Search results for: Jerald Yoo
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IEEE Journal of Solid-State Circuits > 2017 > 52 > 10 > 2690 - 2702
This paper presents a body-coupled communication (BCC) transceiver (TRX) that mitigates all the practical impairments of the body channel at once. The proposed pseudo orthogonal frequency-division multiplexing (P-OFDM) TRX combines baseband BPSK–OFDM with frequency-shift keying (FSK) to alleviate the impacts of variable ground effect and variable skin-electrode contact impedance, which have been the...
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Body Coupled Communication (BCC) utilizes human body itself as a communication medium to provide energy-efficient connectivity between nodes on or around the body. Although BCC is an attractive way for composing a Body Area Network (BAN), the BCC still has several challenges to overcome to be commercially viable. These challenges include 1) varying channel gain over space, time and subject, 2) varying...
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This paper presents the design and modeling of an inductive wireless power transfer by utilizing printed spiral inductors on the surface of a medical hydrocolloid dressing. Hydrocolloid is a flexible and bio-compatible polymeric dressing that is medically used and approved. In this work, the dressings with planar dimensions of 10cm×10cm and thickness of less than 1mm are used as flexible substrates...
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IEEE Journal of Solid-State Circuits > 2017 > 52 > 3 > 757 - 768
A power-efficient body-coupled communication pseudo orthogonal frequency-division multiplexing (P-OFDM) transceiver (TRX) is presented for binaural hearing aids (BHAs). Channel measurements are performed for different body postures between human head-to-hand and ear-to-ear to characterize the body channel path loss. The TRX exploits baseband 16-quadrature amplitude modulation OFDM symbols transmitted...
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A Hybrid OFDM transceiver for the head- and body-area network is presented. This is the first transceiver in the literature that mitigates all the body channel impairments at once. It combines baseband BPSK-OFDM with FSK to alleviate the impacts of variable ground effect and signal multipath on the body channel quality with measured BER improvement of >70% compared to FSK modulation. It can tolerate...
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A 1- to 8-ch scalable pMUT interface system with on-chip aberration compensation is presented for portable ultrasonic imaging applications. The system overcomes the necessity of area and power reduction for large ultrasonic arrays and presents the first hardware implementation on-chip calibration to improve the signal quality. The Charge Redistribution Transmitter (CR-TX) saves power by 32.8% while...
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IEEE Journal of Biomedical and Health Informatics > 2016 > 20 > 4 > 996 - 1007
This paper presents the design of an area- and energy-efficient closed-loop machine learning-based patient-specific seizure onset and termination detection algorithm, and its on-chip hardware implementation. Application- and scenario-based tradeoffs are compared and reviewed for seizure detection and suppression algorithm and system which comprises electroencephalography (EEG) data acquisition, feature...
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Classification of EEG under wearable environment faces many challenges including motion artifact, electrode DC offset, noise and limited available energy source. This paper describes the design consideration of a multi-channel machine-learning based EEG classification and recording processors for wearable form-factor sensors. The goal is to optimize the detection performance while balancing the analog...
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With the world aging, chronic diseases are becoming the major causes of death around the world. For example, according to US National Center for Health Statistics, major chronic disease such as heart disease, cerebrovascular disease, and diabetes mellitus account for 35.6% of death in US in the year 2005 [1] (Fig. 10.1). An important perspective of the chronic diseases is that the sooner they are...
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IEEE Transactions on Biomedical Circuits and Systems > 2016 > 10 > 1 > 49 - 60
A non-linear support vector machine (NLSVM) seizure classification SoC with 8-channel EEG data acquisition and storage for epileptic patients is presented. The proposed SoC is the first work in literature that integrates a feature extraction (FE) engine, patient specific hardware-efficient NLSVM classification engine, 96 KB SRAM for EEG data storage and low-noise, high dynamic range readout circuits...
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IEEE Journal of Solid-State Circuits > 2015 > 50 > 11 > 2728 - 2740
A 16-channel noninvasive closed-loop beginning- and end-of-seizure detection SoC is presented. The dual-channel charge recycled (DCCR) analog front end (AFE) achieves chopping and time-multiplexing an amplifier between two channels simultaneously which exploits fast-settling DC servo-loop with current consumption and NEF of $0.9\;\upmu\text{A}$
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This paper presents a power-efficient non-invasive transcranial electrical stimulator (tES) with patient-specific impedance adaptation. The proposed tES exploits the varying skin-electrode impedance which results in different RC relaxation time, where the tES adapts the number of pulses to deliver a constant charge. This eliminates the need of an additional current source for impedance monitoring...
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This paper presents an area-power-efficient 16-channel seizure onset and termination detection processor with patient-specific machine learning techniques. This is the first work in literature to report an on-chip classification to detect both start and end of seizure event simultaneously with high accuracy. Frequency-Time Division Multiplexing (FTDM) filter architecture and Dual-Detector Architecture...
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An in-depth investigation of the Body Channel Communication (BCC) under the environment set according to the IEEE 802.15.6 Body Area Network (BAN) standard is conducted to observe and characterize the human body as a communication medium. A thorough measurement of the human head as part of the human channel is also carried out. Human forehead, head to limb, and ear to ear channel is characterized...
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An interference and multipath resilient Body Channel Communication transceiver with ground effect cancellation for binaural hearing aids application is presented. The channel characteristics are measured between the intended points of transmission and reception to measure the path loss. The energy efficient transceiver is based on Hybrid OFDM folded in FSK modulated signal to mitigate the multipath...
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This paper describes the design and implementation of a fully integrated Tx/Rx front-end interface for Doppler Imaging with Piezoelectric Micromachined Ultrasonic Transducer (pMUT). The 4-Level Time Gain Compensation (QL-TGC) readout channel with an integrated biasing bank reduces Rx power with satisfactory noise performance (NF=17) and minimal area. The 65nm CMOS chip occupies 200 × 300 μm and has...
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The most common operation of an IoT sensor is that of short activity bursts separated by long time intervals in sleep or listen modes. During the data bursts, sensed information has to be reliably communicated in real time without draining the energy resources of the sensor node. One way to save such resources is to efficiently code the data burst, use single-channel communication, and adopt ultra-low-power...
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Multichannel EEG seizure detection SoCs are widely used in medical practice and in research [1]-[3]. Due to huge variation in seizure patterns, patient-specific seizure detection is very crucial. [1], [2] presents 8-channel (ch) SoCs with moderate latency (∼2s) but without seizure termination detection and stimulation. [3] implements a closed-loop SoC but is not patient-specific, and moreover, is...
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IEEE Journal of Solid-State Circuits > 2014 > 49 > 9 > 1995 - 2004
<?Pub Dtl?>This paper presents transceivers and a wireless power delivery system for a Body-Area Network (BAN) that uses an e-textiles-based physical layer (PHY) capable of linking a diverse set of sensor nodes monitoring vital signs on the user's body. A central base station in the network controls power delivery and communication resource allotment for every node using a general-purpose on-chip...
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This paper presents an 8-channel electroencephalograph (EEG) classification processor for seizure detection and recording. To integrate 8 channels, an area- and energy-efficient filter architecture using Distributed Quad-LUT (DQ-LUT) is proposed, which reduces area by 64.2% with minimal overhead in power-delay product. The on-chip patient specific classification with a Linear Support-Vector Machine...
