Wearable system for detecting and measuring biosignals
Inventors
Assignees
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Publication Number
US-10806400-B2
Publication Date
2020-10-20
Expiration Date
Abstract
A system for detecting bioelectrical signals of a user comprising: a set of sensors configured to detect bioelectrical signals from the user, each sensor in the set of sensors configured to provide non-polarizable contact at the body of the user; an electronics subsystem comprising a power module configured to distribute power to the system and a signal processing module configured to receive signals from the set of sensors; a set of sensor interfaces coupling the set of sensors to the electronics subsystem and configured to facilitate noise isolation within the system; and a housing coupled to the electronics subsystem, wherein the housing facilitates coupling of the system to a head region of the user.
Core Innovation
The invention relates to a wearable system for detecting bioelectrical signals of a user, where a set of sensors are configured to detect bioelectrical signals from the user and each sensor is proximal to a region of a scalp of the user. The system includes a set of sensor interfaces coupled to the sensors, with the sensor interfaces configured to receive the bioelectrical signals and provide pre-gain alternating current (AC) coupling and level shift to block direct current (DC) signals. The electronics subsystem receives the bioelectrical signals from the sensor interfaces and includes an analog electronics subsystem and a digital electronics subsystem distinct from and connected to the analog electronics subsystem.
To reduce noise, the analog electronics subsystem includes a hum remover configured to superimpose an ambient signal, received from the set of sensor interfaces, with a predetermined signal having a frequency outside of a frequency range of the bioelectrical signals, to produce a calibration signal. The calibration signal is applied to the user through at least one sensor of the set of sensors. The hum remover uses the calibration signal to determine a contact impedance of each individual sensor, thereby enabling noise/interference mitigation while estimating real-time contact quality.
The system architecture further includes electronics configured to separate “quiet” analog electronics from “noisy” digital electronics via an inter-board connection. The housing includes a set of arms configured to position the set of sensors proximal to the scalp of the user upon coupling of the system to the user, supporting stable sensor contact and electrical coupling through hair. The analog electronics subsystem may further include a transient-voltage protection circuit using uni-polar TVS diodes, and the electronics subsystem may include a mid-rail generator and associated AC coupling and level shifting to maintain signal balance.
Claims Coverage
The document includes two independent claims, each centered on scalp-proximal sensing with sensor-interface conditioning and a noise-reduction calibration scheme using a hum remover that superimposes an ambient signal with a predetermined out-of-band signal, while also specifying analog/digital subsystem separation and a housing that positions the sensors on the scalp.
Scalp-proximal sensor set with AC-coupled interfaces blocking DC
A set of sensors proximal to a region of a scalp detects bioelectrical signals, and a set of sensor interfaces provides pre-gain alternating current (AC) coupling and level shift configured to block direct current (DC) signals.
Hum remover using ambient signal superimposed with predetermined signal for calibration
An analog electronics subsystem includes a hum remover configured to superimpose an ambient signal from the sensor interfaces with a predetermined signal having a frequency outside of a frequency range of the bioelectrical signals to produce a calibration signal, and to apply the calibration signal to the user through at least one sensor to determine a contact impedance of each individual sensor.
Analog and distinct digital subsystems connected through inter-board connection
A digital electronics subsystem distinct from and connected to the analog electronics subsystem, wherein in one formulation the digital electronics subsystem is coupled to the analog electronics subsystem through an inter-board connection.
Housing arms positioning sensors proximal to the scalp
A housing comprising a set of arms configured to position the set of sensors proximal to the scalp of the user upon coupling of the system to the user.
Amplify and shift sensor voltages in sensor interfaces
Sensor interfaces amplify and shift bioelectrical signal voltages transmitted to an electronics subsystem.
Hum remover calibration without explicit contact-impedance determination
A hum remover configured to superimpose an ambient signal received from the sensor interfaces with a predetermined signal to produce a calibration signal, and apply the calibration signal to the user through at least one sensor.
Across the independent claims, the core coverage is a scalp-proximal bioelectrical signal detection system that blocks DC via pre-gain AC coupling and level shifting, reduces noise using a hum remover that forms a calibration signal by superimposing an ambient signal with a predetermined signal, and separates analog and digital electronics while using a housing with arms to position the sensors proximal to the scalp.
Stated Advantages
Reducing noise in a bioelectrical signal detection system.
Determining a contact impedance of each individual sensor based on the calibration signal.
Real-time contact quality estimation based on contact impedance determination.
Documented Applications
No documented applications found
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