Pacific Communication Sciences, Inc.

Rockwell Semiconductor Systems, Inc.

David A Wright

Neal K Riedel

James E Petranovich

Rex L Baker

Terrance R Bourk

The present invention provides methods for combining antenna diversity and gain control in a communications system using a single chain of receiver electronics. A number of input parameters related to various characteristics of a received signal are used to determine the quality of the received signal. The antenna diversity and gain control procedures are enabled or disabled based on the signal quality. The antenna diversity procedure estimates the signal level of the non-operational antenna using an infinite impulse response digital filter. The gain control procedure selects one of three gain paths based on the received signal strength.

Multiple antenna home base for digital cordless telephones

The present invention provides a system and methods for coding and decoding digital data to improve the subjective quality of a voice signal. According to the invention, a sampled voice waveform is compressed by an ADPCM algorithm resulting in a sequence of samples. The sequence of samples are formed into an array and coded into parity bits. Row and column checksums are preferably performed on the parity bits to form row and column vectors. The samples and row and column vectors are transmitted to a receiving unit preferably having a diversity capability. The receiver processes each diversity block by generating row and column vectors from the received samples and comparing the generated row and column vectors to the row and column vectors received. Then based on the comparison, the samples of the best diversity block are used to reconstruct the voice waveform on a sample-by-sample basis.

ADPCM coding and decoding techniques for personal communication systems

Methods and apparatus for digital cordless telephone systems are disclosed for detecting and correcting errors in received signals. Such methods and apparatus include providing a table of predetermined syndromes, wherein each of the predetermined syndromes has an associated error correction pattern. The table is formed by selecting from all possible syndromes that could be predetermined from the segment length of received digital data, those predetermined syndromes having error patterns for correcting a predetermined number of errors within the segment and arranging the predetermined syndromes in the table in accordance with a predetermined order, such as ascending or descending numerical order. Thereafter, a current syndrome is calculated for the received digital data and the predetermined syndrome contained in the table matching the current syndrome is located by using a predetermined search technique. Received digital data is corrected by retrieving the error correction pattern associated with the located predetermined syndrome and correcting the error in the received digital data in response to this error correction pattern.

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Utica, NY, United States of America

David A Wright