1. An apparatus for processing a digital intermediate frequency signal in a software-defined radio system, which is driven by software, the apparatus comprising: a digital frequency mixer for, upon receiving a digitalized intermediate frequency signal, converting the received intermediate frequency signal to a baseband signal; a receiver filter for removing a high-band signal from the converted baseband signal; a receiver filter building block for controlling implementation of the receiver filter to support multiple communication standards; an implementation controller for controlling implementation of the receiver filter building block; and a filter coefficient calculator for receiving information about a specification of the receiver filter from the implementation controller, calculating a coefficient of the receiver filter using the received information, and providing the calculated coefficient of the receiver filter to the implementation controller.