James Long, Ph.D., P.E. Retired Analog and RF Consulting Engineer

Typical Projects

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Here is a list of some typical projects segregated into three size groups: small (under 30 hours), medium (30-300 hours), and large (over 300 hours.)

Small Projects

Zero drift in crack detector The phase shift in the coupling coefficient between two coils was used to detect the presence of a crack in magnetic material near the coils. The phase shift of the signal path was not stable. I made several corrections to make it stable.

High temperature errors in optical data link Pulse width modulation was used to distinguish between ones and zeros in an optical data link. The pulse widths were temperature sensitive. I changed several parts in the modulator without changing the surface mount PC card pattern.

Cost reduction on antenna range The null tracking electronics for a monopulse antenna measurement range was too expensive. I re-specified them to still meet the performance, but at a lower (half) price.

ESD problems on flat panel display The display flickered and had horizontal lines during ESD pulses. I added several bypass capacitors and ferrite beads to eliminate the cosmetic problem.

Herding equipment through FCC and CE EMI tests On numerous occasions I have added copper foil, ferrite beads, and bypass capacitors during the preliminary tests to allow equipment to pass the official tests.

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Medium Projects

NASA voice disguiser for a radio channel simulator. This allowed a few people to simulate radio traffic on a flight route for safety tests.

Baseball bat speed sensor This unit was hidden in a home plate and was able to measure bat speed in all sunlight conditions.

Track and field timer IR light beams were sent across a track at different places and radioed back to a central stop watch whenever a runner went by.

CCD still camera I did part of the system design for a CCD still camera before the accountants at the customer decided that there was no future sales volume in digital still cameras and canceled the project.

Particle detector redesign for CE The power supply and interface circuitry was redesigned to meet the safety and conducted EMI requirements for CE

IR data link I designed a totally transparent analog in analog out IR link that emulated a wire. It was connected between a serial port on one computer and a serial port on another computer. The bit rate could be as high as 250k/s. The physical range was 40 feet. This was used on a large X-Y robot that put boxes in and out of shelf location storage areas on a factory wall.

600 W RF source This was a megasonic source for driving piezoelectric transducers for cleaning purposes.

T1 data over the analog telephone subscriber loop This was a loose ends clean up project to take care of all of the not yet discovered errors on a large project.

Range simulator for Satellite Earth Station This took a video frequency range of signals extending to DC and changed the amplitude and delay in precisely controlled fashion. It fit on a medium size PC card.

Miniature ADC system on a PC104 card for PCs A multichannel ADC data acquisition system with ranging and calibration built in.

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Large Projects

Radiation Tolerant Design This was a project for the Department of Energy SP-100 space satellite atomic power source. A 100 kW electric atomic to electric power generator was to be used to power space satellites. Since radiation shielding was expensive to lift into space the power source was 100 m away from the satellite on a boom. The power source had to be monitored. I designed the sensor amplifiers and multiplexers to transport the data on few (instead of a few hundred) cables that went down the 100 m boom. The radiation intensity at the generator end caused a cumulative radiation dose 10X lager than anything before. The system parts were constructed and survived a radiation test.

Cable Modem This was the first cable modem to run at multi-megabit rate. It was used in a broad band cable telephone system. The customer went public, but also went bankrupt after 11 years of misjudging the market and attempting to sell grandiose products when the customers wanted simple ones.

Chirp RADAR Receiver for the Eastern Test Range. I designed the entire receiver from the feed horn to the I and Q inputs to the ADCs for the DSP processing.

Remote Measurement and Logging system This was a loose ends tying up project on an existing design that did not work to the client's customers constantly moving target and "oh by the way's."

Passive, noncontact electronic access keys Over a period of several years I was called in to redesign the card readers for both the analog and the digital cards. The reading distance was eventually doubled.

Portable Direction Finding Receiver This system design had been used for several years by the military. I did the final pass of the system removing all of the spurious responses and other shortcomings in the 0.1 - 2000 MHz receiver.

Land Warrior I designed the voice and data radio for both version 0.6 and 1.0 (experimental development). The system uses a 802.11 protocol commercial card. This system has a lot of potential once further development reduces the size, weight, power drain, and complexity. It also needs a military grade jam-proof protocol and modulation format.

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