FINITE IMPULSE RESPONSE FILTER IN MODULATOR OF COMMUNICATION SYSTEM

摘要

PURPOSE: A finite impulse response filter in a modulator of a communication system is provided to reduce a tap number of the finite impulse response filter from 48 taps to 12 taps by removing a tap in which zero-padding data is multiplied. CONSTITUTION: A finite impulse response filter in a modulator of a communication system comprises first to twelfth multiplexers(11-1 to 11-12) each of which receives four corresponding filter coefficients to output the received filter coefficients sequentially according to an operation frequency of four times a chip rate. Each of first to twelfth multiplication parts(12-1 to 12-12) multiplies a filter coefficient sequentially outputted from a corresponding multiplexer and data inputted to the filter. Each of first to twelfth multiplication parts(13-1 to 13-12) sequentially adds an output of a corresponding multiplication part. First to eleventh shift registers(14-1 to 14-11) shift outputs of corresponding adders(13-2 to 13-12) so that all data of the adders(13-1 to 13-12) are added at the adder(13-1).