Systems, methods, and devices are provided for suppressing cross-talk noise due to capacitive and/or inductive coupling in a medical sensor signal. For example, an embodiment of a patient monitor may include driving circuitry, an amplifier, and transient current discharge circuitry. When the driving circuitry drives an emitter to emit light into a patient, a detector may detect a portion of the light that passes through the patient, generating a detector signal. Cross-talk between the emitter driving signals and the detector signal may generate interference in the form of a transient current in the detector signal. Before the amplifier receives the detector signal, transient current discharge circuitry may discharge the transient current.