The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 09, 1979
Filed:
Oct. 01, 1976
Charles E Wright, Escondido, CA (US);
Ward M Calaway, Sierra Madre, CA (US);
Eastman Technology, Inc., Rochester, NY (US);
Abstract
A high Q magnetic playback head applies its developed signal to the input of a voltage mode circuit. To facilitate equalizer design, the head is resistor-damped. While mere resistor damping reduces the Q of the head, it does so at the expense of the signal-to-noise ratio (SNR) of the head-and-amplifier circuit. To maintain SNR substantially without change, the amplifier employs a large resistance to which negative feedback is applied so the resistance appears as an effective resistance equal to its actual value divided by the amplifier gain. The value of this effective resistance is made to equal the magnetic playback head inductive reactance at the point of resonance, thereby reducing the head Q to approximately 1, and equalizer design is made easier.