Abstract: An apparatus is disclosed for determining validity of a measured in-blood percentage of oxygenated hemoglobin. The apparatus has multiple pulse oximetry channels having at least three light sources of at least three distinct wavelengths, which are detected and converted to digital signals. The light sources are selectively activated, and two or more estimated in-blood percentages of oxygenated hemoglobin are calculated. It is determined whether a signal quality associated with the calculated in-blood percentages exceeds a predetermined accuracy threshold, and an associated validity indication is provided.

Abstract: An apparatus is disclosed for determining validity of a measured in-blood percentage of oxygenated hemoglobin. The apparatus has multiple pulse oximetry channels having at least three light sources of at least three distinct wavelengths, which are detected and converted to digital signals. The light sources are selectively activated, and two or more estimated in-blood percentages of oxygenated hemoglobin are calculated. It is determined whether a signal quality associated with the calculated in-blood percentages exceeds a predetermined accuracy threshold, and an associated validity indication is provided.

Abstract: An electronic fitness device comprises an optical transmitter, a first lens, an optical receiver, and a second lens. The optical transmitter is operable to transmit an optical signal. The first lens covers at least a portion of the optical transmitter and is operable to direct the optical signal into the skin of a user in a first direction outward from a center of the electronic fitness device. The optical receiver is operable to receive optical signals modulated by the skin of the user and to generate a photoplethysmogram (PPG) signal resulting from the optical signal. The second lens covers at least a portion of the optical receiver and is operable to receive a modulated optical signal from the skin of the user in a second direction inward toward the center of the electronic fitness device and to direct the modulated optical signal toward the optical receiver.

Abstract: An electronic fitness device comprises an optical transmitter, a first lens, an optical receiver, and a second lens. The optical transmitter is operable to transmit an optical signal. The first lens covers at least a portion of the optical transmitter and is operable to direct the optical signal into the skin of a user in a first direction outward from a center of the electronic fitness device. The optical receiver is operable to receive optical signals modulated by the skin of the user and to generate a photoplethysmogram (PPG) signal resulting from the optical signal. The second lens covers at least a portion of the optical receiver and is operable to receive a modulated optical signal from the skin of the user in a second direction inward toward the center of the electronic fitness device and to direct the modulated optical signal toward the optical receiver.