Abstract: A circuit includes an interference frequency tracking circuit, a PLI synthesizer circuit, and a summing circuit. The interference frequency tracking circuit is configured to track a frequency of an interference signal derived from a target signal, and provide a frequency selection value representing the frequency of the interference signal. The PLI synthesizer circuit is configured to generate, based on the frequency selection value, a correction signal at the frequency of the interference signal, adjust a phase of the correction signal to match a phase of the interference signal in the target signal, and adjust an amplitude of the correction signal to match an amplitude of the interference signal in the target signal. The summing circuit is configured to subtract the correction signal from the target signal.

Abstract: An ECG signal acquisition system includes a first amplifier which has a non-inverting input adapted to be coupled to a first differential input, an inverting input adapted to be coupled to a second differential input, and an output. The system includes first and second biasing resistors coupled between the non-inverting and inverting inputs of the first amplifier. The system includes an average estimation circuit which has a first input coupled to the non-inverting input of the first amplifier and a second input coupled to the inverting input of the first amplifier. The system includes a driver amplifier which has an inverting input coupled to the output of the average estimation circuit, a non-inverting input coupled to receive a reference common-mode voltage, and an output. The system includes a low-pass filter coupled between the output of the driver amplifier and the biasing resistors.

Abstract: An example apparatus includes: calibration circuitry configured to determine a second current at a second terminal of a second impedance circuit based on a first parasitic capacitance, a first impedance value, a third impedance value, a first voltage, and a second voltage; determine a third voltage at a second terminal of a second impedance circuit based on the first parasitic capacitance, a second impedance value, the third impedance value, the second voltage, and the second current; and determine a second parasitic capacitance between the second terminal of the second impedance circuit and the second terminal of a fifth impedance circuit based on the second current, the third voltage, a third current at the second terminal of the fifth impedance circuit, and a fourth voltage at the second terminal of the fifth impedance circuit.

Abstract: The disclosure provides a measurement circuit. The measurement circuit includes a control engine. An excitation source is coupled to the control engine. A first set of electrodes and a second set of electrodes are coupled to the excitation source and receive current from the excitation source. The control engine operates the excitation source in a first mode and a second mode. The control engine, in the first mode, measures a parasitic impedance associated with the first and the second set of electrodes, and the control engine, in the second mode, measures an impedance of the first and the second set of electrodes and of an external object.

Abstract: An ECG signal acquisition system includes a first amplifier which has a non-inverting input adapted to be coupled to a first differential input, an inverting input adapted to be coupled to a second differential input, and an output. The system includes first and second biasing resistors coupled between the non-inverting and inverting inputs of the first amplifier. The system includes an average estimation circuit which has a first input coupled to the non-inverting input of the first amplifier and a second input coupled to the inverting input of the first amplifier. The system includes a driver amplifier which has an inverting input coupled to the output of the average estimation circuit, a non-inverting input coupled to receive a reference common-mode voltage, and an output. The system includes a low-pass filter coupled between the output of the driver amplifier and the biasing resistors.

Abstract: An apparatus comprises a transceiver (Tx/Rx) printed circuit board (PCB) with a top surface and a bottom surface and a power supply PCB. The Tx/Rx PCB includes two transmitter devices, each comprising a number N of channels. A first transmitter device is arranged on the bottom surface and a second transmitter device is arranged on the top surface over the first transmitter device. One or more pins of the second transmitter device are shorted with one or more pins of the first transmitter device with the same function. An analog front end (AFE) device comprising N input channels is arranged on the top surface of the Tx/Rx PCB, and a digital signal processor is coupled to the AFE device. The power supply PCB comprises a power supply module configured to provide a plurality of supply voltages to the Tx/Rx PCB and the power supply PCB.

Abstract: An apparatus comprises a transceiver (Tx/Rx) printed circuit board (PCB) with a top surface and a bottom surface and a power supply PCB. The Tx/Rx PCB includes two transmitter devices, each comprising a number N of channels. A first transmitter device is arranged on the bottom surface and a second transmitter device is arranged on the top surface over the first transmitter device. One or more pins of the second transmitter device are shorted with one or more pins of the first transmitter device with the same function. An analog front end (AFE) device comprising N input channels is arranged on the top surface of the Tx/Rx PCB, and a digital signal processor is coupled to the AFE device. The power supply PCB comprises a power supply module configured to provide a plurality of supply voltages to the Tx/Rx PCB and the power supply PCB.

Abstract: The disclosure provides a measurement circuit. The measurement circuit includes a control engine. An excitation source is coupled to the control engine. A first set of electrodes and a second set of electrodes are coupled to the excitation source and receive current from the excitation source. The control engine operates the excitation source in a first mode and a second mode. The control engine, in the first mode, measures a parasitic impedance associated with the first and the second set of electrodes, and the control engine, in the second mode, measures an impedance of the first and the second set of electrodes and of an external object.