Sensor device to mitigate the effects of unwanted signals made in optical measurements of biological properties

A wearable device to determine a biological parameter of a tissue of a person, the wearable device comprising:

• a processing module operatively attached to a display;
• a light emitter operatively connected to the control unit and configured to emit a first light signal and a second light signal towards the tissue, the second light signal is defined as substantially not penetrating the tissue;
• a light detector operatively connected to the control unit and configured to collect a first received signal and a second received signal that are received back from the tissue responsive to the first light signal and the second light signal respectively;
• wherein the processing module converting the first received signal and the second received signal as set of values in multiple frequency bands, wherein a first set of values in multiple frequency bands represents the first received signal and a second set of values in multiple frequency bands represents the second received signal;
• and
• wherein the processing module subtracting the second set of values in multiple frequency bands from the first set of values in multiple frequency bands in the frequency domain to obtain a third set of frequency bands, wherein the third set of frequency bands represents a third signal corresponding to the biological parameter of the tissue.