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:
Nov. 07, 2006
Filed:
Dec. 22, 2000
Michael Joseph Mclaughlin, Dublin, IE;
Michael Joseph McLaughlin, Dublin, IE;
Inter-Tel, Inc., Tempe, AZ (US);
Abstract
A precoding circuit for minimizing distortion of an input signal in a communication channel having a compound transfer function in the Z-Domain: H(z)=(+a.z+a.z+a.z+ . . . +a.z)/(+b.z+b.z+b.z+ . . . +b.z). A feedback circuit comprises a first FIR filter and a transfer function corresponding to the inverse of a feedforward part of a transfer function of the communication channel. A feedforward circuit comprises a second FIR filter and a transfer function corresponding to the inverse of a feedback part of a transfer function of the communication channel. A first subtracting circuit subtracts a feedback signal of the feedback circuit from a feedforward signal of the feedforward circuit and outputs a difference signal which is added to a transmit end signal by a first adding circuit. The difference signal is also added to the input signal by a second adding circuit, the output from the second adding circuit is fed to a quantizing circuit which outputs a value kM which is subtracted from the input signal by a second subtracting circuit.