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Designing Analog Circuits with Ultra-low THD

Monday, February 13, 2017 -
4:00pm to 4:50pm
GLFN AUD (Gilfillan Auditorium)

Speaker Information

Bruce E. Hofer
Audio Precision


Designing an analog circuit with ultra-low THD (<-120 dB) is a challenging, even formidable task.  There are many factors that can limit this aspect of performance including component non-linearity, semiconductor non-linearity, and even mutual inductance.  This introductory seminar will address many of the significant issues facing the designer of such circuits, while also providing a number of useful suggestions.     

Speaker Bio

Bruce is the Chairman and a Co-Founder of Audio Precision.  His primary responsibility is in analog circuit design specializing in ultra-low distortion signal generation, processing, and analysis.  Insiders commonly refer to him as the “precision” in Audio Precision. 


Bruce’s career with state-of-the-art instrumentation began over 48 years ago during the summer of 1968, when he was hired by Tektronix as a student engineering assistant.  After completing his BSEE degree from Oregon State University in 1970, Bruce spent the next 7 years at Tek developing ultra-fast sweep generators and horizontal deflection amplifiers for the “7000-series” oscilloscopes.  In 1978 he became manager and senior engineer of a new group that developed the SG505 low distortion oscillator and the AA501, the world’s first fully automatic distortion analyzer.  Although these plus some follow-on products were market leaders in their day, Tek upper management ultimately decided that audio test products did not fit well into the business strategy of an oscilloscope company.  Thus Bruce and 3 fellow co-workers resigned in 1984, and launched Audio Precision where he remains to this day.       


Bruce has received 13 patents and written many technical articles and papers.  He has been a member of the Audio Engineering Society since 1977, and received its Fellowship Award in 1995 for “Significant Contributions to Audio Measurement Techniques and Technology”.  In 1998 Bruce was inducted into the OSU “Engineering Hall of Fame” during its inaugural year.