A digital intermediate-frequency signal processor and digital filter supporting software-defined radio system and its design

PURPOSE: A digital filter for SDR(Software-Defined Radio) system, an apparatus having the filter and processing digital intermediate frequency band signal and a method thereof are provided to enable hardware devices to share hardware resources with each other by embodying a receiving filter, which can reconfigured with minimum hardware devices, in digital for each communication standard item. CONSTITUTION: A signal received from an antenna(301) is converted into an analog IF signal through an RF signal processor(302). An analog-digital converter(303) converts the analog IF signal into a digital signal and a digital frequency mixer(306) converts the digital signal into a baseband signal. The digital frequency mixer(306) receives an input from a numerically controlled oscillator(307) for calculating a sine function value of digital frequency. A configurable filter building block(309) removes a high band signal from the baseband-converted signal. A configuration processor(308) receives an input from a filter coefficient calculator(305) for transferring a filter coefficient to the configurable filter building block(309). The configuration processor(308) receives an input from an external filter coefficient input unit(304).