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. 25, 2000
Filed:
Jun. 20, 1996
William C Timm, McKinney, TX (US);
Walter Y Chen, Plano, TX (US);
Gene A Frantz, Missouri City, TX (US);
Domingo G Garcia, Plano, TX (US);
Xiaolin Lu, Dallas, TX (US);
Dennis G Mannering, Garland, TX (US);
Michael O Polley, Garland, TX (US);
Terence J Riley, Rockwall, TX (US);
Donald P Shaver, Dallas, TX (US);
Song Wu, Dallas, TX (US);
Alan Gatherer, Richardson, TX (US);
Paul E Schurr, Plano, TX (US);
Douglas B Weiner, The Colony, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A modem communication system with receiving and transmission paths includes a direct equalizer system having an adaptive filter (1532) in the transmission path to compensate for frequency distortion of the communication channel. The transmitter filter coefficients are adapted by a filter coefficient calculator (1528), under control of a data detector (1526) which detects incoming data in the receiving path. A switch (1534) is controlled by status of a transmit output data buffer to multiplex either the training sequence or output data into the transmission path. When the buffer is idle, the training sequence generator (1540) is linked to a digital-to-analog (D/A) converter (1536) and line driver (1538). The receiving path includes an isolation switch (1520), a receiver amplifier (1522) and a slicer (1524). The receiver correlates the received training sequence with a known training sequence and updates the equalizer filter coefficients using an adaptation algorithm, such as a least mean squared algorithm. A first embodiment utilizes a high speed digital programmable filter (1532). Another embodiment utilizes a data buffer (1533) which is periodically filled with data filtered by a digital signal processor (DSP).