Curriculum Vitae

W. Marshall Leach, Jr., Professor
Georgia Institute of Technology
School of Electrical & Computer Engineering
Atlanta, Georgia 30332-0250

Education


Employment History


Experience Summary

Experience at NASA consisted of construction and evaluation of bi-phase PCM modulators.

Experience in the U.S. Air Force consisted of nuclear pulse detection, counting, and spectroscopy; pulse electronics; mass spectrometer instrumentation and automation; and ion detection in ultra high vacuum systems.

Experience at Georgia Tech Research Institute consisted of antenna design, construction, and evaluation, and near-field antenna measurements.

Experience at Georgia Tech School of Electrical and Computer Engineering consists of teaching in the areas of audio, electronics, instrumentation, electroacoustics, and electromagnetics; participating in the development of a graduate Acoustical Engineering Program in the College of Engineering; development of senior courses in Audio Engineering and a laboratory course in Transistor Circuits; performing research in the areas of near-field acoustic measurements, near-field electromagnetic measurements, instrumentation for electromagnetic susceptibility testing, low intermodulation distortion RF power amplifier development, development of instrumentation for ground-loop current detection and measurement, audio power amplifier design techniques, loudspeaker system design, and analog and digital audio signal processor design; and development of an Audio Laboratory under a National Science Foundation grant.


Current Fields of Interest

Electromagnetic theory, audio, electroacoustics, electronic circuit design, instrumentation, low noise electronic design, and electromagnetic compatibility.


Patents

United States Patent 4,284,860, "Time Domain Measurement of Moving Coil Loudspeaker Driver Parameters," August 18, 1981, Co-inventor was Ronald W. Schafer, assigned to Georgia Tech Research Institute.


Honors and Awards


Professional Affiliations


Publications

Theses

  1. W. M. Leach, Jr., "An Investigation of Defocus Phase Errors in Paraboloidal Reflectors," M.S. Thesis, University of South Carolina, 1964.
  2. W. M. Leach, Jr., "Probe Compensated Near-Field Measurements on a Cylinder," Ph.D. Dissertation, Georgia Institute of Technology, 1972.

Books and Contributions to Books

  1. W. M. Leach, Jr., McGraw-Hill Encyclopedia of Science, articles titled "Loudspeaker," "Volume Control," and "Volume Unit (VU) Meters," New York: McGraw-Hill Professional, 2002, ISBN 0079136656.
  2. W. M. Leach, Jr., Introduction to Electroacoustics and Audio Amplifier Design, Third Edition, Dubuque, Iowa: Kendall/Hunt, 2001, ISBN 9-780757-503757.
  3. W. M. Leach, Jr., article titled "Circuit Noise," in The Wiley Encyclopedia of Electrical and Electronics Engineering, vol. 3., edited by John G. Webster, New York: John Wiley, 1999, ISBN 0-471-13946-7.
  4. W. M. Leach, Jr., article titled "Noise Measurements," in The Measurement, Instrumentation, and Sensors Handbook, edited by John G. Webster, Boca Raton, Florida: CRC Press, 1999. ISBN 0-8493-8347-1

Journal Papers and General Articles

  1. W. M. Leach, Jr., "Impedance Compensation Networks for the Lossy Voice-Coil Inductance of Loudspeaker Drivers," Journal of the Audio Engineering Society, vol. 52, no. 4, pp. 358-365, Apr. 2004.
  2. A. E. Ginart, R. M. Bass, W. M. Leach, Jr., T. G. Habetler, "Analysis of the class AD audio amplifier including hysteresis effects," IEEE Transactions on Power Electronics, vol. 18, no. 2, pp. 679-685, March 2003.
  3. W. M. Leach, Jr., "Loudspeaker Voice-Coil Inductance Losses: Circuit Models, Parameter Estimation, and Effect on Frequency Response," Journal of the Audio Engineering Society, vol. 50, no. 6, pp. 442-450, June 2002.
  4. W. M. Leach, Jr., "Noise Relations for Parallel Connected Transistors," J. Audio Engr. Soc., Vol. 47, No. 3, pp. 112-118, March 1999.
  5. W. M. Leach, Jr., "Electronic Technology," J. Audio Engr. Soc., Vol. 46, No. 1/2, pp. 59-70, Jan./Feb. 1998.
  6. W. M. Leach, Jr., "On the Application of Thevenin and Norton Equivalent Circuits and Signal Flow Graphs to the Small-Signal Analysis of Active Circuits," IEEE Transactions on Circuits and Systems I, Vol. 43, No. 11, pp. 885-893, Nov. 1996.
  7. W. M. Leach, Jr., "A two-port analogous circuit and SPICE model for Salmon's family of acoustic horns," Journal of the Acoustical Society of America, Vol. 99, No. 3, pp. 1459-1464, March 1996.
  8. W. M. Leach, Jr., "On the Calculation of Noise in Multistage Amplifiers," IEEE Transactions on Circuits and Systems I, vol. 42, No. 3, pp. 176-178, March 1995.
  9. W. M. Leach, Jr., "SPICE Models for Vacuum Tube Amplifiers," Journal of the Audio Engineering Society, vol. 43, No. 3, pp. 117-126, March 1995.
  10. W. M. Leach, Jr., "Fundamentals of Low-Noise Analog Circuit Design," Proceedings of the IEEE, vol. 82, No. 10, pp. 1515-1538, Oct. 1994.
  11. W. M. Leach, Jr., "Controlled-Source Analogous Circuits and SPICE Models for Piezoelectric Transducers," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 41, No. 1, pp. 60-66, Jan. 1994.
  12. W. M. Leach, Jr., "A Four-Stage FM Broadcast Audio Peak Limiter," IEEE Transactions on Broadcasting, vol. 38, No. 1, pp. 55-59, March 1992.
  13. W. M. Leach, Jr., "Noise Analysis of Transformer Coupled Preamplifiers,"Journal of the Audio Engineering Society, vol. 40, no. 1/2, pp. 3-11, January/February 1992.
  14. W. M. Leach, Jr., "Computer-Aided Electroacoustic Design with SPICE," Journal of the Audio Engineering Society, vol. 39, no. 7/8, pp. 551-563, July/August 1991.
  15. W. M. Leach, Jr., "On the Electroacoustic-Analogous Circuit for a Plane Wave Incident on the Diaphragm of a Free-Field Pressure Microphone," Journal of the Audio Engineering Society, vol. 38, no. 7/8, pp. 566-568, July/August 1990.
  16. W. M. Leach, Jr., "A Generalized Active Equalizer for Closed-Box Loudspeaker Systems," Journal of the Audio Engineering Society, vol. 38, no. 3, March 1990.
  17. W. M. Leach, Jr., "The Differential Time-Delay Distortion and Differential Phase-Shift Distortion as Measures of Phase Linearity," Journal of the Audio Engineering Society, vol. 37, no. 9, pp. 709-715, September 1989.
  18. Dan Mapes-Riordan and W. M. Leach, Jr., "The Design of a Digital Signal Peak Limiter for Audio Signal Processing," Journal of the Audio Engineering Society, vol. 36, no. 7/8, pp. 562-574, July/August 1988.
  19. W. M. Leach, Jr., "Electroacoustic-Analogous Circuit Models for Filled Enclosures," Journal of the Audio Engineering Society, vol. 37, no. 7/8, pp. 586-592, July/August 1989.
  20. W. M. Leach, Jr., "The Audio Laboratory Loudspeaker System," Speaker Builder, vol. 10, no. 2, pp. 10-12, 14, & 70, March 1989.
  21. W. M. Leach, Jr., "Feedforward Compensation of the Amplifier Output Stage for Improved Stability with Capacitive Loads," IEEE Transactions on Consumer Electronics, vol. 34, no. 2, pp. 334-338, May 1988.
  22. W. M. Leach, Jr., "Electroacoustic System Realizations for the Linkwitz-Riley Crossover Networks," Journal of the Audio Engineering Society, vol. 35, no. 10, pp. 792-800, October 1987.
  23. W. M. Leach, Jr., "Author's Reply to Comments on 'An Amplifier Input Stage Design Criterion for the Suppression of Dynamic Distortions'," Journal of the Audio Engineering Society, vol. 34, no. 5, pp. 355-359, May 1986.
  24. W. M. Leach, Jr., "Author's Reply to Comments on 'Reactance Annulling in Horn-Loaded Loudspeaker Systems'," Journal of the Audio Engineering Society, vol. 29, no. 7/8, pp. 523-524, July/August 1981.
  25. W. M. Leach, Jr., "Active Equalization of Closed-Box Loudspeaker Systems," Journal of the Audio Engineering Society, vol. 29, no. 6, pp. 405-407, June 1981.
  26. W. M. Leach, Jr., "An Amplifier Input Stage Design Criterion for the Suppression of Dynamic Distortions," Journal of the Audio Engineering Society, vol. 29, no. 4, pp. 249-251, April 1981.
  27. W. M. Leach, Jr., "Comments on 'Acoustic Radiation of a Horn Loudspeaker by the Finite Element Method - A Consideration of the Acoustic Characteristic of Horns'," Journal of the Audio Engineering Society, vol. 28, no. 12, p. 900, December 1980.
  28. W. M. Leach, Jr., "Loudspeaker Driver Phase Response: The Neglected Factor in Crossover Network Design," Journal of the Audio Engineering Society, vol. 28, no. 6, pp. 410-421, June 1980.
  29. W. M. Leach, Jr., Book Review, IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. ASSP-28, pg. 350, June 1980.
  30. W. M. Leach, Jr., "Build a Double Barreled Amplifier - Part II," Audio , vol. 64, no. 5, pp. 44-60, May 1980.
  31. W. M. Leach, Jr., "Build a Double Barreled Amplifier - Part I," Audio, vol. 64, no. 4, pp. 36-51, April 1980.
  32. W. M. Leach, Jr., "On the Specification of Moving-Coil Drivers for Low-Frequency Horn-Loaded Loudspeakers," Journal of the Audio Engineering Society, vol. 27, no. 12, pp. 950-959, December 1979.
  33. W. M. Leach, Jr., R. W. Schafer, and T. P. Barnwell III, "Time-Domain Measurement of Loudspeaker Driver Parameters," IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. ASSP-27, no. 6, pp. 734-739, December 1979.
  34. W. M. Leach, Jr., "Comments on 'Integral Equation Formulation for Probe Corrected Far-Field Reconstruction from Measurements on a Cylinder'," IEEE Transactions on Antennas and Propagation, vol. AP-27, no. 6, pp. 895-897, November 1979.
  35. W. M. Leach, Jr., "Build an Amplifier Strapping Circuit," Audio, vol. 63, no. 2, pp. 40-43, February, 1979.
  36. W. M. Leach, Jr., "Build a Stepped Volume Control," Audio, vol. 63, no. 2, pp. 44-46, February 1979.
  37. W. M. Leach, Jr., "Comments on 'VHF and UHF Links Using Mountains as Reflectors'," IEEE Transactions on Communications, vol. COM-27, no. 1, p.255, January 1979.
  38. W. M. Leach, Jr., "Author's Reply to Comments on Suppression of Slew Rate and Transient IM Distortions in Audio Power Amplifiers'," Journal of the Audio Engineering Society, vol. 26, no. 6, p. 453, June 1978.
  39. D. T. Paris, W. M. Leach, Jr., and E. B. Joy, "Basic Theory of Probe Compensated Near-Field Measurements," IEEE Transactions on Antennas and Propagation, vol. AP-26, no. 3, pp. 373-379, May 1978. (Invited)
  40. E. B. Joy, W. M. Leach, Jr., G. P. Rodrigue, and D. T. Paris, "Applications of Probe-Compensated Near-Field Measurements," IEEE Transactions on Antennas and Propagation, vol. AP-26, no. 3, pp. 379-389, May 1978. (Invited)
  41. J. E. Weaver and W. M. Leach, Jr., "Optical Measurement of Loudspeaker Driver Large Signal Displacement," Journal of the Audio Engineering Society, vol. 26, no. 3, pp. 145-148, March 1978.
  42. W. M. Leach, Jr., "Build a Pre-Preamp for Moving Coil Pickups," Audio, vol. 62, no. 2, pp. 36-40, February 1978.
  43. W. M. Leach, Jr., "Suppression of Slew-Rate and Transient IM Distortions in Audio Power Amplifiers," Journal of the Audio Engineering Society, vol. 25, no. 7, pp. 466-473, July/August 1977.
  44. W. M. Leach, Jr., "Construct a Wide Bandwidth Preamplifier," Audio, vol. 61, no. 2, pp. 38-48, February 1977.
  45. W. M. Leach, Jr., "Low TIM Amplifier - Part II," Audio, vol. 61, no. 2, pp. 48-56, February 1977.
  46. W. M. Leach, Jr., Book Review, Proceedings of the IEEE, vol. 64, no. 3, p. 396, March 1976. (Reprinted from the IEEE Antennas and Propagation Society Newsletter, October 1975.
  47. W. M. Leach, Jr., "Build a Low TIM Amplifier," Audio, vol. 60, no. 2, pp. 30-46, February 1976.
  48. W. M. Leach, Jr., "Transient IM Distortion in Power Amplifiers," Audio, vol. 59, no. 2, pp. 34-41, February 1975.
  49. W. M. Leach, Jr. and D. T. Paris, "Probe-Compensated Near-Field Measurements on a Cylinder," IEEE Transactions on Antennas and Propagation, vol. AP-21, no. 4, pp. 435-445, July 1973.

