The invention discloses a blood
oxygen saturation measuring device and a measuring method. The measuring device is characterized in that a
microprocessor outputs square
waves at different frequencies and in twice rate relationship, the square
waves drive at least two kinds of light emitting diodes, light emitted by the light emitting diodes is received by a photosensor after passing through a finger to be measured, the light is converted into
voltage signals by the photosensor, the
voltage signals are converted into preset amplitude
voltage signals through a current / voltage conversation
amplifier, an
analog to digital converter converts the preset amplitude voltage signals into digital signals, the
microprocessor processes the digital signals, and the blood
oxygen saturation is obtained. The measuring method comprises the steps that: the
microprocessor carries out separation
processing on the digital signals, photoelectric volume pulse
waves are obtained, and the
background light interference is eliminated; a valley value and a
peak value are obtained according to the photoelectric volume pulse waves; the valley value and the
peak value are calculated to obtain a Q value; and the blood
oxygen saturation is calculated through the Q value, and the blood
oxygen saturation is obtained.
Square wave frequency division modulation and
digital demodulation are adopted, and the blood
oxygen saturation measuring device and the measuring method have the characteristics that the measurement is accurate, the circuit is simple, and the cost is low.