Albert D. Helfrick

Amateur Radio Equipment Fundamentals

Albert D. Helfrick, 1981 .

Modern Aviation Electronics

Albert D. Helfrick, A. Helfrick, 1984 .

Electronics in the Evolution of Flight

Albert D. Helfrick, 2004 .

3 – Frequency Control, Phase Lock, and Microprocessor-Controlled Spectrum Analyzers

Albert D. Helfrick, 1991 .

Electrical Spectrum and Network Analyzers: A Practical Approach

Albert D. Helfrick, 1991 .

Modern Electronic Instrumentation and Measurement Techniques

Albert D. Helfrick, William David Cooper, William David Cooper, 2008 .

9 – The Network Analyzer

Albert D. Helfrick, 1991 .