  The sensitivity of radio astronomical stations is often limited by man-made
radio frequency interference (RFI) due to a variety of terrestrial activities.
An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing
is proposed here for the Westerbork Synthesis Radio Telescope based on a
powerful field programmable gate array processor. In this system the radio
astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine
back-end correlation processing takes place. The high temporal and frequency
resolution of RFIMS allows the detection and excision of RFI better than do
standard radio telescope back-end configurations.
