适用于检测生理信号的高精度光隔离数据转换卡

作者针对目前常见数据转换卡对低频小信号传输性能较差的缺陷，介绍了一种适用于检测生理信号，可与ＰＣ机及其兼容机直接接口，带光隔离脉冲调制电路的高精度数据转换卡。简述其原理、构成及应用。电路具有七路输入选通１２位Ａ／Ｄ转换及两路８位Ｄ／Ａ输出，采用高频脉冲调制技术，实现了对多路模拟低频或直接生理小信号的光电传输，能够满足智能化医疗仪器中对各种生理信号测量、分析、诊断的需要，该转换卡使用方便、通用性强，     

8098单片机生理信号实时记录系统

本文介绍了一种８０９８单片机生理信号实时记录系统的软、硬件结构。８０９８单片机片内１０位Ａ／Ｄ转换器将生理信号数字化，采样频率在１００Ｈｚ－１０ＫＨｚ范围内可调。系统软件采用ＰＬ／Ｍ－９６高效率结构化高级语言编写。系统可按要求对生理信号进行实时显示，冻结、幅度测量，生理信号用示波器屏幕显示，测量值以浮点数形式在ＬＥＤ显示器上显示。最后结果由ＰＰ４０打印机输出。     

一种低功耗微弱生理信号检测系统的设计

目的电生理信号可以提供人体各种生理状态的重要信息,它常常需要长时间的监测,因此要求检测系统具有低功耗特性。本文设计一种基于MSP430F5438处理器的微弱生理信号检测系统,并重点关注其功耗、可靠性和测量精度。方法系统包括高性能模拟放大前端、低功耗下位机和对上传的信号进行多种处理的PC机。下位机采用MSP430F5438单片机,它具有功耗低、体积小优点,它移植有UCOS＆UCGUI系统,方便储存和处理数据。PC机可以通过USB方便地连接下位机并处理数据。结果系统可开发成电池供电的便携式检测储存装置,其特色是低功耗和便携性,这有助于长时间检测电生理信号。结论微弱生理信号检测与处理作为一个系统工程,在医疗保健和研究方面有广大的应用前景。     

Weak physiological signal detection system with low power consumption

目的电生理信号可以提供人体各种生理状态的重要信息,它常常需要长时间的监测,因此要求检测系统具有低功耗特性.本文设计一种基于MSP430F5438处理器的微弱生理信号检测系统,并重点关注其功耗、可靠性和测量精度.方法 系统包括高性能模拟放大前端、低功耗下位机和对上传的信号进行多种处理的PC机.下位机采用MSP430F5438单片机,它具有功耗低、体积小优点,它移植有UCOS&UCGUI系统,方便储存和处理数据.PC机可以通过USB方便地连接下位机并处理数据.结果 系统可开发成电池供电的便携式检测储存装置,其特色是低功耗和便携性,这有助于长时间检测电生理信号.结论 微弱生理信号检测与处理作为一个系统工程,在医疗保健和研究方面有广大的应用前景.     

双道高精度数控医用信号仪的研制

目的:研制出一种以单片机和高性能芯片为核心研制的医用信号仪。方法:主要利用单片机控制两片高精度数控频率和位相的IC(AD9833)和D/A转换IC(AD558)等,并利用LCD显示信号的相关参数。结果:该仪器可输出双道高精度频率和位相的正弦、三角、方波信号及各种生理信号。可用于人耳频率特性和人体阻抗特性的研究和教学;利用同时输出的两道位相差可数控的正弦信号,可方便地演示医学物理等教学中两简谐振动在不同频率、不同相位差、不同方向等情况下的合成,如拍频、李萨如图形等。结论:该智能仪器可广泛用于实验教学、临床测试和医疗仪器维修。     

基于STM32和USB接口的开放式高性能新型医用信号仪的研制

为满足研究各种细胞、组织等的电生物效应所需的高精度特殊刺激信号,以及科研、教学和医学仪器的调试和维修等需求,研制以内带D/A转换、A/D转换、USB引擎的高性价比、32位单片机STM32F103RD和高性能单频信号发生芯片AD9833为核心的开放式高性能医用信号仪。该仪器能同时输出两路生理信号(如心电波、脉搏波、呼吸波)和特殊波形信号、高频率精度和位相差精度的常用信号(如正弦、三角波和方波)或一路特殊信号和一路常用信号,输出电压幅度可达10 V,电流最大可达350 mA,最高频率可达12 MHz。该仪器具有开放性好、体积小、性能稳定、操作简便,显示直观等优点,可广泛用于电生物效应和医学其它科研、实验教学和医学仪器的调试和维修等。     

下颌运动描记装置简介

口－颌系统的功能，如咀嚼、吞咽等是通过下颌运动来完成的，因此对下颌运动进行分析可判明口－颌系统生理或病理状况、对口腔医学诊断具有重要意义。设计一个描记下颌运动的系统，本系统通过电磁转换将下颌运动的变化转化为三路电信号的输出。用ＭＣＳ－５１系列单片机８０３１进行信号采集、转换、数据处理及在示波器上显示其运动在不同平面的投影。     

心血管系统实验室中生理信号的计算机分析方法

本文介绍了一个心血管动物实验中对信号进行数据采集和分析的综合性计算机程序,可在IBM-PC/XT/AT等兼容机上运行。整个系统由微型计算机加AD转换及其它支持模块构成,可以对8道心血管生理信号进行采样、量化、滤波及微分处理,并可对输入的瞬时及平均信号进行检测、分析和绘图输出。系统程序可以自动测量每一心动周期及平均心动周期信号     

一种无创脉搏波检测分析系统的研制

研制了一套无创脉搏信号检测分析系统，系统采用生理压力传感器同时采集两路脉搏波信号，实现了脉搏波信号的实时采集、存储、动态显示、波形波速度分析和诊断报告的打印，能够较全面的评价心血管系统的功能。该系统采用单片机与计算机结合的设计方式，同时具有单片机小型化、便携的特点和计算机强大的数据存储、分析、处理的能力。初步临床实验表明，该系统操作方便，稳定性好，检测的可重复性较好。     

AT89C2051单片机A＼D串行数据采集系统

1　引言在计算机控制系统中 ,通常设有模拟量输入通道 ,必须将模拟量转化为数字量才能送入计算机 ,进行进一步的处理。这里 A/ D转换芯片起着极其重要的作用。随着计算机使用范围的扩大 ,串行 A/ D转换芯片获得了广泛的应用。再之 ,由于美国 ATMEL公司生产的 AT89C2 0 5 1单片机的本身性能 ,利用串行 A/ D芯片可以极方便的构成数据采集系统。因此 ,MAX176已成为广大使用者的首选芯片。也使得系统具有结构简单、性能价格比高的特点。2　 AT89C2 0 5 1与 MAX176芯片介绍AT89C2 0 5 1是一种高效的微控制器 ,其主要性能是 1具有 15条…     

Assessment of noise in a digital image using the join-count statistic and the Moran test.

We assume that the data bits of a pixel in digital images can be divided into signal and noise bits. The signal bits occupy the most significant part of the pixel and the noise bits the least significant part. The signal part of each pixel are correlated while the noise parts are uncorrelated. Two statistical methods, the Moran test and the join-count statistic, are used to examine the noise parts. Images from three digital modalities--computerized tomography, magnetic resonance and computed radiography--are used for the evaluation of the noise bits. A residual image is formed by subtracting the original image from its smoothed version. The noise level in the residual image is then identical to that in the original image. Both statistical tests are then performed on the bit planes of the residual image. The results show that most digital images contain only 8-9 bits of correlated information. Both methods are easy to implement and fast to perform.     

