Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2005-05-24
2009-10-20
Ha, Dac V (Department: 2611)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S152000, C375S343000, C370S320000, C370S335000, C370S342000, C370S441000, C708S422000, C708S425000
Reexamination Certificate
active
07606292
ABSTRACT:
A parallel correlator and method includes temporarily storing in a series of P sequence registers, each of length R1, serial bit-sequences of a code of length N=P*R1. In a first-level of processing, certain unique bit sequences are inverted to reduce the number of unique bit sequences by half. Identical bit-sequences are then combined and temporarily stored in a first-level sub-accumulation register. Alternatively, bit sequences differing by only one bit may be combined in a common first-level sub-accumulation register. Further levels of similar processing may be imposed, where each subsequent level taps and inverts only a portion of the bits in the above level of processing, thereby reducing the number of unique bit sequences. Finally, all negative energy is combined in one register position, inverted, and added to all positive energy in the other register positions. When the spreading code was aligned among the series of sequence registers, the energy is added coherently and an energy peak is output, indicating alignment of the spreading code in the sequence registers.
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Ertel Richard B.
Giallorenzi Thomas R.
Griffin Dan M.
Hall Eric K.
Harris Johnny M.
Ha Dac V
Harrington & Smith PC
L-3 Communications Corporation
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