Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463316
T. J. Hamilton, C. Jin, J. Tapson, A. V. Schaik
In this paper we present the circuits for a 2-D silicon cochlea whose basilar membrane resonant elements are constructed using oscillators whose dynamic behaviour is governed by the Hopf differential equation. By using Hopf oscillators we are able to model some of the behaviour of the outer hair cells (OHCs) whose action is responsible for the cochlea's nonlinear behaviour.
{"title":"A 2-D Cochlea with Hopf Oscillators","authors":"T. J. Hamilton, C. Jin, J. Tapson, A. V. Schaik","doi":"10.1109/BIOCAS.2007.4463316","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463316","url":null,"abstract":"In this paper we present the circuits for a 2-D silicon cochlea whose basilar membrane resonant elements are constructed using oscillators whose dynamic behaviour is governed by the Hopf differential equation. By using Hopf oscillators we are able to model some of the behaviour of the outer hair cells (OHCs) whose action is responsible for the cochlea's nonlinear behaviour.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133284186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463318
Peng Xu, T. Horiuchi, A. Sarje, P. Abshire
We report a stochastic dynamical synapse for VLSI spiking neural systems. The compactness of the circuit, real-time stochastic behavior, and probability tuning make it well suitable to implement stochastic synapses with variety of dynamics. The stochastic synapse implements short-term depression (STD) using a subtractive single release model. Preliminary experimental results show a good match with theoretical predictions. The output from the stochastic synapse with STD has negative autocorrelation and lower power spectral density at low frequencies which can remove the information redundancy in the input spike train. The mean transmission probability is inversely proportional to the input spike rate which has been suggested as an automatic gain control mechanism in neural systems. The silicon stochastic synapse with plasticity could potentially be a powerful addition to existing deterministic VLSI spiking neural systems.
{"title":"Stochastic Synapse with Short-Term Depression for Silicon Neurons","authors":"Peng Xu, T. Horiuchi, A. Sarje, P. Abshire","doi":"10.1109/BIOCAS.2007.4463318","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463318","url":null,"abstract":"We report a stochastic dynamical synapse for VLSI spiking neural systems. The compactness of the circuit, real-time stochastic behavior, and probability tuning make it well suitable to implement stochastic synapses with variety of dynamics. The stochastic synapse implements short-term depression (STD) using a subtractive single release model. Preliminary experimental results show a good match with theoretical predictions. The output from the stochastic synapse with STD has negative autocorrelation and lower power spectral density at low frequencies which can remove the information redundancy in the input spike train. The mean transmission probability is inversely proportional to the input spike rate which has been suggested as an automatic gain control mechanism in neural systems. The silicon stochastic synapse with plasticity could potentially be a powerful addition to existing deterministic VLSI spiking neural systems.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133132249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463331
Ka Leong Tsang, Jie Yuan
In this paper, a micropower current sample- and-hold front-end is designed for weak current bio-medical applications in a 0.35-mum standard CMOS process. The design reduces the distortion of the current-mode sample-and-hold stage by exploiting the exponential I-V relationship of weakly-inverted MOS transistors. The design and optimization process for the stage is introduced in the paper. With the optimized design, SPICE simulation shows that the sample-and-hold stage can achieve over 60 dB SNDR at the sampling rate of 50 kS/s, with the input signal at the Nyquist frequency of 24 kHz. The input current range is 100 nA. The power consumption of the stage is about 3.6 muW.
{"title":"A 50kS/s 10bit Micropower Current S/H Cell for Weak Current Bio-medical Applications","authors":"Ka Leong Tsang, Jie Yuan","doi":"10.1109/BIOCAS.2007.4463331","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463331","url":null,"abstract":"In this paper, a micropower current sample- and-hold front-end is designed for weak current bio-medical applications in a 0.35-mum standard CMOS process. The design reduces the distortion of the current-mode sample-and-hold stage by exploiting the exponential I-V relationship of weakly-inverted MOS transistors. The design and optimization process for the stage is introduced in the paper. With the optimized design, SPICE simulation shows that the sample-and-hold stage can achieve over 60 dB SNDR at the sampling rate of 50 kS/s, with the input signal at the Nyquist frequency of 24 kHz. The input current range is 100 nA. The power consumption of the stage is about 3.6 muW.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124276139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463294
Félix Chénier, Mohamad Sawan
A new portable brain imaging device based on continuous-wave functional near-infrared spectrometry (fNIRS) is presented. The source-detector part is composed of a multi-wavelength LED and a silicon photodetector that are directly placed on the scalp of the subject. The dimensions of the proposed device are small, as it has to be mounted on the head of an adult person. Acquired data are transmitted in real-time to a laptop for post processing using Matlab. Time- multiplexed light is used to achieve a higher SNR while keeping the device safe for long-term wearing. Preliminary evaluation on adults gave the expected accuracy and compare well with fNIRS characteristics found in literature, that are collected from bulky equipment. With a noise figure of -47 dB and a sampling rate of 23 Hz, the presented device is appropriate to isolate hemodynamic variations, which are strongly related to local cerebral activity.
{"title":"A New Brain Imaging Device Based on fNIRS","authors":"Félix Chénier, Mohamad Sawan","doi":"10.1109/BIOCAS.2007.4463294","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463294","url":null,"abstract":"A new portable brain imaging device based on continuous-wave functional near-infrared spectrometry (fNIRS) is presented. The source-detector part is composed of a multi-wavelength LED and a silicon photodetector that are directly placed on the scalp of the subject. The dimensions of the proposed device are small, as it has to be mounted on the head of an adult person. Acquired data are transmitted in real-time to a laptop for post processing using Matlab. Time- multiplexed light is used to achieve a higher SNR while keeping the device safe for long-term wearing. Preliminary evaluation on adults gave the expected accuracy and compare well with fNIRS characteristics found in literature, that are collected from bulky equipment. With a noise figure of -47 dB and a sampling rate of 23 Hz, the presented device is appropriate to isolate hemodynamic variations, which are strongly related to local cerebral activity.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129284199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463334
Nicolas de Vicq, Frederic Robert, J. Penders, Bert Gyselinckx, T. Torfs
This paper reports the development of a Wireless Body Area Network (WBAN) for sleep staging applications. A prototype biopotential sensor node has been designed for monitoring a multitude of biopotential signals. A system consisting of three of these nodes packaged in a headband enables wireless sleep stage monitoring. Preliminary results obtained from a one-night test on a healthy patient suggest that the proposed system is suitable for sleep staging applications. By removing most of the wires, the proposed system improves the patient's comfort and the quality of the signals during sleep studies. It paves the way towards remote sleep monitoring and telemedicine applications.
{"title":"Wireless Body Area Network for Sleep Staging","authors":"Nicolas de Vicq, Frederic Robert, J. Penders, Bert Gyselinckx, T. Torfs","doi":"10.1109/BIOCAS.2007.4463334","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463334","url":null,"abstract":"This paper reports the development of a Wireless Body Area Network (WBAN) for sleep staging applications. A prototype biopotential sensor node has been designed for monitoring a multitude of biopotential signals. A system consisting of three of these nodes packaged in a headband enables wireless sleep stage monitoring. Preliminary results obtained from a one-night test on a healthy patient suggest that the proposed system is suitable for sleep staging applications. By removing most of the wires, the proposed system improves the patient's comfort and the quality of the signals during sleep studies. It paves the way towards remote sleep monitoring and telemedicine applications.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125605468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463344
W. Karlen, C. Mattiussi, D. Floreano
In this paper we describe a method to classify online sleep/wake states of humans based on cardiorespiratory signals for wearable applications. The method is designed to be embedded in a portable microcontroller device and to cope with the resulting tight power restrictions. The method uses a Fast Fourier Transform as the main feature extraction method and an adaptive feed-forward Artificial Neural Network as a classifier. Results show that when the network is trained on a single user, it can correctly classify on average 95.4% of unseen data from the same user. The accuracy of the method in multi-user conditions is lower (89.4%). This is still comparable to actigraphy methods, but our method classifies wake periods considerably better.
