便携式数字血压计中英文对照外文翻译文献.docx

1、便携式数字血压计中英文对照外文翻译文献中英文资料对照外文翻译便携式数字血压计产品简介我们的最后一个项目是设计和建立一个便携式血压监测装置，可以通过一个充气袖口测量一个人的血压和心率。该装置包括三个主要部分：外部硬件（如袖口，电机，阀门，和液晶显示器）、模拟电路与单片机。模拟电路转换的袖带内的压力值形成可读和可使用的模拟波形。单片机对样本波形并进行模数转换，可以做进一步计算。此外，单片机用按钮控制操作设备、液晶显示。因为我们有这个词便携式的称号，用一个包就可以装下，允许用户把它带到任何地方，无论何时何地进行测量。不可否认的是，现在人们更多地关注健康状况。其中最广泛使用的测试健康状况的方法是衡量一

2、个人的血压和心率。为了人们的健康，我们决定为解决这一问题而设计一个在现实生活中有益的和可用的设备。高层次的设计1）血压测量通常当医生测量病人的血压时给袖口充气，并使用听诊器听血液在病人的手臂动脉的声音。开始时，空气被输送到收缩压值以上。在这一点上，医生什么也听不到，随着压力渐渐地被释放，在某一点上，医生会开始听到心脏跳动的声音，这一点对应的是收缩压的值。压力进一步降低后，医生将继续听到的声音（与之前声音不同）。并在某一点，声音将开始消失，这一点对应舒张压的值。 我们使用的这种测量方法叫“示波法”。空气将被冲入袖口20毫米汞柱左右，高于平均收缩压（平均约120毫米汞柱）。之后，空气会慢慢从袖口放

3、出，导致在袖口的压力慢慢减小，我们将测量在手臂袖口气压的微小振荡，收缩压是压力脉动开始出现时，我们将使用单片机检测该点，然后记录该压力值。然后在袖口的压力将进一步减少。舒张压将采取点振荡开始消失时的点3）硬件框图上面的图显示了我们的设备是如何运作的。用户将使用按钮来控制操作整个系统。单片机的主要成分是控制所有操作，如电机和阀门控制，A / D转换和计算，直到测量完成。然后是通过液晶屏输出结果供用户观察。4）模拟电路模拟电路用于放大压力传感器的输出信号的直流和交流成分，我们可以使用单片机来处理信号，并获得有用的信息。压力传感器的生产应用的差分输入压力和输出电压成正比。输出电压压力传感器，范围从0

4、到40毫伏。但我们的应用希望泵手臂袖口只有160毫米汞柱（约21.33千帕），这相当于约18 mV的输出电压。因此，我们选择放大电压，直流放大器的直流输出电压输出范围从0至4V。因此，我们需要的增益约为200。然后直流放大器的信号将传递到带通滤波器，直流放大器放大直流和交流信号的组成部分（它只是一个普通的放大器）。过滤器的设计有较大的增益在1-4赫兹左右，使通带任何信号衰减，是带通滤波器的交流分量最重要的因素，以确定何时捕获的收缩压/舒张压时以确定心脏使用率。最后一个阶段是交流耦合阶段，我们使用两个相同的电阻提供直流约2.5伏特的偏置电压。使用47 uF的电容耦合只有交流信号的组成部分，使我们

5、能够独立的提供直流偏置电压。硬件设计1）压力传感器我们使用来自摩托罗拉MPX2050压力传感器接受手臂袖口压力。压力传感器应用的差分输入压力和输出电压成正比。我们连接管输入袖口和我们离开打开另一个输入，通过这种方式，将是成正比的输出电压区别在袖口的压力和在房间里的空气压力。传输特性如图图1：输出电压和差分输入压力2）直流放大器由于压力传感器的输出电压是非常小的，我们必须作进一步的信号放大处理。我们使用ADI公司的仪表放大器AD620。电阻R G是用来确定放大器的增益。因为我们需要大约200的增益，我们选择电阻R G是240欧姆。这将使我们根据公式的增益。然而，我们已经测量从成品电路，测得的增益

