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:
Sep. 19, 1995
Filed:
Oct. 22, 1993
Arthur J Lim, Menlo Park, CA (US);
Lumisys, Inc., Sunnyvale, CA (US);
Abstract
A wideband amplifier which employs a plurality of cascaded logarithmic amplifier stages under the control of a digital signal processor which nulls offset voltages. In one aspect of the invention, the digital signal processor controls switches, one switch associated with each amplifier stage for determining an appropriate offset voltage and producing a counterbalancing signal. In another aspect of the invention the amplifier includes two potentiometers or variable signal devices which can set the overall input signal level and set the ratio of maximum to minimum of the input signal level, respectively, to desired levels. In a third aspect of the invention, a lookup table is associated with the digital signal processor for storing correction factors to be applied to digitized values in order to produce a final result which is corrected for variations in the amplifier characteristic from true logarithmic.