Real-time compression of myoelectric data utilising adaptive differential pulse code modulation

The myoelectric signal, obtained by either surface or needle electrodes, is used in many areas of clinical research and diagnosis. The conventional method of storing such information is in digitised form on a computer. However, the bandwidth of the signal and the required resolution result in large memory requirements. Adaptive differential pulse code modulation is investigated as a method of reducing the memory requirements for myoelectric data storage. In this scheme, a 12-bit sample is reduced to four bits, thus reducing the memory requirements by a factor of three. In reality, this compression ratio is closer to 4∶1 owing to the fact that the widths of most memories are organised as multiples of eight bits.     

基于ARM7的新型开放式多功能医用信号仪的研制

目的现有的常用信号发生器或生理信号发生器不能同时输出常用信号和模拟生理信号,本文提出一种新型开放式多功能医用信号仪,用于检测各种生理信号,听取不同频率、不同信号的声音及输出常用信号等。方法该仪器以STM32F103RF和高性能集成芯片MAX038为核心。此医用信号仪包括硬件和软件两部分,其中硬件含有ARM7单片机控制单元、按钮组输入单元、数据存储单元等12个单元,软件用C语言编写,并采用keil C进行编译。结果该仪器不仅能输出常用的正弦、方波、三角波、锯齿、矩形信号,还能输出医学中常用的多种生理信号如心电、脉搏波等,且信号波形频率、幅度、类型、波形均采用直观的LCD液晶显示。此外,该仪器具有一个高驱动能力的接口,可直接驱动耳机等,以方便对人耳频率特性和人体阻抗特性的研究和教学。同时,为了便于使用一般示波器能观察各种生理信号,对同一种生理信号可输出不同的频率。结论本仪器使用方便,可广泛应用于科研、教学、测试和仪器维修等。     

Investigation of basic imaging properties in digital radiography. 9. Effect of displayed grey levels on signal detection

Results of an 18-alternative forced-choice experiment have shown that observers were capable of detecting a signal with a contrast of 1 in terms of 10-bit data which were displayed on a CRT monitor with an 8-bit video generator and a window width setting of 1024. We investigated the conditions under which 10-bit signal data can be detected when displayed using an 8-bit video generator. Results show that the 10-bit digital quantum noise, which was approximately Gaussian distributed, can act as a carrier of the signal data, thus allowing a signal having a contrast of a fraction of a displayed grey level to be detected. We demonstrate the relationship between the rms value of the digital noise (obtainable with a clinical digital subtraction angiography system under various exposure levels), the number of bits available in the display video generator, and the "transmitted" signal contrast displayed on the CRT monitor.     

Quick method of measuring the furrows distribution on skin surface replicas

A fast method of measuring the distribution of furrows can be obtained via the analysis of TV camera images of skin replicas. These replicas are either negative (or direct) or positive. Reflected or transmitted light is used, depending on the type of replica. Each point of the matrix (256×256 pixels) is digitised over 6 bits (64 levels) and treated by a personal computer (IBM AT or PC). With such an image, it is not possible to obtain significant results without eliminating noise and enhancing the furrows. Specific software is written in processor language 8086 to obtain a real time system. The distribution of skin furrows is quantified for several interesting cases such as the ageing of the skin or the effect of stress.     

开放式生理信号产生及测量仪的研制

我们提出了一种以单片机为核心研制的开放式生理信号的产生及测量仪。该仪器使用液晶LCD显示信号波形和相关参数信息以及键盘实现人机交互 ,并采用存储常用波形的特征数据及相应的算法来产生所拟定的信号 (多种生理信号和常用信号 ) ,同时也可产生用户自定的信号 ,具有较好的开放性。另外 ,采用与计算机类似的模块设计方法 ,使其具有很好的扩展性。本仪器不仅具有显示、测量和保存生理信号等功能 ,而且还具有功耗低、体积小、成本低、携带方便等特点 ,因此该智能仪器在实验教学、临床测试和医疗仪器维修中使用方便。     

Emotion processing in three systems: the medium and the message.

