Method for Obtaining Heart Rate and Electronic Device

An electronic device includes a first optical transmitter, a second optical transmitter, a first optical receiver, and a second optical receiver. The first optical transmitter and the second optical transmitter may respectively transmit a first optical signal and a second optical signal with different wavelengths to a skin surface of a user. The first optical receiver may generate a first PPG signal based on a received first optical signal. The second optical receiver may generate a second PPG signal based on the received second optical signal. The second PPG signal may be used to determine a magnitude of noise in the first PPG signal.