专利名称：A method and apparatus for spread
spectrum code pulse position modulation
发明人：Israel Bar-David申请号：EP95305906.0申请日：19950823公开号：EP0700170A3公开日：20000329
专利附图：
摘要：In a spread spectrum code pulse position modulated communication systemthe frequency spectrum of a transmitted signal is spread by encoding bits with apredefined spectrum-spreading codeword (420,440) which is in accordance with
regulatory requirements or other standardization decisions. When the predefined spreadspectrum codeword is passed through a filter matched to the characteristics of thecodeword, a peak is detected in the main lobe. A positive main lobe can indicate a binaryvalue of \"0\" and a negative main lobe, associated with the inverse of the predefinedcodeword, can represent a binary value of \"1\". Additional information is conveyed bymodulating the position of the center of the codeword within the symbol duration. In oneembodiment, the position of the center of the codeword is varied (410) among eightpositions. Thus, eight signal states are available, and three additional bits may thereby beconveyed. Two differently and independently time-shifted spread spectrum codewords(420,440) may be modulated (455), each with one of two orthogonal carrier signals, suchas a sine and a cosine wave, thereby conveying a total of eight bits per symbol duration.Here, a symbol duration is the duration of a codeword.
申请人：AT&T Corp.
地址：32 Avenue of the Americas New York, NY 10013-2412 US
国籍：US
代理机构：Buckley, Christopher Simon Thirsk
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