Finite impulse response filter for multi-code CDMA signals

This invention relates generally to the field of wireless communications systems and more particularly, to apparatus and methods for modulating and filtering the signal in a mobile transmitter in a TR45.5 ITU-R code division multiple access (CDMA) system. Disclosed is a method and apparatus for filtering a plurality of CDMA signals. The signals are processed by a plurality of modulators. More specifically, the plurality of modulators performs orthogonal code and pseudonoise (PN) spreading on the plurality of CDMA signals, where the spreading produces a 1-bit in-phase (I) data stream and a 1-bit (Q) data stream. These streams are also processed by a plurality of filter the 1-bit I and 1-bit Q data streams and produce at least one n-bit wide I data stream and at least one n-bit wide Q data stream, where n is an integer of at least one.The invention further includes a central processing unit for generating at least one gain factor. A processor is coupled to the filters and the central processing unit. The processor performs per channel power control and combining of the n-bit wide I data and n-bit wide Q data streams into one I stream and one Q stream using the gain factor generated by the central processing unit. A gain amplifier is also electrically coupled to the processor. The stream are sent to the gain amplifier for amplifying the output of the processor using the gain factor.