6、是213。放大器的电路图如图2所示。图2：直流放大器的电路图3）带通滤波器作为一个活跃的两个带通滤波器级联设计的带通滤波器阶段。之所以使用两个带通阶段将提供一个比仅使用单级更大的增益和频率响应的滤波器将具有清晰的切断。这种方法将提高输出噪声比。“两个滤波器的原理图如图3所示。图3：带通滤波器阶段第一个带通滤波器：低频截止高频率截止第一个过滤器的中频增益第二带通滤波器：低频截止高频率截止第一个过滤器的中频增益因此，对带通滤波器阶段，总增益为399.6。结合这一增益与增益从直流放大器，总交流电路增益为，选择高和低截止频率足够好给我们非常干净的交流波形。4）交流耦合级交流耦合阶段是用来提供直流偏置水

7、平。我们要的直流电平波形定位大约一半，这是2.5伏交流耦合阶段示意图如图4所示。鉴于这种偏执电流，这是我们更容易使用单片机上模数转换器的微控制器处理交流信号。图4：交流耦合级直流偏压这个阶段的交流输出将通过在Mega32单片机的模拟 - 数字转换器。实验室的示波器上的图像如图5所示。我们可以看到波形非常漂亮和干净。图5：交流波形附录5 英文原文Portable Digital Blood Pressure MonitorIntroductionOur final project is to design and build a portable blood pressure monitor d

8、evice that can measure a users blood pressures and heart rate through an inflatable hand cuff. The device is consisted of three main parts: external hard wares (such as cuff, motor, valve, and lcd), analog circuit, and microcontroller. The analog circuit converts the pressure value inside the cuff i

9、nto readable and usable analog waveforms. The MCU samples the waveforms and performs A/D convention so that further calculations can be made. In addition, the MCU also controls the operation of the devices such as the button and lcd display. Since we have the word portable in our title, for sure all

10、 of the components are put together in one package which allows a user to take it anywhere and perform a measurement whenever and wherever he/she wants.It is undeniable that nowadays people are more aware of the health conditions. One of the most widely used methods to test the health conditions of

11、an individual is to measure his/her blood pressures and heart rate. We, as ones of those who are concerned about their health, decided to work on this subject matter because we would like to build something that is useful and useable in real life.High Level Design1) How blood pressures are measuredU

12、sually when the doctor measures the patients blood pressure, he will pump the air into the cuff and use the stethoscope to listen to the sounds of the blood in the artery of the patients arm. At the start, the air is pumped to be above the systolic value. At this point, the doctor will hear nothing

13、through the stethoscope. After the pressure is released gradually, at some point, the doctor will begin to hear the sound of the heart beats. At this point, the pressure in the cuff corresponds to the systolic pressure. After the pressure decreases further, the doctor will continue hearing the sound

14、 (with different characteristics). And at some point, the sounds will begin to disappear. At this point, the pressure in the cuff corresponds to the diastolic pressure.To perform a measurement, we use a method called “oscillometric”. The air will be pumped into the cuff to be around 20 mmHg above av

15、erage systolic pressure (about 120 mmHg for an average). After that the air will be slowly released from the cuff causing the pressure in the cuff to decrease. As the cuff is slowly deflated, we will be measuring the tiny oscillation in the air pressure of the arm cuff. The systolic pressure will be

16、 the pressure at which the pulsation starts to occur. We will use the MCU to detect the point at which this oscillation happens and then record the pressure in the cuff. Then the pressure in the cuff will decrease further. The diastolic pressure will be taken at the point in which the oscillation st

17、arts to disappear.3) Hardware diagramThe diagram above shows how our device is operated. The user will use buttons to control the operations of the whole system. The MCU is the main component that controls all the operations such as motor and valve control, A/D conversion, and calculation, until the