In the context of picture viewing, consistent and specific relationships have been found between two emotion dimensions (valence and arousal) and self-report, physiological and overt behavioral responses. Relationships between stimulus content and the emotion-response profile can also be modulated by the formal properties of stimulus presentation such as screen size. The present experiment explored the impact of another presentation attribute, stimulus motion, on the perceived quality of the induced emotion and on its associated physiological response pattern. Using a within-subject design, moving and still versions of emotion-eliciting stimuli were shown to 35 subjects while facial muscle, heart rate, skin conductance, and emotion self-reports were monitored. The impact of motion was dramatic. Self-report and physiological data suggested strongly that motion increased arousal, had little impact on valence, and captured and sustained the subject's attention to the image.     

Nitric oxide: a physiological mediator of the type 2 (AT2) angiotensin receptor

Virtually all of the biological actions of angiotensin II (ANG II) have been thought to be mediated by the type 1 (AT1) angiotensin receptor and the function of the type 2 (AT2) receptor is unknown. We now describe a novel physiological action of ANG II to release nitric oxide (NO) mediated by the AT2 receptor in both the kidney and gastrointestinal tract. We present an integrated model for a counter-regulatory protective action of the AT2 receptor mediated by nitric oxide. In the kidney, ANG II at the AT2 receptor stimulates a vasodilator cascade of bradykinin (BK), NO and cyclic GMP which is tonically activated only during conditions of increased ANG II, such as sodium depletion. In the absence of the AT2 receptor, pressor and antinatriuretic hypersensitivity to ANG II is associated with BK and NO deficiency. In angiotensin-dependent hypertension, the hypotensive effect at AT1 receptor blockade is due at least in part to AT2 receptor stimulation and consequent increased activity of the vasodilator cascade. In the gastrointestinal tract, physiological quantities of ANG II stimulate the AT2 receptor releasing NO and cGMP leading to increased sodium and water absorption. In conclusion, NO is an important physiological mediator of ANG II at the AT2 receptor.     

The angiotensin II AT1 receptor structure-activity correlations in the light of rhodopsin structure

The most prevalent physiological effects of ANG II, the main product of the renin-angiotensin system, are mediated by the AT1 receptor, a rhodopsin-like AGPCR. Numerous studies of the cardiovascular effects of synthetic peptide analogs allowed a detailed mapping of ANG II's structural requirements for receptor binding and activation, which were complemented by site-directed mutagenesis studies on the AT1 receptor to investigate the role of its structure in ligand binding, signal transduction, phosphorylation, binding to arrestins, internalization, desensitization, tachyphylaxis, and other properties. The knowledge of the high-resolution structure of rhodopsin allowed homology modeling of the AT1 receptor. The models thus built and mutagenesis data indicate that physiological (agonist binding) or constitutive (mutated receptor) activation may involve different degrees of expansion of the receptor's central cavity. Residues in ANG II structure seem to control these conformational changes and to dictate the type of cytosolic event elicited during the activation. 1) Agonist aromatic residues (Phe8 and Tyr4) favor the coupling to G protein, and 2) absence of these residues can favor a mechanism leading directly to receptor internalization via phosphorylation by specific kinases of the receptor's COOH-terminal Ser and Thr residues, arrestin binding, and clathrin-dependent coated-pit vesicles. On the other hand, the NH2-terminal residues of the agonists ANG II and [Sar1]-ANG II were found to bind by two distinct modes to the AT1 receptor extracellular site flanked by the COOH-terminal segments of the EC-3 loop and the NH2-terminal domain. Since the [Sar1]-ligand is the most potent molecule to trigger tachyphylaxis in AT1 receptors, it was suggested that its corresponding binding mode might be associated with this special condition of receptors.     

Influence of lossy compression on eye movement signals

Eye movements considered in our research are physiological signals that are measured in otoneurological balance tests. They are also investigated in other areas of medicine and in psychology. When great amounts of signals are measured in clinical and research work, signal compression is of great use in storing measurements for later investigations. In this research we assessed the influence of lossy compression on medically interesting parameter values that are computed from eye movement signals. We found that high compression ratios with bit rates lower than 1.5 bits per sample on signals with an original resolution of 13 bits per sample produced results without significant changes to the medical parameters values.