{"title":"Adaptive Sleep/Wake Classification Based on Cardiorespiratory Signals for Wearable Devices","authors":"W. Karlen, C. Mattiussi, D. Floreano","doi":"10.1109/BIOCAS.2007.4463344","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463344","url":null,"abstract":"In this paper we describe a method to classify online sleep/wake states of humans based on cardiorespiratory signals for wearable applications. The method is designed to be embedded in a portable microcontroller device and to cope with the resulting tight power restrictions. The method uses a Fast Fourier Transform as the main feature extraction method and an adaptive feed-forward Artificial Neural Network as a classifier. Results show that when the network is trained on a single user, it can correctly classify on average 95.4% of unseen data from the same user. The accuracy of the method in multi-user conditions is lower (89.4%). This is still comparable to actigraphy methods, but our method classifies wake periods considerably better.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134320717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463298
Mel Ho, T. Lande, C. Toumazou
This paper describes a novel approach to hardware efficient computing of the LF/HF ratio as required in heart rate variability (HRV) analysis. Heart rate data are converted into a bit stream vie delta-sigma modulation. The bit stream is filtered in the LF and HF sub-bands using novel hardware architecture. Sub-band spectral content is estimated from the filtered signals. The proposed algorithm and hardware architecture is extremely efficient, making continuous real-time HRV analysis possible in low-power microelectronics.
{"title":"Efficient Computation of the LF/HF Ratio in Heart Rate Variability Analysis Based on Bitstream Filtering","authors":"Mel Ho, T. Lande, C. Toumazou","doi":"10.1109/BIOCAS.2007.4463298","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463298","url":null,"abstract":"This paper describes a novel approach to hardware efficient computing of the LF/HF ratio as required in heart rate variability (HRV) analysis. Heart rate data are converted into a bit stream vie delta-sigma modulation. The bit stream is filtered in the LF and HF sub-bands using novel hardware architecture. Sub-band spectral content is estimated from the filtered signals. The proposed algorithm and hardware architecture is extremely efficient, making continuous real-time HRV analysis possible in low-power microelectronics.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114311038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463354
Shih-Lun Chen, Ho-Yin Lee, Chiung-An Chen, Chin-Chun Lin, C. Luo
A four levels hierarchy wireless body sensor network (WBSN) is proposed for monitoring healthcare applications. It is separated into communication and control systems. In the communication system, the carrier frequency used in the human body is 402-405 MHz as medical implant communication systems (MICS) band by FCC and the coexistent wireless communication system (2.4 / 60 GHz) was used to transmit the merged biomedical data in the higher levels of the communication system. An adaptive low power and variable resolution control systems are designed into the control system. In order to improve the performance, a communication cycle is created for synchronizing the WBSN system with pipeline control. Each sensor node consists of a micro control unit (MCU), variable sample rate generator, sensor, ADC, data encoder, 402-405 MHz RF transceiver, and antenna. This paper presents a WBSN system, which not only gains the benefits of more flexible, easy development, run-time reconfigurable and variable resolution, but also significantly reduces considerable power consumptions with adaptive low power design.
