Design and Evaluation of an Audio-Frequency Transresistance Amplifier for Magnetic Tape Playback

Salvatierra, Thomas R. M.S.Egr., Department of Electrical Engineering, Wright State University, 2011. Design and Evaluation of an Audio-Frequency Transresistance Ampli er for Magnetic Tape Playback. Analog magnetic tape remains a medium of choice for highdelity sound recording and reproduction. Some of this delity is sacri ced during the tape playback process; an optimized playback preampli er is therefore critical to the performance of the medium. Existing playback methods integrate the voltage generated across the reproduce head to obtain a signal directly proportional to the remanent magnetic ux of the tape. An alternate playback method proposes the use of a transresistance ampli er to convert ux-proportional reproduce head current directly to voltage. This eliminates the need for voltage integration and minimizes the amount of equalization performed upon playback. Circuit size and complexity are likewise reduced. A practical transresistance playback preampli er is designed and its performance is evaluated against selected integrating playback preampli ers. SPICE simulation veri es that the proposed design o ers a signi cant reduction in harmonic distortion, as well as improved transient response, magnitude response, and phase margin.