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:
May. 11, 1982
Filed:
Oct. 09, 1979
Pern Shaw, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A subtractor for use in a digital to digital converter has fast response and uses an operational amplifier. The fast response is achieved by varying current flow in associated circuits. An analog input controls current flow through a first portion of the circuitry and a voltage reference controls current flow through a second portion of the circuit. The total current flow through the first and second portions of the circuit is provided by a current source. The analog input is coupled to a first input of the operational amplifier and the voltage reference is coupled to a second input of the operational amplifier. A first logarithmic impedance is coupled between the first input of the operational amplifier and the output of the operational amplifier. A second logarithmic impedance is coupled between the second input of the operational amplifier and a bias voltage. The bias voltage is used to provide a predetermined biased voltage at the output of the operational amplifier.