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. 06, 1996
Filed:
Feb. 16, 1995
James D English, Aloha, OR (US);
Seiko Communication Systems, Inc., Beaverton, OR (US);
Abstract
A subcarrier signal generator includes a finite impulse response (FIR) filter responsive to selected FIR coefficients. A first set of FIR coefficients represents an ideal subcarrier shape and center frequency. A calibration step monitors the resulting subcarrier signal and produces a new set of FIR coefficients corresponding generally to the ideal subcarrier signal shape and center frequency, but predistorted according to the compliment of error detected in the actual subcarrier signal. By then loading the new set of FIR coefficients and operating the subcarrier generator, frequency-dependent distortions in the output stage of the subcarrier generator cancel predistortion reflected in the new FIR coefficients. As a result, a high quality subcarrier signal results without use of expensive output stage devices in the subcarrier signal generator.