| abstract |
The optical sensor device (1) comprises a light emitter (2) intermittently flashing two wavelengths of light towards a living body (B) at a predetermined frequency (f), and a photoreceiver (7) receiving the light from the living body (B). The photoreceptor (7) outputs first and second detection signals (S1), (S2) corresponding to each wavelength. From the first and second detection signals (S1), (S2), a filter circuit (9) extracts modulated signals (S1m), (S2m), which are amplitude-modulated signals at the predetermined frequency (f). The modulated signals (S1m), (S2m) are amplified by a subsequent-stage amplifier (10) to modulated signals (S1M), (S2M), converted to digital signals by an AD converter (14), and inputted to an arithmetic processing unit (15). The arithmetic processing unit (15) uses the digitalised modulated signals (S1M), (S2M) to calculate the direct current component (S1d), (S2d) and the alternating current component (S1a), (S2a) of the first and second detection signals (S1), (S2). |