System and method for generating a PPG signal
First Claim
1. A fitness monitor for monitoring a cardiac signal of a user, the device comprising:
- an emitter configured to output light toward skin of the user;
an emitter driver configured to cause the emitter to output light at one of a plurality of intensity levels;
a receiver configured to receive a reflection of the transmitted light and generate a light intensity signal based on the received reflection;
a photometric front end configured to receive the light intensity signal and generate a photoplethysmogram (PPG) signal based on the light intensity signal, the PPG signal including a cardiac signal of the user;
a memory device configured to store a reference value characterizing performance of the photometric front end based on a variability of the PPG signal output from the photometric front end during idle operation; and
a processor communicatively coupled to the emitter, the receiver, photometric front end and the memory device, the processor configured to;
select a first intensity level for the emitter to output light,transmit a first output control signal including the selected first intensity level to the emitter driver causing the emitter to output light at the selected first intensity level,determine a DC component of a PPG signal received from photometric front end,select a second intensity level based on a comparison of the determined DC component of the received PPG signal with the stored reference value,transmit a second output control signal including the selected second intensity level to the emitter driver causing the emitter to output light at the selected second intensity level, andidentify the cardiac component in the received PPG signal.
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Accused Products
Abstract
Characterization of a fitness monitor based on its operation enables a processor to account for variations in device operating modes and biometric characteristics of the user. The fitness monitor includes an emitter (e.g., LED) for transmitting light toward skin of the user, a receiver (e.g., photodiode) for receiving a reflection of the transmitted light, a photometric front end for generating a photoplethysmogram (PPG) signal based on the received reflection, and a processor configured to select an intensity level for the emitter based on a comparison of a determined component of the PPG signal and a reference value. The reference value, which may characterize the fitness monitor based on a determined variability or range of the PPG signal, may be utilized by the processor to improve or maintain the signal quality of the PPG signal to enable determination of a cardiac component and/or reduction of power consumption by the fitness device.
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Citations
20 Claims
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1. A fitness monitor for monitoring a cardiac signal of a user, the device comprising:
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an emitter configured to output light toward skin of the user; an emitter driver configured to cause the emitter to output light at one of a plurality of intensity levels; a receiver configured to receive a reflection of the transmitted light and generate a light intensity signal based on the received reflection; a photometric front end configured to receive the light intensity signal and generate a photoplethysmogram (PPG) signal based on the light intensity signal, the PPG signal including a cardiac signal of the user; a memory device configured to store a reference value characterizing performance of the photometric front end based on a variability of the PPG signal output from the photometric front end during idle operation; and a processor communicatively coupled to the emitter, the receiver, photometric front end and the memory device, the processor configured to; select a first intensity level for the emitter to output light, transmit a first output control signal including the selected first intensity level to the emitter driver causing the emitter to output light at the selected first intensity level, determine a DC component of a PPG signal received from photometric front end, select a second intensity level based on a comparison of the determined DC component of the received PPG signal with the stored reference value, transmit a second output control signal including the selected second intensity level to the emitter driver causing the emitter to output light at the selected second intensity level, and identify the cardiac component in the received PPG signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A fitness monitor for monitoring a cardiac signal of a user, the device comprising:
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an emitter configured to output light toward skin of the user; an emitter driver configured to cause the emitter to output light at one of a plurality of intensity levels; a receiver configured to receive a reflection of the transmitted light and generate a light intensity signal based on the received reflection; a photometric front end configured to receive the light intensity signal and generate a photoplethysmogram (PPG) signal based on the light intensity signal, the PPG signal including a cardiac signal; a reference value characterizing performance of the photometric front end based on a variability of the PPG signal output from the photometric front end when the fitness monitor is not proximate to the skin of the user; a memory device configured to store the reference value; and a processor communicatively coupled to the emitter, the receiver, photometric front end and the memory device, the processor configured to; select a first intensity level for the emitter to output light, transmit a first output control signal including the selected first intensity level to the emitter driver causing the emitter to output light at the selected first intensity level, determine a DC component of a PPG signal received from the photometric front end, select a second intensity level based on a comparison of the determined DC component of the received PPG signal with the stored reference value, transmit a second output control signal including the selected second intensity level to the emitter driver causing the emitter to output light at the selected second intensity level, and identify the cardiac component in the received PPG signal. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A fitness monitor for monitoring a cardiac signal of a user comprising an emitter configured to output light toward skin of the user, an emitter driver configured to cause the emitter to output light at one of a plurality of intensity levels, a receiver configured to receive a reflection of the transmitted light and generate a light intensity signal based on the received reflection, a photometric front end configured to receive the light intensity signal and generate a photoplethysmogram (PPG) signal based on the light intensity signal and representing the cardiac signal, and a tangible non-transitory computer-readable medium storing instructions and a reference value characterizing performance of the photometric front end based on a variability of the PPG signal output from the photometric front end during idle operation, wherein the instructions, when executed by one or more processors, cause the fitness monitor to:
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select a first intensity level for the emitter to output light, transmit a first output control signal including the selected first intensity level to the emitter driver causing the emitter to output light at the selected first intensity level, determine a DC component of the PPG signal, select a second intensity level based on a comparison of the determined DC component of the PPG signal with the stored reference value, transmit a second output control signal including the selected second intensity level to the emitter driver causing the emitter to output light at the selected second intensity level, and identify the cardiac component in the PPG signal.
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Specification