{"title":"A Wireless Body Sensor Network System for Healthcare Monitoring Application","authors":"Shih-Lun Chen, Ho-Yin Lee, Chiung-An Chen, Chin-Chun Lin, C. Luo","doi":"10.1109/BIOCAS.2007.4463354","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463354","url":null,"abstract":"A four levels hierarchy wireless body sensor network (WBSN) is proposed for monitoring healthcare applications. It is separated into communication and control systems. In the communication system, the carrier frequency used in the human body is 402-405 MHz as medical implant communication systems (MICS) band by FCC and the coexistent wireless communication system (2.4 / 60 GHz) was used to transmit the merged biomedical data in the higher levels of the communication system. An adaptive low power and variable resolution control systems are designed into the control system. In order to improve the performance, a communication cycle is created for synchronizing the WBSN system with pipeline control. Each sensor node consists of a micro control unit (MCU), variable sample rate generator, sensor, ADC, data encoder, 402-405 MHz RF transceiver, and antenna. This paper presents a WBSN system, which not only gains the benefits of more flexible, easy development, run-time reconfigurable and variable resolution, but also significantly reduces considerable power consumptions with adaptive low power design.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123302070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-01DOI: 10.1109/BIOCAS.2007.4463336
A. Cabuk, A. Do, C. Boon, K. Yeo, M. Do
A fully integrated 2.4-GHz receiver targeting body sensor network applications is designed in 0.18-μm CMOS technology. The receiver includes a subthreshold biased low-noise amplifier (LNA), a passive mixer, two variable gain amplifiers (VGA) and a channel select filter (CSF). Several circuit design techniques are employed in order to reduce the silicon area and the power consumption of the receiver. The measured gain and the noise figure of the LNA are 20dB and 5.2dB, respectively. These values are obtained with a very low current of 630 μA from a 1.8-V supply. By employing a digitally switched-load gain variation scheme, the gain of the first VGA and the second VGA can be varied linearly from -18.5dB to +24.5dB, and from +16dB to +54dB, respectively. Input-referred noise at maximum gain mode is less than 17nV/radicHz and the current consumption is less than 400 μA from a 1.8-V supply for both circuits. The VGAs exhibit excellent linearity in terms of gain variation and gain compression. Small silicon area is achieved by avoiding bulky passive components.
{"title":"A fully integrated 2.4-GHz receiver in a 0.18-μm CMOS process for low-power body-area-network applications","authors":"A. Cabuk, A. Do, C. Boon, K. Yeo, M. Do","doi":"10.1109/BIOCAS.2007.4463336","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463336","url":null,"abstract":"A fully integrated 2.4-GHz receiver targeting body sensor network applications is designed in 0.18-μm CMOS technology. The receiver includes a subthreshold biased low-noise amplifier (LNA), a passive mixer, two variable gain amplifiers (VGA) and a channel select filter (CSF). Several circuit design techniques are employed in order to reduce the silicon area and the power consumption of the receiver. The measured gain and the noise figure of the LNA are 20dB and 5.2dB, respectively. These values are obtained with a very low current of 630 μA from a 1.8-V supply. By employing a digitally switched-load gain variation scheme, the gain of the first VGA and the second VGA can be varied linearly from -18.5dB to +24.5dB, and from +16dB to +54dB, respectively. Input-referred noise at maximum gain mode is less than 17nV/radicHz and the current consumption is less than 400 μA from a 1.8-V supply for both circuits. The VGAs exhibit excellent linearity in terms of gain variation and gain compression. Small silicon area is achieved by avoiding bulky passive components.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125429486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/BIOCAS.2007.4463326
A. McEwan, J. Tapson, A. van Schaik, D. Holder
Traditional impedance tomography measurement systems make sequential four-terminal impedance measurements. Potentially faster frequency- and code-division multiplexed impedance measurement systems require that simultaneous current injection and voltage measurement take place at all terminals, making four-terminal measurements difficult. We describe an electrode interface circuit that simultaneously implements balanced current injection, and current and potential measurement, allowing four-terminal measurements on sets of multiple electrodes using these faster techniques. Circuit results show that accurate simultaneous four-terminal measurements are possible, thereby enabling faster impedance tomography systems.
{"title":"Electrode Circuits for Frequency- and Code-Division Multiplexed Impedance Tomography","authors":"A. McEwan, J. Tapson, A. van Schaik, D. Holder","doi":"10.1109/BIOCAS.2007.4463326","DOIUrl":"https://doi.org/10.1109/BIOCAS.2007.4463326","url":null,"abstract":"Traditional impedance tomography measurement systems make sequential four-terminal impedance measurements. Potentially faster frequency- and code-division multiplexed impedance measurement systems require that simultaneous current injection and voltage measurement take place at all terminals, making four-terminal measurements difficult. We describe an electrode interface circuit that simultaneously implements balanced current injection, and current and potential measurement, allowing four-terminal measurements on sets of multiple electrodes using these faster techniques. Circuit results show that accurate simultaneous four-terminal measurements are possible, thereby enabling faster impedance tomography systems.","PeriodicalId":273819,"journal":{"name":"2007 IEEE Biomedical Circuits and Systems Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128484158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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