Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2005-03-15
2005-03-15
Tran, Khai (Department: 2637)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S350000, C708S404000
Reexamination Certificate
active
06868114
ABSTRACT:
In a frequency-domain excision system for a wide band receiver, a window function is applied to blocks of received signal samples and a transform function is applied to the windowed blocks. Each block of frequency-domain coefficients from the transform function is morphologically filtered to generate a threshold function representing an estimate of the spectrum of the desired wide band signal, and a non-linear gain function is applied to the coefficients. The gain function has a fixed-gain region for input values less than a threshold value from the threshold function, an excision region for input values greater than a multiple of the threshold value, and a soft limiting region between the fixed-gain region and the excision region. The inverse transform is performed on the excised blocks of coefficients, and an overlap-eliminating central portion of the inverse of the window function is applied to the resulting blocks of signal samples.
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Bially Theodore
McKenzie Paul F.
The Titan Corporation
Tran Khai
Weingarten Schurgin, Gagnebin & Lebovici LLP
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