Conference Presentations with Proceedings

  1. Dan Mapes-Riordan and W. M. Leach, Jr., "The Design of a Digital Signal Peak Limiter for Audio Signal Processing," presented at the 83rd Convention of the Audio Engineering Society, Preprint No. 2494, October 1987.
  2. V. K. Jain, W. M. Leach, Jr., and R. W. Schafer, "Time Domain Measurement of Vented-Box Loudspeaker System Parameters," 1981 International IEEE ASSP Conference Record, pp. 494-497, April 1980.
  3. W. M. Leach, Jr., "The Spatial Alignment of Loudspeaker Drivers on a Baffle-Effects on System Amplitude and Phase Responses," 1980 International IEEE ASSP Conference Record, Colorado Springs, Colorado, pp. 494-497, April 1980.
  4. W. M. Leach, Jr., "Loudspeaker Drive Phase Response: The Neglected Factor in Crossover Network Design," presented at the 64th Convention of the Audio Engineering Society, New York, New York, Preprint No. 1538, November 1979.
  5. W. M. Leach, Jr., R. W. Schafer, and T. P. Barnwell, "Time Domain Measurement of Loudspeaker Driver Parameters," 1979 International IEEE ASSP Conference Record, Washington, D.C., pp. 322-325, April 1979.
  6. W. M. Leach, Jr., "On the Specification of Moving-Coil Drivers for Low-Frequency Horn-Loaded Loudspeakers," presented at the 61st Convention of the Audio Engineering Society, New York, New York, Preprint No. 1405, November 1978.
  7. W. M. Leach, Jr., "Relationships Between Amplifier Bandwidth, Slew Rate Requirements, and Phase Distortion," presented at the 61st Convention of the Audio Engineering Society, New York, New York, Preprint No. 1415, November 1978.
  8. W. M. Leach, Jr., "Design Considerations or Feedback Amplifiers," 1978 International IEEE ASSP Conference Record, Tulsa, Oklahoma, pp. 252-254, April 1978.
  9. W. M. Leach, Jr., "Correction of Near-Field Acoustic Measurements made with Arbitrary Measuring Transducers," 1978 International IEEE ASSP Conference Record, Tulsa, Oklahoma, pp. 832-835, April 1978.
  10. W. M. Leach, Jr., Suppression of Slew Rate and Transient IM Distortions in Audio Amplifiers," presented at the 55th Convention of the Audio Engineering Society, New York, New York, Preprint No. 1137, October 1976.
  11. J. E. Weaver and W. M. Leach, Jr., "Optical Measurement of Loudspeaker Driver Large Signal Displacement Parameters," presented at the 55th Convention of the Audio Engineering Society, New York, New York, Preprint No. 1163, October 1976.
  12. W. M. Leach, Jr., E. B. Joy, and D. T. Paris, "Probe Compensated Near-Field Measurements: Basic Theory, Numerical Techniques, Accuracy," 1974 International IEEE AP-S Symposium Digest, Atlanta, Georgia, pp. 155-157, June 1974.

