Motorola Corporation

Other

Robert K Schweickert

Clinton C Powell, Ii

Mahibur Rahman

Christopher T Thomas

John Richard Oakley

David L Brown

James G Mittel

Chun-Ye Susan Chang

David F Brown

A symbol independent automatic frequency controller ( ) includes a symbol correlator ( ) for receiving a complex digital signal generated within a selective call receiver wherein the symbol correlator provides a real signal ( ), an imaginary signal ( ), and a magnitude signal ( ), a discriminator ( ) coupled to the symbol correlator for receiving and processing the real signal and the imaginary signal to provide a frequency error signal, a low pass filter ( ) and comparison element ( ) for filtering the magnitude signal and comparing the magnitude signal to a predetermined lock threshold signal that controls the bandwidth of the symbol correlator in the event the magnitude signal exceeds the lock threshold signal, and a feedback loop providing the imaginary signal ( ) to an accumulator ( ) and back to the symbol correlator wherein the accumulator provides the symbol correlator with an apriori-symbol phase feedback ( ).

Method and apparatus for symbol independent discriminator correlator automatic frequency control

A DC offset correction circuit ( ) provides DC offset correction within a receiver ( ) for receiving and processing a radio frequency signal ( ) within a radio communication system ( ). The DC offset correction circuit ( ) includes a feedback loop ( ) for shifting a digital signal ( ) by a programmable amount; and a coarse DC offset correction path ( ) coupled to the feedback loop ( ) for performing coarse DC offset correction.

DC offset correction scheme for wireless receivers

A full serial implementation of a M-level correlation based demodulator ( ) includes a two's complement, pass-through, zero-out complex conjugate multiplier element ( ), a boxcar filter ( ) coupled to the multiplier element, a complex magnitude approximater element ( ) coupled to the boxcar filter and a maximum value and index holding element ( ). The multiplier element reuses common products along an M-level of cross-correlation to reduce multiplication functions at a rate 2 times M faster than a sampling rate at an input of the demodulator.

Method and apparatus for efficient correlation detection

A circuit (12) for symbol decision directed feedback synchronization includes a current synchonization clock (45) that provides an initial sampling point and selects a detector corresponding to a current symbol decision. The circuit further includes a plurality of detectors (31, 32, 33, and 34) including the detector corresponding to the current symbol decision, a buffer (736) for storing the output of the detector corresponding to the current symbol decision and a processor (300) for seeking within a predetermined window about the initial sampling point for an optimum phase value to provide an adjustment signal which is used by the processor to adjust a subsequent symbol's sychronization clock to provide an optimal sampling point.

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Jupiter, FL, United States of America

Robert K Schweickert