Low-power ultrawideband wireless telemetry transceiver for medical sensor applications

An integrated CMOS ultrawideband wireless telemetry transceiver for wearable and implantable medical sensor applications is reported in this letter. This high duty cycled, noncoherent transceiver supports scalable data rate up to 10 Mb/s with energy efficiency of 0.35 nJ/bit and 6.2 nJ/bit for transmitter and receiver, respectively. A prototype wireless capsule endoscopy using the proposed transceiver demonstrated in vivo image transmission of 640 × 480 resolution at a frame rate of 2.5 frames/s with 10 Mb/s data rate.     

Low-power CMOS wireless MEMS motion sensor for physiological activity monitoring

In this paper, a short distance wireless sensor node "AccuMicroMotion" for physiological activity monitoring is proposed for detecting motions in six degrees of freedom. System architecture, relevant microstructures, and electronic circuits to implement the sensor node are presented. A three-axis microelectromechanical systems (MEMS) accelerometer and a z-axis gyroscope are designed and fabricated using a new deep-reactive ion-etch CMOS-MEMS process. The interface circuits, an analog-to-digital converter, and a wireless transmitter are designed using Taiwan Semiconductor Manufacturing Company 0.35-/spl mu/m CMOS process, wherein the interface circuits adopt chopper stabilization technique and can resolve a signal (dc to 1 kHz) as low as 200 nV from the microsensors; digitized outputs from the microsensors are transmitted by a 900-MHz amplitude-shift-keying radio-frequency transmitter that delivers a 2.2-mW power to a 50-/spl Omega/ antenna. The system draws an average current of 4.8 mA from a 3-V supply when six sensors are in operation simultaneously and provides an overall 60-dB dynamic range.     

A telemetric pressure sensor system for biomedical applications

A new implantable pressure sensor for long-term monitoring of intracranial pressure is presented. The sensor is powered by telemetry and can be interrogated wirelessly. A capacitive pressure transducer, whose capacitance is converted to a frequency-encoded signal by an application-specific integrated circuit (ASIC), senses the absolute pressure. The pressure-encoded signal, the ASIC input voltage, and onboard calibration parameters are transmitted to an external reading unit. The proposed novel packaging solution is designed for long-term stability and reliability of the sensor. The accuracy of sensor at body temperature is better than 2 mbar across a pressure range of 600-1200 mbar. The sensor is 13 mm in diameter and 4.5 mm in height.     

脉冲超宽带测控信号时延精密跟踪方法

脉冲超宽带测控新体制可有效提高测控系统的安全性能,且具有潜在的高精度测距能力.为了实现其高精度测距功能,提出了一种基于延迟锁定环路的脉冲超宽带测控信号时延精密跟踪方法.该方法在传统伪码跟踪环的基础上进行改进,利用基于非相干积分的非线性反馈环路对接收信号的脉冲相位进行精密跟踪.理论分析和仿真结果表明,该延迟锁定环路可以完成对脉冲超宽带测控信号的时延精密跟踪.与直扩测控信号相比,在相同条件下,脉冲超宽带测控信号的时延跟踪相对误差更大,但由于脉冲宽度很窄,在一定载噪比条件下,其测量精度仍可达厘米量级甚至更高.     

Direction finding receiver for UWB impulse radio signal in multipath environment

In this paper, we propose a direction finding (DF) receiver for ultra wideband impulse radio (UWB‐IR) signal in a realistic multipath environment. The receiver uses an array of antenna, where each antenna is connected to a proposed propagation‐delay estimation structure. The advantage of the proposed structure is that it outputs a trapezoidal signal whose amplitude reflects the propagation delay and thus relaxes the sampling rate requirement of the analog‐to‐digital‐converter (ADC). The angle‐of‐arrival (AOA) is estimated from the vector of propagation delays measured with respect to reference antenna. Because these estimated delays contain outliers, we propose a simple AOA estimation algorithm based on minimum fractional‐distance search. Experimental results based on simulation show that the proposed DF receiver achieves better performance compared with the minimum ?₁‐ and ?₂‐based (least‐squares based) distance search. Copyright © 2010 John Wiley & Sons, Ltd.     

