Efficient multichannel filtering for CDMA modems

The present invention provides a multichannel digital filter for filtering a plurality of signals transmitted via a plurality of channels in a code division multiple access (CDMA) communication system, the multichannel digital filter comprising: a plurality of filter inputs, one for each of the plurality of channels; a filter output for generating a single filter output for the plurality of filter inputs from the plurality of channels; a plurality of look-up tables (LUTs), each LUT comprising a plurality of memory addresses, for storing respective ones of precomputed weighted sums for all possible combinations of the plurality of filter inputs, whereby each LUT outputs a weighted sum of the plurality of filter inputs in accordance with the filter inputs from the plurality of channels; and a plurality of registers and a plurality of adders alternately arranged in series, whereby each adder adds outputs of the LUT and the value stored in each register in each operation cycle and each register buffers the output of each adder temporarily until the next operation cycle.