#$%^&*AU2008201890B220121025.pdf#####ABSTRACT A method for monitoring an electrocardiogram (ECG) signal of a subject, includes digitally sampling an average signal from at least a first ECG electrode, determining an average interference frequency, and digitally sampling and buffering 5 a raw ECG signal from at least a second ECG electrode. The method further includes: filtering the raw ECG signal to generate a residual signal； calculating, based on the residual signal, a first amplitude and a first phase shift of a primary interference signal at the average interference frequency and a second amplitude and a second phase shift of one or more harmonic interference signals at respective 10 multiples of the average interference frequency； and digitally subtracting the primary interference signal and the one or more harmonic interference signals from the raw ECG signal so as to generate and output a clean ECG signal. 30/04/08,kn 17253 specification.]63/3 FIG. 3A ECG SIGNAL FIG. 3B RESIDUAL SIGNAL FIG. 3C INTERFERENCE FILTER FIG. 3D FILTERD ECG
