Carl D Andren

US Patent:

6603801, Aug 5, 2003

Filed:

Jan 14, 1999

Appl. No.:

09/231228

Inventors:

Carl Andren - Indialantic FL
Mark A. Webster - Palm Bay FL

Assignee:

Intersil Americas Inc. - Milpitas CA

International Classification:

H04B 1500

US Classification:

375147, 375130

Abstract:

A method and spread spectrum transceiver for demodulating a spread spectrum signal is disclosed. A spread spectrum phase shift keyed (PSK) modulated information signal is received within a demodulator of a spread spectrum receiver on a signal channel. The information signal includes a sequence of data symbols formed from a plurality of high rate mode chips. A precursor portion of the signal channel is Viterbi detected. A multi-state trellis is formed having a predetermined number of states. A post-cursor portion of the signal channel is feedback equalized with a finite impulse response filter having feedback taps operatively connected to a chip detection circuit that tracks high rate mode chips and a carrier loop circuit for phase and frequency tracking. The information signal is despread within a spread spectrum code function correlator.

US Patent:

6678310, Jan 13, 2004

Filed:

Jan 14, 1999

Appl. No.:

09/231184

Inventors:

Carl Andren - Indialantic FL
Mark A. Webster - Palm Bay FL

Assignee:

Intersil Americas Inc - Milpitas CA

International Classification:

H04B 169

US Classification:

375147

Abstract:

A demodulator used in a base band processor of the spread spectrum radio transceiver includes a demodulator circuit for spread spectrum phase shift keying (PSK) demodulating an information signal received from a radio circuit. The information signal includes data symbols formed from a plurality of high rate mode chips forming a spread spectrum information signal. At least one predetermined code function correlator is in line with a signal input for decoding the information signal according to a predetermined code. A carrier loop circuit allows phase and frequency tracking of the information signal and a chip decision circuit is operative with the carrier loop circuit for tracking high rate mode chips. A decision feedback equalizer formed from a feedback finite impulse response filter is operative with the chip decision circuit and the carrier loop circuit. It has a plurality of feedback taps.

US Patent:

6690715, Feb 10, 2004

Filed:

Mar 30, 2001

Appl. No.:

09/823845

Inventors:

Mark A. Webster - Indian Harbour Beach FL
George R. Nelson - Merritt Island FL
Karen W. Halford - Palm Bay FL
Carl F. Andren - Indialantic FL

Assignee:

Intersil Americas Inc. - Milpitas CA

International Classification:

H04J 13104

US Classification:

375148, 375150, 375152

Abstract:

The performance of a RAKE receiver for indoor multipath WLAN applications on direct sequence spread spectrum signals having relatively short codeword lengths is enhanced by embedding a decision feedback equalizer structure in the signal processing path through the receivers channel matched filter and codeword correlator. The decision feedback equalizer serves to cancel both inter-codeword interference (ISI) or âbleed-overâ between codewords, and intra-codeword chip interference (ICI) or smearing of the energy within the chips of a respective codeword.

US Patent:

7212512, May 1, 2007

Filed:

Apr 2, 2002

Appl. No.:

10/113743

Inventors:

L. Victor Lucas - Seattle WA, US
Carl F. Andren - Indialantic FL, US

Assignee:

Conexant, Inc. - Red Bank NJ

International Classification:

H04Q 7/24

US Classification:

370338, 370350

Abstract:

A wireless transceiver including an oscillator, a radio, a baseband processor and MAC device that performs apiori frequency offset correction. The radio converts between RF signals and baseband signals. The baseband processor includes a frequency correction loop, an inverter and a combiner. The frequency correction loop generates a frequency offset signal based on a frequency difference between an oscillator reference frequency and frequency of a received signal. The inverter inverts the frequency offset signal and the combiner adjusts frequency of a transmit signal by the inverted frequency offset signal. The MAC processes received packets, identifies packets received from an AP, provides packets to the baseband processor for transmission, and controls the baseband processor to adjust transmit signals to a frequency of the AP. The baseband processor may include a memory or filter to store or update frequency offset values.

