FIELD: physics.
SUBSTANCE: device includes a light source for emitting light pulses into a living creature tissue, a light sensor, a filter unit for filtering a sensor signal that contains a switchable in-phase low-pass filter to form a common-mode filter signal and a switchable non-phase low-pass filter to form an in-light and the filter unit such that the in-phase filter is turned on only for the second time period, when the light source is turned on and in such a manner that the non-phase filter is turned on during the first and the third time periods, when the light source is turned off. The first and the third time periods provide a locally increased sampling frequency near the second time period such that the non-phase signal of the filter interpolates the interference signal from the ambient light and the common-mode noise of the filter, the unit for subtracting the non-phase signal of the filter from the in-phase signal. The control method is provided by the device.
EFFECT: extending the arsenal of means to measure heart rate.
15 cl, 9 dwg
