The Giant Metrewave Radio Telescope (GMRT) is being upgraded to increase the
receiver sensitivity. This makes the receiver more susceptible to man-made
Radio Frequency Interference (RFI). To improve the receiver performance in
presence of RFI, real-time RFI excision (filtering) is incorporated in the GMRT
wideband backend (GWB). The RFI filtering system is implemented on FPGA and
CPU-GPU platforms to detect and remove broadband and narrowband RFI. The RFI is
detected using a threshold-based technique where the threshold is computed
using Median Absolute Deviation (MAD) estimator. The filtering is carried out
by replacing the RFI samples by either noise samples or constant value or
threshold. This paper describes the status of the real-time broadband RFI
excision system in the wideband receiver chain of the upgraded GMRT (uGMRT).
The test methodology for carrying out various tests to demonstrate the
performance of broadband RFI excision at the system level and on radio
astronomical imaging experiments are also described.Comment: 7 pages, 7 figure
