Operations on a finite field are closed under summations and multiplications thus eliminating errors caused by rounding. This benefit of finite field arithmetic has the potential of improving signal-to-noise ratios for radio frequency interference (RFI) mitigation. We study the impact on performance of the use of finite fields on RFI mitigation algorithms. An implementation on a Field Programable Array (FPGA) is proposed to validate results with respect to traditional fixed-point or floating-point representations.