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Patent Searching and Data


Title:
SPREAD SPECTRUM POLYPHASE MODULATION/DEMODULATION METHOD
Document Type and Number:
Japanese Patent JP3268308
Kind Code:
B2
Abstract:

PURPOSE: To solve a problem of making information hard to discriminate due to an exponential increase of code points to decrease distance between each other of code points by increasing the number of information bits in polyphase modulation.
CONSTITUTION: Serial transmission data SD (...101...) is converted to parallel data by a serial-parallel converter 1, and three ((n) in general) parallel bits 1, 0 and 1 are inputted to information spreader 2, 3 and 4, respectively, and the information (spectrum) is spread by using spread codes A, B and C. Spread data (a), (b) and (c) are added by an adder 5 at each bit, ad each bit is changed to multi-valued data (s) with four values. The information diffusers 2, 3 and 4 output the spread codes as they are when input data is 1, while outputs then by inverting 0, 1 of each bit when it is 0. The multi-valued data (s) is inputted to a modulator 6, each bit converted into parallel data, and the phase shift quantity of a carrier are set at 0, π/2, π, -θ/2 corresponding to the values 0, 1, 2 and 3 of each bit of the data (s). On the demodulation side, multi-valued data s' is obtained through plane detection, the correlation of the data s' with each spread code is detected, and transmission data 1, 0 and 1 are restored.


Inventors:
Norihiro Ando
Application Number:
JP28668293A
Publication Date:
March 25, 2002
Filing Date:
November 16, 1993
Export Citation:
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Assignee:
Japan Aviation Electronics Industry Co., Ltd.
International Classes:
H04B1/707; H04J13/16; (IPC1-7): H04B1/707
Domestic Patent References:
JP5252141A
JP5130068A
Other References:
渡辺君夫他,多数決情報伝送による符号分割多重通信方式,電子情報通信学会技術研究報告SST92−82,p.51−56
Attorney, Agent or Firm:
Kusano Taku (1 person outside)