Multicode CDMA transmitter with improved signal processing

Abstract

CDMA communication over multiple channels by phase shifting at baseband and then RF modulating without a phase shift. Total number of baseband filters is reduced by summing channel components prior to baseband filtering.

What is claimed is:  
     
         1 . A code division multiple access communication system for processing a communication and transmitting said communication using an RF carrier, comprising: 
 a plurality of individual code channels, each said code channel including part of said communication, said part being processed separately from other parts of said communication, at least one of said individual code channels being transmitted with a phase shift relative to another code channel;    said at least one code channel including: 
 a phase shifting circuit operating to phase shift said signal relative to said another code channel, said phase shifting circuit operating at a baseband frequency to produce a phase shifted signal; and  
 an RF modulator, modulating the phase shifted signal according to the RF carrier to produce a signal at said RF carrier that is phase shifted relative to said another code channel.