To prevent mutual interferences among channels with a simple circuit structure by using a specific an approximate synchronous CDMA code as a spread spectrum processing code, when a sending part side performs spread spectrum processing and sends a result.
A sending part generates an approximate synchronous CDMA code, which consists of a real part and a virtual part and multiplies the real part by a signal. On the other hand, it generates an orthogonal element of a carrier signal and multiplies the virtual part of the approximate synchronous CDMA code by the orthogonal component of a carrier signal. It adds an output of a multiplier for the real part with an output of a multiplier for the virtual part and sends them. Here, when a cyclic matrix (represented by an expression I) of cycle series of a cycle N is A and B is a diagonal matrix as codes for spread spectrum processing, A=F-1BF on the condition that F takes a series where a self correlation function becomes zero for all the terms, excepts for a multiple of the cycle as an orthogonal series under the condition where a DFT matrix is established. An approximate synchronous CDMA code is used in an expression II under the presence of B, D.
KAMATA MUTO
FUJIMOTO YUUKI
