performed hundreds of successful landings during test flights. The
customer was very pleased with the DEU performance and reliability. Before
approach to an airport, APALS uses GPS to determine it's approximate
position. It then makes synthetic-aperture radar (SAR) images of the ground
every few seconds and correlates these with stored maps to accurately
determine the aircraft position and velocity. A radar altimeter gives
accurate altitude. Between SAR correlation's, aircraft position is updated
based on data from an Inertial Measurement Unit (IMU). During landing,
aircraft navigation is independent of GPS satellites or ground stations. The
system presents information to the pilot on a conventional Instrument Landing
System display and may interface to an autopilot for automatic landing. The
following functions were integrated into the DEU: SPARC system controller Our team
of 4 specified, built, and delivered the DEU hardware in 8 months. My work
included assistance with estimation and planning, specification of the DEU
cards, chassis, and backplane, technical liaison with our customer and the
backplane and chassis subcontractors, and acceptance test planning and
procedures. I designed the analog and discrete I/O circuitry, radar I/Q
digitizer, low-noise power supply, and a test-jig PCB. I wrote test software
in TMS320C40 'C' to exercise the circuitry, made performance measurements,
and did acceptance testing of analog and RF sections of the DEU. Custom DSP Board Custom I/O Board Rear Panel of Custom Chassis |
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DSP
Module with DRAM.
This board combines very large dynamic memory with a DSP, for image
processing and other applications that require large data storage. A 50 MHz
TMS320C40 DSP has access to 128 megabytes of DRAM. Static RAM is also
provided for code storage. I wrote specifications and designed the DRAM
controller section. |
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Audio
Encoder/Decoder.
Developed for the audio section of an ISDN video conferencing system, this IP
module performs G.711/722/728 speech compression using a 40 MHz
floating-point TMS320C31 DSP. I wrote the specifications and designed and
tested the hardware. |
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GMSK
Modem Transition Module. This VME rear panel transition module board provides
analog I/O for interface to a radio transceiver. It works with a DSP IndustryPack module to form the modem in cellular radio
base stations for CDPD data communication. I served as project leader, wrote
specifications, and designed the analog I/O transition module. |
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DSP
Video Processing Board. This PC image-processing board uses a TMS34020
graphics processor to capture video from a camera and display video on a CRT.
A TMS320C31 DSP is used to process images stored in the frame buffer. A
custom high-speed bus allows this card to connect to a mutli-DSP
card for additional processing. I wrote specifications and designed all of
the hardware. |
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Base Station Controller for
Wireless Data. I served as a hardware designer
on the development team for the 2100 Base Station Controller. This VME-based
system with a 68000 processor and a 56001 DSP controlled a radio transceiver
and served as the modem in base stations for Motorola's digital radio
dispatch and data network products. I wrote detailed specifications for the
cards and chassis, designed DSP and I/O circuitry, wrote test software, and
performed accelerated life testing of the completed unit. |
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Video
Controller Chips.
I worked on single-chip ASIC implementations of IBM video controllers for
PC's. As one of a 2-man team, I implemented the "Enhanced Graphics
Adapter" in a 12,000 gate array (left). I was also on a team of 5 that
implemented VGA in a 15,000 gate array (right). My contributions included
specification, logic design, test vector generation, in-house and foundry
simulations, and prototype testing and debugging. |
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(c) Phasor Electronics Design. Oct
2021 |
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