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:
Feb. 19, 1991
Filed:
Nov. 30, 1989
Petre Popescu, Kirkland, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A second order active filter comprises an input terminal, an output terminal, and a common terminal, a capacitive T-network comprising three capacitors and, in parallel therewith, a resistive T-network comprising three resistors, the terminals of the T-networks being connected respectively via a first amplifier to the output terminal, via a buffer to the input terminal, and to the common terminal, a potential divider between the output and common terminals, and a second amplifier having an input coupled to a tapping point of the potential divider and an output coupled via a resistor to the central junction of the capacitive T-network and via a capacitor to the central junction of the resistive T-network. In different configurations of the filter, the component coupled to the common terminal may be omitted from one of the T-networks, or from both of the networks with another potential divider coupled between the input and common terminals and a third amplifier coupling its tapping point to one of the networks.