System and method for suppression of RFI interference

dcm dcm A1sub dA1sub A2A2 A2 A2A2 d dA system and method for suppressing RFI receives a differential input signal V, and a signal Vwhich varies with the common mode component of V. Vis phase-shifted and then amplified with a programmable gain G to produce an output V. A subtractor produces an output Vwhich varies with V−V. Vis amplified with a programmable gain G to produce an output V. An analog input signal processing circuit receives Vat an input which has an associated maximum dynamic range. A processor adjusts G such that Vcovers the maximum dynamic range, adjusts the phase shift and G to minimize V, and adjusts G to increase Vsuch that it again covers the maximum dynamic range. The RFI in Vis substantially subtracted out, thereby enabling the full dynamic range of the analog input signal processing circuit to be employed in receiving V.