Performance analysis for impulse radio and direct-sequence impulse radio in narrowband interference

The impact of narrowband interference (NBI) on two ultra wideband (UWB) systems is analyzed. The two systems are impulse radio (IR) and a variation of it, termed direct-sequence IR (DS-IR). The signal-to-noise ratio (SNR) at the decision device of a correlation receiver is computed for both systems, assuming that the NBI is wide sense stationary and that the channel is frequency-selective. The SNR is expressed by means of a simple equation involving the signal and the interference spectrum. Next, a statistical model for the interference is introduced, considering the interference as the sum of a given number of sinusoidal signals with random powers and frequencies. The bit-error rate of IR and DS-IR is derived. The results are then specialized and compared with simulations in three case studies of practical interest, where the NBI is a single jammer with deterministic power and frequency, a multitone signal with random frequencies, or a grid of interfering signals with random powers.     

短波广播信号的特征及其监测技术的研究

简要介绍了短波广播信号的优势及短波广播频段的使用现状,说明了短波广播信号的普遍特征,重点提出了短波广播信号的监测方法以及联合测向方法.通过多辆移动监测车配合固定站进行联合测向定位,很好地解决了短波无线电测向的盲区问题,再通过将测量结果与短波广播台站数据库进行比对,进一步验证了该方法的可行性.     

Performance analysis and optimization for impulse radio and direct-sequence impulse radio in multiuser interference

The performance of two ultra wideband communication systems is investigated. The first system is the classical impulse radio (IR). The second is obtained by adding a direct-sequence (DS) code to the IR system, and is termed direct-sequence impulse radio (DS-IR). For both systems, binary pulse amplitude modulation is considered. The performance of IR and DS-IR is analyzed in a multiuser scenario, assuming an ideal channel and a correlation receiver. The performance analysis is original and general. It yields simple and exact formulas relating the performance to the system parameters. The analysis shows that IR suffers a performance degradation with respect to DS-IR unless the system parameters are chosen carefully. An optimum shape for the monocycle is identified, yielding an upper bound to the performance. The optimum system achieving this upper bound is shown to be, in principle, feasible for both DS-IR and IR. The degradation experienced by real systems with respect to the optimum system is also evaluated. Furthermore, it is shown that DS-IR has practical advantages with respect to IR. Simulations are included to validate the theoretical findings.     

Broadband RF stage architecture for software-defined radio inhandheld terminal applications

Broadband RF is a general-purpose common RF stage for every standard within a set of RF bands. The RF stage architecture presented in this article is suitable for software-defined radios. This article first defines the conceptual scheme of a handheld software defined radio (SDR) terminal, and then describes how the direct conversion principle is applied to the SDR. The discussion focuses on receiver hardware implementation and systematic control     

Ring sensor and heart rate monitoring system for sensor network applications

A ring-type pulse oximeter sensor attached to the finger and its 24-hour ambulatory heart rate monitoring system are presented. The PCB has been designed with a light-to-frequency converter and the CPU with a built-in Zigbee stack for simple and low power consumption. Also designed is the algorithm using a least square estimator to calibrate various signal distortions caused by motion artefacts for a proper accuracy.     

A general-purpose signal processor architecture for neurocomputing and preprocessing applications

A general-purpose Neural Signal Processor MA16 is presented the architecure of which is guided by an analysis of today's neural algorithms. The MA16 executes the elementary algorithmic strings which are compute-bound and shared by all neural nets; operations which are not time consuming are let to hardware off-the-shelf. Digital design is chosen because of flexibility and computation accuracy. The throughput is 800 million connections per second at a clock frequency of 50 MHz (1 connection = 16 bit). This performance is valid for arbitrary networks provided they consist of more than 16 neurons each comprising more than 16 synapses. Depending on the needs of the application under consideration a linear or 2-dimensional array of VLSI chips can be constructed in order to provide sufficient processing power and weight memory.     

无线电信号自动监听系统的设计

介绍了一种无线电信号自动监听系统的系统组成、基本功能、工作方式及多频点扫描监听方式下设计时需要注意的问题.     

可编程信号处理器的低功耗设计

可编程信号处理器已获得广泛应用，随着VLSI技术的发展，现在已可利用信号处理器实现SOC功能，实现SOC功能还必须降低处理器的功耗。本文首先叙述可编程信号处理器降低功耗的各种途径，然后介绍低功耗可编程处理器的结构设计，最后对最新的TMS320C55X的低功耗性能进行分析。     

A VLSI architecture for a high-speed all-digital quadraturemodulator and demodulator for digital radio applications

