Radio communications system using spread spectrum process

摘要

The system expands data sequences (UD1-UDN) of numerous communications signals with different orthogonal code sequences (W1-WN). The data sequences are then multiplied by a pseudo-noise sequence (PN). After filtering using a FIR filter, the sequences are supplied to a multistage quadrature modulator as base band signals (iQ). The parallel bit streams (D1.1-D1.N; D1a-DMQ), obtained by the multiplication, are fed to a mapping memory, storing an allocation sign, determined by the modulation type. I and Q values allocated to the bit of the parallel bit stream read-in at uniform clock are read-out of the memory. The I and Q values are filtered in the FIR filter and supplied to the quadrature modulator as base band signals.