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:
Jan. 27, 1981
Filed:
Oct. 15, 1979
Kurt H Mueller, Wallisellen, CH;
Jean J Werner, Eatontown, NJ (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
In a data receiver (40) for a quadrature-amplitude-modulated signal s(t) having symbol interval T, line samples (s.sub.k) are formed at a sampling frequency n/T which is at least equal to the Nyquist frequency. With the sampling being performed at this rate, the functions conventionally provided by individual bandpass filter (12), phase splitter (14) and equalizer (22) circuits are performed by a single transversal filter equalizer (122). Tap coefficients for the transversal filter equalizer are derived in a decision-directed manner. The tendency of the tap coefficient values to drift is suppressed by adding energy to the received signal at frequencies within the band (0-n/2T) Hz at which the received signal has negligible energy.