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:
Jun. 26, 1979
Filed:
Sep. 30, 1976
Michael F Braitberg, Larkspur, CO (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
A magnetic record reproducing system preamplifier includes an inductive choke in the emitter circuit of a first stage transistor amplifier whereby to provide a frequency responsive variable input impedance whereby to maintain a proper impedance relationship between the inductive transducer and the input impedance of the first stage amplifier. A second stage transistor amplifier is connected to the output of the first stage amplifier in cascode relationship, reducing the effective voltage gain of the first stage to substantially zero. The choke in the input circuit of the first stage amplifier acts as a degenerative feedback at higher frequencies, effectively reducing the bias current through the first stage transistor. The base emitter capacitance of the first stage transistor tends to resonate with the inductance of the transducer. The effective degenerative feedback at that first stage transistor tends to push that resonant frequency beyond the desired or useful frequency band of the system.