| 摘要 |
PROBLEM TO BE SOLVED: To extract a desired signal in a very simple constitution and with high reliability by equipping a subtractor for obtaining a difference and a coefficient arithmetic means for determining a constant of an adaptive filter so that the average of square values of differences is small, and outputting the difference as extraction result of a desired component. SOLUTION: A subtractor 11 subtracts an estimated value M(n) from a pulse wave signal x(n). That is, a residual signal e(n) becomes equal to p(n)+m(n)-M (n). A coefficient arithmetic part 10 sequentially calculates such a constant that the square average of residual signal e(n) is minimum on the basis of the past sample, and a calculated constant is set in an adaptive filter 9. A frequency analyzing part 12 conducts high speed Fourier transform processing for a series of residual signals e(n) to obtain the frequency component. A pulse wave extract part 13 extracts a component having the maximum level among the frequency components as a pulse wave component, and a pulse rate arithmetic part 14 computes a pulse rate per one minute according to the frequency value related to the pulse wave component, and a display part 15 displays a computed pulse rate. |
