发明名称 |
Spread spectrum transmitter and communications system using multiple spreading codes |
摘要 |
A spread spectrum transmitter for generating a plurality of spread spectrum codes comprises a shift register having a plurality of stages, with a plurality of tap sets connected to selected ones of said stages. Each tap set defines a different spread spectrum code, which may be maximal or non-maximal. Outputs from the tap sets are combined using exclusive-OR gates and fed back to through a table of logic gates to the input of the shift register. A serial data register is loaded from a data stream and clocked periodically into a parallel data register. The parallel data register corresponds to a data symbol and is connected to the table, whereby one of the spread spectrum codes at a time is selected. A code portion of the spread spectrum code up to a designated length is generated for each data symbol. More than one code portion may be simultaneously sent using offset quadrature phase shift keying. A receiver may detect the code portion or code portions sent by delaying the received signal and combining it with a plurality of delayed versions thereof, the delay period for each delayed version corresponding to the tap locations in the tap set of the transmitter shift register.
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申请公布号 |
US5790591(A) |
申请公布日期 |
1998.08.04 |
申请号 |
US19950432907 |
申请日期 |
1995.05.01 |
申请人 |
OMNIPOINT CORPORATION |
发明人 |
GOLD, ROBERT;DIXON, ROBERT C. |
分类号 |
H04J14/00;H04L7/04;(IPC1-7):H04B1/707;H04K1/00 |
主分类号 |
H04J14/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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