Patent ID: 8472514

Claim:
An apparatus to perform adaptive spectral enhancement and harmonic separation, the apparatus comprising: a spectral enhancement and harmonic notching circuit comprising a coefficient input line, a signal input line, a first output port and a second output port; wherein the spectral enhancement and harmonic notching circuit receives on the signal input line, an input signal comprising electromagnetic interference (EMI) at an unknown frequency; wherein the spectral enhancement and harmonic notching circuit comprises a spectral enhancement circuit to supply on the first output port, a fundamental-enhanced signal or complement thereof generated by enhancing the input signal at least at a current estimate of the unknown frequency, the current estimate being identified from a coefficient signal on the coefficient input line; wherein the spectral enhancement and harmonic notching circuit further comprises a cascade of notching circuits to supply on the second output port, a cascaded-harmonic-notched signal generated by notching the input signal at the current estimate followed by notching at a harmonic of the current estimate; an adaptation circuit comprising an initialization line, an input line, an error line, and a coefficient output port; wherein the input line of the adaptation circuit is coupled to the first output port, of the spectral enhancing and harmonic notching circuit; wherein the error line of the adaptation circuit is coupled to the second output port, of the spectral enhancing and harmonic notching circuit; wherein the adaptation circuit generates the coefficient signal on the coefficient output port, using at least: (i) the fundamental-enhanced signal or complement thereof received on the input line of the adaptation circuit, (ii) the cascaded-harmonic-notched signal received on the error line, and (iii) an initial estimate of the unknown frequency received on the initialization line; wherein the coefficient output port of the adaptation circuit is coupled to the coefficient input line of the spectral enhancement and notching circuit, to adaptively change the current estimate over time.