| 摘要 |
PROBLEM TO BE SOLVED: To provide a filtering device that keeps a component of a desired signal of a low band unattenuated although attenuating a direct current.SOLUTION: The filtering device includes: a bandpass filter 11 for extracting a predetermined band signal B from a full band signal A; a difference operation section 13 for computing a difference between the full band signal and the predetermined band signal to generate a low frequency signal C including a DC component; a first PDF processing section 15 for generating a first PDF signal D of the low frequency signal; a phase shifter 16 for shifting the phase of the low frequency signal by a predetermined phase to generate a low frequency phase-shifted signal E from the low frequency signal; a second PDF processing section 17 for generating a second PDF signal F of the low frequency phase-shifted signal; a correlation value calculation section 18 for determining a correlation value between the first PDF signal and the second PDF signal; an estimate value calculation section 19 for estimating the DC component of the low frequency signal on the basis of a maximum value of the correlation value in outputting an estimate value; and a subtracter 21 for subtracting the estimate value from the low frequency signal. |