18、 measurement is completed. The results then are output through and LCD screen for the user to see.4) Analog CircuitThe analog circuit is used to amplify both the DC and AC components of the output signal of pressure transducer so that we can use the MCU to process the signal and obtain useful inform

19、ation about the health of the user. The pressure transducer produces the output voltage proportional to the applied differential input pressure. The output voltage of the pressure transducer ranges from 0 to 40 mV. But for our application, we want to pump the arm cuff to only 160 mmHg (Approximately

20、21.33kPa). This corresponds to the output voltage of approximately 18 mV. Thus, we choose to amplify the voltage so that the DC output voltage of DC amplifier has an output range from 0 to 4V. Thus, we need a gain of approximately 200. Then the signal from the DC amplifier will be passed on to the b

21、and-pass filter. The DC amplifier amplifies both DC and AC component of the signal (its just a regular amplifier). The filter is designed to have large gain at around 1-4 Hz and to attenuate any signal that is out of the pass band. The AC component from the band-pass filter is the most important fac

22、tor to determine when to capture the systolic/diastolic pressures and when to determine the heart rate of the user. The final stage is the AC coupling stage. We use two identical resistors to provide a DC bias level at approximately 2.5 volts. The 47 uF capacitor is used to coupling only AC componen

23、t of the signal so that we can provide the DC bias level independently.Hardware Design1) Pressure TransducerWe use the MPX2050 pressure transducer from Motorola to sense the pressure from the arm cuff. The pressure transducer produces the output voltage proportional to the applied differential input

24、 pressure. We connect the tube from the cuff to one of the inputs and we leave another input open. By this way, the output voltage will be proportional to the difference between the pressure in the cuff and the air pressure in the room. The transfer characteristic is shown in figure 1.Figure 1: Outp

25、ut voltage vs. Differential input pressure2) DC AmplifierSince the output voltage of the pressure transducer is very small, we have to amplify the signal for further processing. We use the instrumentation amplifier AD620 from Analog Devices. The resistor R G is used to determine the gain of the ampl

26、ifier according to the equation Rg=49.4k/（G-1). Since we need the gain of approximately 200, we choose the resistor R G to be 240 ohms. This will give us the gain of 206 according to the equation. However, we have measured the gain from the finished circuit, and the measured gain is 213. The schemat

27、ic of the amplifier is shown in figure 2.Figure 2: Schematic of DC amplifier3) Band-pass FilterThe band-pass filter stage is designed as a cascade of the two active band-pass filters. The reason for using two stages is that the overall band-pass stage would provide a large gain and the frequency res

28、ponse of the filter will have sharper cut off than using only single stage. This method will improve the signal to noise ratio of the output. The schematics for both filters are shown in figure 3.Figure 3: Band passes Filter StageFirst Band-pass filter: The lower frequency cutoff isThe higher freque

29、ncy cutoff isThe mid-band gain of the first filter isSecond Band-pass filter:The lower frequency cutoff isThe higher frequency cutoff isThe mid-band gain of the first filter isThus for the band-pass filter stage, the overall gain is 399.6. Combining this gain with the gain from the DC amplifier, the

30、 total AC gain for the circuit is .The choice of high and low cut-off frequency is good enough to give us very clean AC waveform.4) AC coupling stageThe ac coupling stage is used to provide the DC bias level. We want the DC level of the waveform to locate at approximately half Vdd, which is 2.5 V. T

31、he schematic for AC coupling stage is shown in figure 4. Given this bias level, it is easier for us to process the AC signal using the on-chip ADC in the microcontroller.Figure 4: AC coupling stage for DC bias levelThe AC output from this stage will be passed on to the analog-to-digital converter in the Mega32 microcontroller. The image from the laboratory bench is shown in figure 5. We can see that it is very nice and clean.Figure 5: AC Waveform