Northrop Grumman Systems Corporation

Northrop Grumman Space & Mission Systems Corporation Space Technology

Ali Robert Golshan

Scott A Cooper

Stuart T Linsky

Christopher W Walker

A decoder of a data signal subjected to phase shifting keying (PSK) modulation uses a plurality of phase locked loops (-to-) having an inner decoder for short block codes, at least one of which is adapted to apply excess processing power to process a selected burst of the data signal, such as processing the burst with multiple initial phase/frequency error estimates. A selection circuit identifies the burst and supplies to said one of said plurality of phase-locked loops (-to-) for re-processing the bust with excess processing power. An outer Reed-Solomon block decoder (319) may be used to correct errors in the codewords from the phase locked loops and may be used in the selection of the burst by the selection circuit.

Decision directed phase locked loops (DD-PLL) with excess processing power in digital communication systems

A decision directed phase locked loop (DD-PLL) is efficiently implemented in a communication receiver. The phase locked loop includes an enhanced block decoder inside a phase detector which takes in the baseband complex samples and the current channel phase estimate (or the tracked phase) and generates a feedback phase error term. A loop filter filters the phase error terms and a phase accumulator updates the tracked phase estimate on each iteration of the loop.

Efficient implementation of a decision directed phase locked loop (DD-PLL) for use with short block code in digital communication systems

A demodulator demodulates a modulated signal waveform in a data communication system. A phase tracking loop tracks the phase of said modulated signal waveform and having an inner block decoder configured to decode a set of vector pairs of the modulated signal waveform at a decode rate to generate associated codewords and phase estimates. A group of data symbols consisting of the first data symbols of the modulated signal waveform are run backwards through the phase tracking loop. An outer block decoder receives the associated codewords generated by said inner block decoder and utilizes and corrects only codewords associated with symbols after and including the group of data symbols consisting of the first data symbols of the modulated signal waveform.

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Hawthorne, CA, United States of America

Ali Robert Golshan