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:
Apr. 09, 1991
Filed:
Dec. 14, 1989
Petre Popescu, Kirkland, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A family of second order active filters is described. A general form of the filter comprises an input terminal, an output terminal, and a common terminal, a first reactance and a resistance coupled in series between the input and common terminals, a first emplifier coupled from a connection point between the first reactance and the resistance to the output terminal, a first potential divider between the input terminal and one of the output and common terminals, a second amplifier coupled from a tapping point of the first potential divider via a second reactance to the connection point, a second potential divider between the output terminal and the common terminal, and a third amplifier coupled from a tapping point of the second potential divider via a third reactance to the connection point, at least one of the reactances being inductive and at least one other being capactive. Different configurations are described for low-pass, notch, high-pass, band-pass, and all-pass filters, in some of which the first potential divider and second amplifier and second reactance, or the second potential divider and third amplifier and third reactance, are omitted.