摘要:心脏，在人体的血液循环系统中起着核心作用，是重要的动力器官。它承担着血液运输的功能。然而，随着生活节奏的日益加快，过重的压力，不健康的生活、饮食习惯等都给心脏带来了负荷。据了解，心血管疾病严重地威胁了人们的生命，对此类疾病的防治已成为医学上的重、难点问题。因而能够准确获取和即时检测人体的心电信号具有重要的意义。便携式心电仪就是一种方便人们随身携带，有助于提早对心血管疾病做出预警的电子设备。

　　　心电信号频率极低，一般在0.05~100Hz之间。同时它的微弱性使得其十分容易受到其他信号的干扰。心电信号幅度大约为10μV~5mV。在对采集到的心电信号进行放大之后，需要将低通和高通滤波器串联起来组成带通滤波器，接着对干扰信号进行滤除，同时使用陷波器对50Hz的工频干扰作进一步滤除，从而得到失真度小且高质量的心电信号。最后利用带有A/D转换功能的STC系列51单片机将最终结果显示在液晶屏上。

　　　本论文针对人体心电信号的特点，设计了一种简易实用、性能稳定的便携式心电仪。无论是在室内还是户外都能够对心电信号进行实时监测，应用前景相当广阔。

关键词 心电信号；便携式；心电仪；STC12C5410AD

Abstract:The heart, in the body's blood circulation system, is an important power organ which plays a central role. It assumes the function of blood transportation. However, with the accelerated pace of life, too much stress, unhealthy life, eating habits brought heart load. Learned, cardiovascular diseases seriously threaten the lives of people. To prevent and control this kind of disease has become a heavy and difficult problem in medical. Thus obtaining the accurate and real-time detection of the human body has the vital significance of ECG signals. Portable heart is one kind of device which can be portable and help warn cardiovascular disease early. 

　　　The frequency of ECG signal is very small, generally between 0.05 ~ 100 Hz. The weakness of the signal at the same time makes it very vulnerable to the interference of other signals. Amplitude of ECG signal is approximately 10μV ~ 5 mV. After amplifying the collected ECG signal, we need to group a low-pass and high-pass filter together. They form a band-pass filter, and then it begins to filter the interference signal. At the same time, we use the trap on the interference of 50 Hz frequency for further filtering. Thus pure and high quality of the ECG signal is obtained. Finally we use the function of A/D conversion on STC12C5410AD. Then the result will display on the LCD screen. 

　  According to the characteristics of human’s ECG signal, this paper designs a simple and practical, reliable, portable heart instrument. In the indoor and outdoor place we can monitor ECG signal all the times. It has a certain development prospects.

Keywords   ECG signal   portable   electrocardiogram equipment   STC12C5410AD

　　　本论文基于51单片机，设计了一款简易的便携式心电仪。根据心电信号的特点，设定了一系列的放大滤波电路，包括前置放大电路、后级放大、带通滤波和帯阻滤波。在查阅了大量的资料之后，弄清了硬件设计的原理，终于完成了硬件的制作。

　　　经过多次调试，基本能够显示出稳定的心电图波形。在器件的选择上，尽量保证较高的性价比，保证波形尽可能的不失真。此次单片机的选择上也颇有创新，选择了一款带有AD转换功能的单片机，实现了系统最小化，便捷化。

当然设计还有相当多的不足之处。所设计的心电仪原定有报警装置，即当心率超过一定正常值时，系统将发出报警。多次尝试失败后，在控制电路板上焊上了一个LED指示灯，用来指示心跳的频率，根据输出信号的大小呈现明暗闪烁。最终设计的成品只实现了显示人体心跳的波形图，当有信号时，呈现心跳式的抖动，无信号输入则呈现满格状态。