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. 17, 1990
Filed:
Nov. 23, 1988
Kiyoh Takahashi, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A terminal impedance setting circuit in a 2- to 4-wire converting circuit allows the characteristic impedance to be changed with accuracy while enhancing a miniaturization of the converting circuit. The impedance setting circuit has a first amplifier for amplifying signals that are incoming over a send pair of a four wire line and are destined for a two wire trunk line. A second amplifier amplifies signals that are incoming over the two wire trunk line and are destined for a receive pair of the four wire line. A resistor network is associated with each of the amplifiers for adjusting the output thereof. A shunt resistance is coupled between an input of the first amplifier and an output of the second amplifier for matching the impedance of the two wire trunk line. A semiconductor switch adjusts the resistances of the resistor networks and the shunt resistance in response to an external command.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile