Patent ID: 7569821
Filing Date: 2009-08-04
Classification: A61B,G01N,H04B,H04J

Abstract:
1. A biological information measuring apparatus comprising a light emission section and a light detection section, wherein the light emission section includes: base-band-signal output means for generating and outputting a predetermined base band signal; spread-code-sequence generation means for generating a spread code sequence at a first frequency, the spread code sequence being used for modulating the base band signal through spread spectrum modulation; first modulation means for spectrum-spreading the base band signal by using the spread code sequence generated by the spread-code-sequence generation means, to thereby output a primary modulated signal; second modulation means for modulating the primary modulated signal output from the first modulation means by using a clock signal of a second frequency two times the first frequency, to thereby output a secondary modulated signal; and light generation means having at least one light source and emitting an near-infrared light beam into a living organism, the near-infrared light beam being generated on the basis of the secondary modulated signal output from the second modulation means and having a specific wavelength, and the light detection section includes: light receiving means for receiving the near-infrared light beam having been emitted from the light emission section and propagated through the living organism, converting the received near-infrared light beam to an electrical detection signal, and outputting the electrical detection signal; signal component removal means for removing from the electrical detection signal a DC component, signal components of frequencies near DC, and signal components of frequencies equal to or higher than the second frequency, and outputting the electrical detection signal; signal conversion means for converting the electrical detection signal output from the signal component removal means to a digital signal by using a clock signal of a third frequency two times the second frequency, the clock signal of the third frequency being supplied in consideration of a delay of the near-infrared light beam produced due to propagation of the near-infrared light beam through the living organism; first demodulation means for demodulating the digital signal by using the clock signal of the second frequency, to thereby output a primary demodulated signal, the clock signal of the second frequency being supplied in consideration of the delay of the near-infrared light beam produced due to propagation of the near-infrared light beam through the living organism; second demodulation means for spectrum-despreading the primary demodulated signal by using the spread code sequence to thereby output a secondary demodulated signal, the spread code sequence being supplied in consideration of the delay of the near-infrared light beam produced due to propagation of the near-infrared light beam through the living organism; and biological-information-signal output means for outputting a biological information signal representing biological information associated with the metabolism of the living organism by using the secondary demodulated signal output from the second demodulation means.