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:
Aug. 20, 2002
Filed:
Apr. 04, 2000
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A GFSK modulator suitable for use in an RF communication system comprising a modular subsystem and a baseband processor subsystem which is implemented digitally. The baseband processor subsystem comprises a Gaussian filter, phase accumulator and cosine and sine look up tables. The baseband processor functions to convert an input data sequence into I and Q output signals. The I and Q signals are subsequently modulated by a quadrature modulator to yield a GFSK modulated signal which can then be amplified and placed into the channel. The response of the Gaussian filter is pre-calculated for all possible combinations of the input data and the results are quantized and stored in a look up table. The quantized phase results (either magnitude or differences), generated in response to the input data, are accumulated digitally and converted to I and Q signals. The modulator may be implemented using three look up tables: two of which are for storing cosine and sine values and the third is used to store the pre-calculated quantized phase results (either absolute magnitudes or differences). The size of the three look up tables may be reduced by taking advantage of the symmetry properties of the Gaussian filter response and the cosine and sine functions.