A method and system for spectroscopic measurement of a characteristic of a biological tissue is provided. The method includes the steps of: (1) using at least one light source to emit light that penetrates the biological tissue； (2) using at least one light detector to detect light emitted by the at least one light source and passed through the biological tissue, and to convert the detected light into a detection signal, the detection signal including an unwanted noise component； and (3) using a processor to process the detection signal and to determine an adjusted peak-to-peak amplitude value that is representative of an amplitude of the detection signal adjusted for the unwanted noise component.