US Patent:

RE40231, Apr 8, 2008

Filed:

Nov 9, 2001

Appl. No.:

10/005483

Inventors:

James Leroy Snell - Palm Bay FL, US
Carl F. Andren - Indialantic FL, US
Leonard Victor Lucas - Seattle WA, US

Assignee:

Conexant, Inc. - Red Bank NJ

International Classification:

H04B 1/69
H04B 1/707

US Classification:

375130, 375142, 375146, 375150, 370342, 370441, 370479

Abstract:

A spread spectrum radio transceiver includes a high data rate baseband processor and a radio circuit connected thereto. The baseband processor preferably includes a modulator for spread spectrum phase shift keying (PSK) modulating information for transmission via the radio circuit. The modulator may include at least one modified Walsh code function encoder for encoding information according to a modified Walsh code for substantially reducing an average DC signal component to thereby enhance overall system performance when AC-coupling the received signal through at least one analog-to-digital converter to the demodulator. The demodulator is for spread spectrum PSK demodulating information received from the radio circuit. The modulator and demodulator are each preferably operable in one of a bi-phase PSK (BPSK) mode at a first data rate and a quadrature PSK (QPSK) mode at a second data rate. These formats may also be switched on-the-fly in the demodulator.

US Patent:

20040010746, Jan 15, 2004

Filed:

Jul 10, 2002

Appl. No.:

10/192037

Inventors:

L. Lucas - Seattle WA, US
Carl Andren - Indialantic FL, US
Perry Frogge - Palm Bay FL, US

International Classification:

H03M013/00

US Classification:

714/781000

Abstract:

An FEC scheme for wireless receivers including a symbol detector, a symbol selector, CRC logic and output logic. The detector correlates each digital group of the packet with a symbol family and provides possible symbols and corresponding correlation factors. The selector selects several possible symbols for each digital group having the highest correlation factors. The CRC logic calculates possible CRC values for the packet using combinations of the selected symbols. The output logic evaluates the possible CRC values to determine whether there is a correct symbol combination. The system may include logic that determines a symbol quality (SQ) metric for each digital group based on a difference between the two highest correlation factors. The system may include a rank value filter that selects a predetermined number of second choice symbols based on the SQ metrics. The CRC logic calculates the CRC values using combinations of first and second choice symbols.

US Patent:

58839216, Mar 16, 1999

Filed:

Jul 31, 1995

Appl. No.:

8/509587

Inventors:

Carl Frank Andren - Indialantic FL
Leonard Victor Lucas - Palm Bay FL
John Christ Fakatselis - Palm Bay FL
Jim Snell - Palm Bay FL

Assignee:

Harris Corporation - Melbourne FL

International Classification:

H04B 708
H04L 106
H04K 100

US Classification:

375208

Abstract:

A digital data radio receiver and method evaluates a data signal preamble received on an antenna to determine whether the antenna should receive the data signal following the preamble. The receiver determines frequency offsets from a desired frequency for each symbol in a block of symbols in the preamble, determines the variance of the frequency offsets, determines the average magnitude of the symbols in the block of symbols, where the determination of average magnitude may be performed in parallel with the determination of variance of the frequency offsets, and evaluates the variance and the average magnitude for the block of symbols to determine whether the preamble is actually noise and to assess reception quality at the antenna. In a two antenna diversity receiver system, these steps may be performed first on a block of symbols received at one antenna and then performed on the next block of symbols received at another antenna. This provides two evaluations that may be compared to select the antenna with the best reception.

US Patent:

47078391, Nov 17, 1987

Filed:

Sep 26, 1983

Appl. No.:

6/535923

Inventors:

Carl F. Andren - Indialantic FL
David A. Olaker - Palm Bay FL

Assignee:

Harris Corporation - Melbourne FL

International Classification:

H04K 102

US Classification:

375 1

Abstract:

In a spread spectrum communications system employing cyclic code shift keying as its primary modulation, the transmission waveform is spread for transmission security by modulo-2 adding a pseudo-noise sequence to the CCSK data symbols prior to phase modulating onto a carrier signal for transmission. If the transmission modulation is minimum shift keying (MSK) the two components of the data stream are applied to the carrier with a differential encoding step implicit in the modulation scheme. This differential encoding characteristic makes stripping of the PN spread function prior to CCSK demodulation difficult at the receiving end. In order to demodulate this waveform in an optimum manner, an array correlator, the adjacent correlator stages of which have one chip relative time displacements of their CCSK reference waveform, is employed. In effect the array correlator becomes a parallel array of matched filters matched to each cyclic shift of the incoming waveform. By modulo-2 addition of the PN spreading waveform with the time displaced CCSK reference waveform in each stage of the correlator, the correlator can be made to match all versions of the spread symbol being received.