Conference Presentations without Proceedings

Research Reports

  1. T. E. Brewer, A. M. Bush, D. J. Healy, and W. M. Leach, Jr., "Preliminary Concept Script of the National Science Center for Communications and Electronics," Final Report to National Science Center for Communications and Electronics, Contract No. DAAG29-81-D-0100, 1986.
  2. T. E. Brewer, A. M. Bush, D. J. Healy, and W. M. Leach, Jr., "Information Base for the Transmission Gallery of the National Science Center for Communications and Electronics," Intermediate Report to National Science Center for Communications and Electronics, Contract No. DAAG29-81-D-0100, 1986.
  3. T. E. Brewer and W. M. Leach, Jr., "Grounding, Bonding, Shielding, and Lightning Bibliography," Final Report to Rome Air Development Center, Contract F30602-78-C-0120, Tasks PR N-0-5126 and PR N-9-5294, 1980.
  4. D. K. Plummer, J. E. Rhodes, W. M. Leach, Jr., B. R. Livesay, H. M. Harris, J. J. Earshen, T. E. Brewer, M. D. Blue, and W. E. Baird, "Underwater Electronic Systems Investigations," Final Report to Naval Coastal Systems Center, Contract N61339-75-C-0122, Delivery Order No. HR-46, May 1979.
  5. W. M. Leach, Jr. and L. N. An, "Cylindrical Wave Study," Final Report to NASA, Contract NAS5-23886, April 1978.
  6. W. M. Leach, Jr., T. E. Brewer, and M. R. Walls, Jr., "An Investigation of Low-Frequency Electroacoustic Transducers for Underwater Sound Generation," Final Report to Naval Coastal Systems Laboratory, Contract N61339-75-C-0122 HR-36, March 1978.
  7. E. B. Joy, G. K. Huddleston, W. M. Leach, Jr., R. F. Hochman, J. G. Rinker, M. Marek, and K. J. Bundy, "A High-Current Minesweeping Electrode Investigation," Final Report to Naval Coastal Systems Laboratory, Contract N61339-75-C-0122 HR-07, June 1976.
  8. E. B. Joy, W. M. Leach, Jr., G. K. Huddleston, W. J. Barnes, R. E. Wilson, R. F. Hochman, M. Marek, J. G. Rinker, and K. J. Bundy, "Final Design and Analysis of High Current Minesweeping Electrodes," Final Report to Naval Coastal Systems Laboratory, Contract N61339-75-C-0122 HR-24, January 1978.
  9. W. M. Leach, Jr., "Correction of Near-Field Acoustic Measurements Made With Arbitrary Measuring Transducers," Final Report to National Science Foundation, Grant GK42119, March 1976.
  10. J. L. Edwards, C. E. Ryan, Jr., W. M. Leach, Jr., and W. J. Storey, "Near-Zone Radar Cross-Section Technique Development," Technical Report to Air Force Avionics Laboratory, Contract AFAL-TR 74-227, November 1974.

Research Proposals

  1. "Two Dimensional Signal Processing and Storage and Theory and Applications of Electromagnetic Measurements", Joint Services Electronics Program, $1,507,561 (Proposal written jointly with Professors Mersereau, Schafer, Barnwell, Gaylord, Rhodes, Smith, Norgard, Joy, and Huddleston), July 1980.
  2. "Underwater Electronic Systems Investigations", Naval Coastal Systems Center, $7,374 (EE share of proposal written jointly with the Engineering Experiment Station), April 1978.
  3. "Theory and Applications of Electromagnetic Measurements", Office of Naval Research, Air Force Office of Scientific Research, and Army Research Office, $349,999 (Proposal written jointly with Professors D.T. Paris, R.K. Feeney, G.K. Huddleston, E.B. Joy, J.D. Norgard, G.P. Rodrigue, and G.S. Smith), March 1978.
  4. "An Investigation of Electroacoustic Radiators for Low-Frequency Underwater Sound Generation", Naval Coastal Systems Center, $24,643, June 1977.
  5. "Cylindrical Wave Expansion Study", NASA, $25,614, December 1976.
  6. "An Undergraduate Instructional Laboratory in Audio and Electroacoustics", National Science Foundation, $20,000 (plus $20,000 in Institute matching funds), February 1974.
  7. "Correction of Near-Field Acoustical Measurements Made with Arbitrary Measuring Transducers", National Science Foundation, $17,000, December 1973.
  8. "Microphone Compensation in Near-Field Acoustical Measurements", National Science Foundation, $17,000, December 1972.

