Texas Instruments Corporation

Haviv Ilan

Eric Baissus

Yaron Kaufmann

Alexander Bronfer

Onn Haran

Eldad Falik

A novel and useful apparatus for and method of clock recovery from a serial data stream. The clock recovery mechanism of the present invention provides accurate and fast timing recovery while operative to filter out the effects of noise. The clock recovery mechanism clocks the received serial data into a shift register of N bits, where N is an even number equal to the oversampling factor of the data signal. A timing correction, generated during learning cycles, is applied during the subsequent correction cycle. The timing is adjusted during correction cycles by preloading the reference counter, from which the sampling clock is produced, such that its cycle is either shortened or extended by M clocks, where M corresponds to the required timing correction.

Apparatus for and method of clock recovery from a serial data stream

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.

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Rosh-Ha′ayin, Israel

Haviv Ilan