An all-digital architecture is presented for implementing the front-end signal-processing functions in a quadrature modulator and demodulator for high bit-rate digital radio applications. A pair of CMOS chips has been designed and submitted for fabrication in a 1.25-μm process and is expected to accommodate symbol rates up to 35 MBd. The modulator chip accepts a pair of 8-b in-phase and quadrature data streams and generates a bandlimited IF output with an excess bandwidth factor of 35%. The demodulator chip accepts a digitized IF input signal and generates a pair of filtered in-phase and quadrature baseband signals. The modulator and demodulator chips each incorporate 40-tap multiplierless FIR (finite-impulse response) square-root Nyquist matched filters, and the cascade of the two chips achieves a peak intersymbol interference distortion of -54 dB. The modulator chip can generate any arbitrary signal constellation within a rectangular grid of 256×256 points. Thus, the all-digital implementation results in a generic chip set suitable for a wide variety of high bit-rate digital modem designs using formats such as M-ary PSK and QAM     

Photonic sensor with radio frequency power detection for body pressure monitoring

A photonic sensor with radio frequency(RF) power detection for body pressure monitoring is proposed. The sensor based on two fiber Bragg gratings(FBGs) can transfer the wavelength shift to the change of RF power. The pressure can be measured by modulating and processing one single frequency RF signal. The theoretical analysis and experimental results of the photonic sensor are presented and discussed. The pressure sensitivities are acquired with 2.62×10^-5 mW/kPa at 2.14 GHz, 2.46×10     

广播电台信号系统发射监控技术问题分析

随着现代科学技术的突飞猛进,伴随着广播电台信号系统的相关技术也得到了很大程度的发展.但是由于我国的广播电台发展的相对较晚,在其法制等相关建设上,不够全面,对其的监控在技术和体制上也相对的不完善.广播电台的信号发射系统监控跟国家的信息安全有着很大的关系.     

Low-power and high-speed ROM modules for ASIC applications

We describe in this paper the design of a set of low-power and high-speed NOR-type ROM modules suitable for embedded applications in ASICs or SOCs. The circuit is derived from the four-phase high-speed precharge-discharge dynamic CMOS logic (NHS-PDCMOS) with the number of operational phases reduced from four to one. This facilitates the interconnections to other system blocks that are usually designed to be one phase. Experimental results show that for the size of 2K×8, the proposed high-speed ROM module is about 1.89 times faster, consumes 21% less power, and occupies similar silicon area as compared to a conventional design. Also for the same size, the proposed low-power ROM module is 1.17 times faster, 14% smaller, and consumes 83% less power as compared to the conventional design     

A sensor monitoring system for telemedicine,safety and security applications

A sensor system capable of medical, safety and security monitoring in avionic and other environments (e.g. homes) is examined. For application inside an aircraft cabin, the system relies on an optical cellular network that connects each seat to a server and uses a set of database applications to process data related to passengers’ health, safety and security status. Health monitoring typically encompasses electrocardiogram, pulse oximetry and blood pressure, body temperature and respiration rate while safety and security monitoring is related to the standard flight attendance duties, such as cabin preparation for take-off, landing, flight in regions of turbulence, etc. In contrast to previous related works, this article focuses on the system’s modules (medical and safety sensors and associated hardware), the database applications used for the overall control of the monitoring function and the potential use of the system for security applications. Further tests involving medical, safety and security sensing performed in an real A340 mock-up set-up are also described and reference is made to the possible use of the sensing system in alternative environments and applications, such as health monitoring within other means of transport (e.g. trains or small passenger sea vessels) as well as for remotely located home users, over a wired Ethernet network or the Internet.     

互调信号特性分析及解决方法

由于台站共址或位置相近、个别监测设备周围电磁环境复杂、个别无线电台站外部金属器件老化等原因,在无线电监测工作中,互调信号一直是一个无法回避的问题,在频段扫描、占用度测试、干扰源测向定位、信号分析与识别等监测工作中,均会对测量结果产生影响.如何准确认识互调干扰信号.并在无线电监测系统中采用系统、灵活的方案对其进行准确分析和识别,是无线电监测工作者必须重视的问题.     

无线传感器网络信号突变监控模块的电路设计

传统的无线电监测系统主要通过单站监测的方法对信号突变进行监测,但不能对复杂的高频宽带无线电信号突变进行准确监测。因此,设计无线传感网络信号突变监控模块的实现电路,其由高频激发器、窄带滤波器、程控放大器、A/D采集电路、FPGA和主控制器等构成。编制开发无线传感网络信号突变监控模块的上位机控制软件,并向下位机主控器传递控制指令,确保各电路模块协作完成无线信号突变的监控。实验结果表明,所设计监控模块的电路,可对无线传感网络信号突变情况进行准确、高效率的监控。