An Adaptive Averaging Low Noise Front-End for Central and Peripheral Nerve Recording.

An adaptive averaging low noise analog front-end (AFE) is presented for central and peripheral nerve recording applications. The proposed topology allows users to trade off, on the fly, between input referred noise and the number of channels via averaging. The new low noise amplifier (LNA) utilizes a complementary doubled input transconductance ( ) topology to effectively increase the noise efficiency factor (NEF) without chopping or use of a costly BiCMOS process.

Supply-Doubled Pulse-Shaping High Voltage Pulser for CMUT Arrays.

A supply-doubled pulse-shaping high voltage (HV) pulser is presented for medical ultrasound imaging applications, particularly those that use capacitive micromachined ultrasonic transducers (CMUT). The pulser employs a bootstrap circuit combined with dynamically-biased stacked transistors, which allow HV operation above process limit without lowering device reliability. The new pulser overcomes supply voltage limitation of conventional unipolar pulsers by generating output signals that are almost twice the supply level.

Universal Pre-Ejection Period Estimation Using Seismocardiography: Quantifying the Effects of Sensor Placement and Regression Algorithms.

Seismocardiography (SCG), the measurement of local chest vibrations due to the heart and blood movement, is a non-invasive technique to assess cardiac contractility via systolic time intervals such as the pre-ejection period (PEP). Recent studies show that SCG signals measured before and after exercise can effectively classify compensated and decompensated heart failure (HF) patients through PEP estimation. However, the morphology of the SCG signal varies from person to person and sensor placement making it difficult to automatically estimate PEP from SCG and electrocardiogram signals using a global model.

Automatic Detection of Seismocardiogram Sensor Misplacement for Robust Pre-Ejection Period Estimation in Unsupervised Settings.

Seismocardiography (SCG), the measurement of the local chest vibrations due to the movements of blood and the heart, is a non-invasive technique for assessing myocardial contractility via the pre-ejection period (PEP). Recently, SCG-based extraction of PEP has been shown to be an effective means of classifying decompensated from compensated heart failure patients, and thus can be potentially used for monitoring such patients at home. Accurate extraction of PEP from SCG signals hinges on lab-based population data (i.

A Multi-Cycle Q-Modulation for Dynamic Optimization of Inductive Links.

This paper presents a new method, called multi-cycle Q-modulation, which can be used in wireless power transmission (WPT) to modulate the quality factor (Q) of the receiver (Rx) coil and dynamically optimize the load impedance to maximize the power transfer efficiency (PTE) in two-coil links. A key advantage of the proposed method is that it can be easily implemented using off-the-shelf components without requiring fast switching at or above the carrier frequency, which is more suitable for integrated circuit design. Moreover, the proposed technique does not need any sophisticated synchronization between the power carrier and Q-modulation switching pulses.

A Q-Modulation Technique for Efficient Inductive Power Transmission.

A fully-integrated power management ASIC for efficient inductive power transmission has been presented capable of automatic load transformation using a method, called Q-modulation. Q-modulation is an adaptive scheme that offers load matching against a wide range of loading ( ) and coupling distance ( ) variations in inductive links to maintain high power transfer efficiency (PTE). It is suitable for inductive powering implantable microelectronic devices (IMDs), recharging mobile electronics, and electric vehicles.

An Inductively-Powered Wireless Neural Recording System with a Charge Sampling Analog Front-End.

An inductively-powered wireless integrated neural recording system (WINeR-7) is presented for wireless and battery less neural recording from freely-behaving animal subjects inside a wirelessly-powered standard homecage. The WINeR-7 system employs a novel wide-swing dual slope charge sampling (DSCS) analog front-end (AFE) architecture, which performs amplification, filtering, sampling, and analog-to-time conversion (ATC) with minimal interference and small amount of power. The output of the DSCS-AFE produces a pseudo-digital pulse width modulated (PWM) signal.

Quantitative assessment of magnetic sensor signal processing algorithms in a wireless tongue-operated assistive technology.

In this paper, we evaluate the overall performance of various magnetic-sensor signal processing (mSSP) algorithms for the Tongue Drive System based on a comprehensive dataset collected from trials with a total of eight able-bodied subjects. More specifically, we measure the performance of nine classifiers on the two-stage classification used by the mSSP algorithm, in order to learn how to improve the current algorithm. Results show that is it possible to reduce misclassification error from 5.

Wireless hippocampal neural recording via a multiple input RF receiver to construct place-specific firing fields.

This paper reports scientifically meaningful in vivo experiments using a 32-channel wireless neural recording system (WINeR). The WINeR system is divided into transmitter (Tx) and receiver (Rx) parts. On the Tx side, we had WINeR-6, a system-on-a-chip (SoC) that operated based on time division multiplexing (TDM) of pulse width modulated (PWM) samples.

An overview of the recent wideband transcutaneous wireless communication techniques.

Neuroprosthetic devices such as cochlear and retinal implants need to deliver a large volume of data from external sensors into the body, while invasive brain-computer interfaces need to deliver sizeable amounts of data from the central nervous system to target devices outside of the body. Nonetheless, the skin should remain intact. This paper reviews some of the latest techniques to establish wideband wireless communication links across the skin.

Design and Optimization of a 3-Coil Inductive Link for Efficient Wireless Power Transmission.

Inductive power transmission is widely used to energize implantable microelectronic devices (IMDs), recharge batteries, and energy harvesters. Power transfer efficiency (PTE) and power delivered to the load (PDL) are two key parameters in wireless links, which affect the energy source specifications, heat dissipation, power transmission range, and interference with other devices. To improve the PTE, a 4-coil inductive link has been recently proposed.

A novel pulse-based modulation technique for wideband low power communication with neuroprosthetic devices.

Pulse Harmonic Modulation (PHM) is a novel pulse-based (carrierless) modulation method for wideband, low power data transmission across inductive telemetry links that operate in the near-field domain. PHM utilizes two or more unidentical pulses during each bit period to minimize inter-symbol interference (ISI). In this paper, we describe the PHM concept and demonstrate its operation with a proof-of-concept prototype, which achieves a data rate of 5.

Modeling and optimization of printed spiral coils in air and muscle tissue environments.

Printed spiral coils (PSC) are viable candidates for near field wireless power transmission to the next generation of prosthetic devices with extreme size constraints. Implantable devices need to be hermetically sealed in biocompatible materials and placed in conductive environment with high permittivity, which can affect the PSC characteristics. We have constructed a detailed model that includes the effects of surrounding environment on the PSC parasitic components and eventually on the power transfer efficiency.