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. 02, 1979
Filed:
May. 04, 1977
Horst Rossbach, Eichenau, DE;
AGFA-Gevaert AG, Leverkusen, DE;
Abstract
A sound recording head includes an induction coil. A feedback resistor is connected in series with the induction coil between the input and output of an operational amplifier to form the feedback branch of the amplifier. A load resistor is connected to the junction between the feedback resistor and the induction coil. An audio-frequency audio signal and also a higher-frequency magnetic biasing signal are applied to the operational amplifier input. The open-loop gain of the operational amplifier is at least one order of magnitude greater than the gain of the amplifier with the aforementioned feedback branch connected thereto. The resistance of the feedback resistor is at least one order of magnitude greater than the impedance of the induction coil at the frequency of the magnetic biasing signal. The resistance of the load resistor is at least one order of magnitude smaller than the impedance of the induction coil at the frequency of the magnetic biasing signal.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile