Abstract: A circuit for expanding a dynamic range. In one embodiment, the circuit includes: a transducer generating a signal current on an output terminal in response to a physical quantity, the signal current comprising an AC current and a DC current; a dynamic range enhancement circuit having a digital control signal input terminal and producing a variable opposition current in response to a digital signal applied to the digital control signal input terminal; an amplifier; an analog to digital converter in electrical communication with the amplifier; and a digital feedback circuit in communication with the output terminal of the analog to digital converter and in electrical communication with the digital control signal input terminal of the dynamic range enhancement circuit, wherein the opposition current from the dynamic range enhancement circuit is set substantially equal to the DC current portion of the signal current from the transducer.

Abstract: A circuit for expanding a dynamic range. In one embodiment, the circuit includes: a transducer generating a signal current on an output terminal in response to a physical quantity, the signal current comprising an AC current and a DC current; a dynamic range enhancement circuit having a digital control signal input terminal and producing a variable opposition current in response to a digital signal applied to the digital control signal input terminal; an amplifier; an analog to digital converter in electrical communication with the amplifier; and a digital feedback circuit in communication with the output terminal of the analog to digital converter and in electrical communication with the digital control signal input terminal of the dynamic range enhancement circuit, wherein the opposition current from the dynamic range enhancement circuit is set substantially equal to the DC current portion of the signal current from the transducer.

Abstract: A physiological monitor for measuring a pulsatile motion signal (MoCG) that is delayed from, but at the same rate as, the heartbeat of a user. In one embodiment, the system includes a housing configured to be worn on the body of a user; at least one MoCG sensor, within the housing, that measures a pulsatile motion signal (MoCG) that is delayed from, but at the same rate as, the heartbeat of the user; and at least one data processor that calculates, solely based on an output of the at least one MoCG sensor, at least one of (i) heart rate (HR) and activity level for the user, and (ii) respiratory rate (RR), stroke volume (SV), and cardiac output (CO) for the user. In another embodiment, the at least one data processor is within the housing.