Research Grants Funded (Principal Investigator)

  1. "Grounding, Bonding, Shielding and Lightning Bibliography 1972 to 1979", Federal Aviation Administration, $33,000, June 1979/February 1980 - December 1980.
  2. "TEMPEST Testing Evaluation and Recommendations", USAF Hanscom Field (RADC/ET), $13,000, March 1979 - September 1979.
  3. "Integrated Hardware/Software and Targeting Systems Development for EMR Testing of Weapon Systems", USAF Rome Air Development Center, $80,000 ($51,000 of this was for the Engineering Experiment Station), March 1979 - September 1979.
  4. "Underwater Electronic Systems Investigations", Naval Coastal Systems Center, $7,374 (EE share of contract performed jointly with the Engineering Experiment Station. Was Co-Principal Investigator responsible for electromagnetic and acoustic parts of the task), June 1978 - August 1978.
  5. "An Investigation of Electroacoustic Radiators for Low-Frequency Underwater Sound Generation", Naval Coastal Systems Center, $24,643, August 1977 - February 1978.
  6. "Cylindrical Wave Expansion Study", NASA Goddard Space Flight Center, $25,000, January 1977 - January 1978.
  7. "Electronic Systems", USAF Rome Air Development Center, $7,000, May 1977 - January 1978.
  8. "Electronic Systems", USAF Rome Air Development Center, $12,000, May 1976 - September 1976.
  9. "A Heterodyne Ground Current Analyzer", USAF Communications Service, $5,000, October 1975 - April 1976.
  10. "Electronic Systems", USAF Rome Air Development Center, $15,000, May 1975 - September 1975.
  11. "Correction of Near-Field Acoustical Measurements Made with Arbitrary Measuring Transducers", National Science Foundation, $17,000, September 1974 - February 1976.
  12. "Information Base and Concept Script for the Transmission Gallery of the National Science Center for Communications and Electronics", U.S. Army, $25,299, 1986.
  13. "An Undergraduate Instructional Laboratory in Audio and Electroacoustics", National Science Foundation, $20,000 (Plus $20,000 in Institute matching funds), June 1974.
  14. "A Low Intermodulation RF Amplifier", Federal Aviation Administration, $17,000, June 1974 - December 1974.
  15. "Electronic Systems", USAF Rome Air Development Center, $15,000, May 1974 - September 1974.
  16. "Electronic Systems", USAF Rome Air Development Center, $15,000, May 1973 - September 1973.
  17. "Electronic Systems", USAF Rome Air Development Center, $30,000, September 1972 - May 1973.

Research Grants (Contributor)

  1. "Information Base and Concept Script for the Transmission Gallery of the National Science Center for Communications and Electronics," U.S. Army, $25,299, 1986.
  2. "Two-Dimensional Signal Processing and Storage and Theory and Applications of Electromagnetic Measurements", Joint Services Electronics Program, $957,382 (Supported eight work units), January 1978 - 1984. (Member of a three-man work unit entitled "Automated Radiation Measurements for Near and Far-Field Transformations".)
  3. "Final Design and Analysis of High-Current Minesweeping Electrodes", Naval Coastal Systems Center, $53,895, January 1977 - July 1977.
  4. "A High-Current Minesweeping Electrode Investigation", Naval Coastal Systems Center, $30,000, March 1976 - June 1976.
  5. "Near-Field Radar Cross-Section Technique Development", USAF Avionics Laboratory, Contract with the Engineering Experiment Station, March 1973 - April 1974.

Continuing Education


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