Patent ID: 8918444

Claim:
A filter device for filtering an input signal, the input signal comprising a clock signal having a clock frequency, the filter device comprising: a filter that filter the input signal with a first set of filter coefficients to obtain a first filtered signal, and that filters the input signal with a second set of coefficients to obtain a second filtered signal; a frequency domain correlator that correlates a first subset of frequency domain components of the first filtered signal to obtain a first correlation value, and that correlates a second subset of frequency domain components of the second filtered signal to obtain a second correlation value, wherein the first subset of correlated frequency domain components and the second subset of correlated frequency domain components are respectively located within a predetermined range of the correlated signals comprising the clock frequency; and a processor that selects either the first set of filter coefficients or the second set of filter coefficients upon the basis of the first correlation value and the second correlation value for filtering the input signal.