BODY-DRIVEN PSEUDORANDOM SIGNAL INJECTION FOR BIOMEDICAL ACQUISITION CHANNEL CALIBRATION

摘要

Disclosed are systems and methods for monitoring biopotential signals in biomedical devices. The disclosure provides a mixed signal background calibration that stabilizes the time-varying coupling gain between the body and an electrode due to motion artifacts. The calibration technique involves a low-level test signal in the form of a one-bit pseudorandom bit-sequence that is injected through a reference electrode to the body, detected by the sensing electrode and recorded along with the bio signals. A digital algorithm is employed in the backend to identify the acquisition channel characteristics while maintaining its normal operation of recording. Programmable gain stages in analog or digital domain(s) can be used to stabilize the overall gain of the channel. The disclosed technique is in the background and not interfering with the normal recording operation(s), and provides continuous monitoring of the ETI and continuous correction of the ensuing channel characteristic degradation due to the ETI variation.

主权项

1. A method comprising:
driving, via monitoring circuitry, a pseudorandom noise (PN) signal, said PN signal being driven to a patient's body and received by an electrode affixed to the body of the patient; synchronizing, via the monitoring circuitry, the PN signal driven to the patient body and received by the electrode; correlating, via the monitoring circuitry, the received PN signal to its original form to determine a signal-path gain A(t); detecting, via the monitoring circuitry, A(t) comprising a multiplicative motion artifact (MMA), said detection associated with a selected time duration of said correlation and determination that A(t) varies over time; and employing, via the monitoring circuitry, a digital or analog programmable gain compensator to stabilize A(t).