电大4月考试传感器与测试技术第三次作业

《电大4月考试传感器与测试技术第三次作业》由会员分享，可在线阅读，更多相关《电大4月考试传感器与测试技术第三次作业（10页珍藏版）》请在装配图网上搜索。

1、专业好文档2013年4月考试传感器与测试技术第三次作业一、填空题（本大题共15分，共 5 小题，每小题 3 分）1. 为了使同一型号的传感器有相同的灵敏度，常在传感器线圈两端并联一个 _ ，经标定后固定其阻值。2. _ 是利用MOS二极管电容一电压特性（CV特性）的变化，MOS场效应晶体管（MOSFET）的阈值电压的变化等物理特性做成的半导体气敏元件。3. 表征传感器静特性的指标有 _ 、 _ 、 _ 等4. RC滤波电路中的电阻，不仅消耗希望抑制的信号能量，也消耗希望通过的信号能量。为了克服这一缺点，可采用RC网络和 _ 组成的有源滤波电路，该电路除起滤波作用之外，还可将信号放大，其放大倍数

2、也容易调节。5. _ 除用于家庭磁带录像机之外，还可用于各种机器的结露检测。二、计算题（本大题共30分，共 3 小题，每小题 10 分）1. 磁电式线速度传感器的线圈平均直径D=25mm，气隙磁感应强度B=6000Gs。希望传感器的灵敏度k600（mVcms），求工作线圈的匝数N应为多少？2. 已知信号x（t）试求信号x（0.5t），x（2t）的傅里叶变换。3. 利用电涡流位移传感器和频率计数器测某轴的转速。欲使频率计所读频率的数值等于12转速的数值（如f=50Hz，表示n= 25rmin）。问齿盘的齿数z为多少?若使f的数值等于n，z又为多少?三、简答题（本大题共25分，共 5 小题，每小题

3、 5 分）1. 浅谈测试系统的主要应用？2. 电阻应变式测力传感器的工作原理？3. 简述微传感器的优点。4. 什么是热电偶的分度表？5. 激光检测的特点是什么？主要应用于什么领域的测量？四、综合分析题（本大题共30分，共 3 小题，每小题 10 分）1. 求图1a所示周期矩形信号的三角形式傅里叶级数表达式，并画出幅值谱。2. 求如图1所示周期性方波的复指数形式的幅值谱和相位谱3. 一电涡流测振仪测量某主轴的轴向振动。已知，传感器的灵敏度为15mV/mm，最大线性范围6mm。现将传感器安装在主轴右侧，见图2a。用记录仪记录振动波形，见图b。问： 1、传感器与被检测金属的安装距离l为多少毫米时，可

4、得到较好的测量效果？ 2、轴向振幅的最大值A为多少？ 3、主轴振幅的基频是多少？答案：一、填空题（15分，共 5 题，每小题 3 分）1. 参考答案：可调电阻解题方案：为了使同一型号的传感器有相同的灵敏度，常在传感器线圈两端并联一个可调电阻，经标定后固定其阻值。评分标准：一空一分2. 参考答案：非电阻型气敏元件解题方案：非电阻型气敏元件是利用MOS二极管电容一电压特性（CV特性）的变化，MOS场效应晶体管（MOSFET）的阈值电压的变化等物理特性做成的半导体气敏元件。评分标准：一空一分3. 参考答案：线性度灵敏度重复性解题方案：表征传感器静特性的指标有线性度、灵敏度、重复性等评分标准：一空1分

5、4. 参考答案：集成运算放大器解题方案：RC滤波电路中的电阻，不仅消耗希望抑制的信号能量，也消耗希望通过的信号能量。为了克服这一缺点，可采用RC网络和集成运算放大器组成的有源滤波电路，该电路除起滤波作用之外，还可将信号放大，其放大倍数也容易调节。评分标准：一空一分5. 参考答案：结露传感器解题方案：结露传感器除用于家庭磁带录像机之外，还可用于各种机器的结露检测。评分标准：一空1分二、计算题（30分，共 3 题，每小题 10 分）1. 参考答案：已知D=25mmO.025m，k600（mVcms） 60（Vms），B=6000Gs=0.6T 因为ENBLv，kEv NBL，LD0.025 所以N

6、k（BL）=1274匝解题方案：评分标准：2. 参考答案：解题方案：评分标准：3. 参考答案：解题方案：评分标准：三、简答题（25分，共 5 题，每小题 5 分）1. 参考答案：1产品质量测量，对于各种零部件的测试测量；2设备运行状态监控系统；3故障诊断系统；解题方案：评分标准：2. 参考答案：电阻应变式测力传感器是将力作用在弹性元件上，弹性元件在力作用下产生应变，利用贴在弹性元件上的应变片将应变转换成电阻的变化。然后利用电桥将电阻变化转换成电压（或电流）的变化，再送入测量放大电路测量。最后利用标定的电压（或电流）和力之间的对应关系，可测出力的大小或经换算得到被测力。 解题方案：评分标准：3.

7、 参考答案：1、体积小、重量轻，便携性好，适用面广； 2、微小的敏感元件提高了测量的空间分辨力； 3、固有频率高，工作频率范围大，响应速度快； 4、耗能低； 5、批处理的加工方式使其具有价格优势； 6、特殊的微加工技术使得结构或功能集成更容易实现，可改善性能，并为进一步实现集成传感器或智能传感器奠定了基础。解题方案：此题考察微传感器相对于其他类型传感器的优点。评分标准：4. 参考答案：是热电偶温度传感器在冷端温度为0的条件下，输出热电动势的毫伏值与热端温度之间的对应关系，采用表格表示。不同材料组成的热电极有不同的分度表。常用热电极材料有铜-康铜、镍铬-考铜、镍铬-镍硅。解题方案：评分标准：5.

8、 参考答案：激光检测有精度高、测量范围大、测试时间短、非接触、易数字化、效率高等优点。激光干涉测长技术，目前已广泛地应用于精密长度测量，如磁尺、感应同步器、光栅的检定；精密机床位移检测与校正；集成电路制作中的精密定位等。解题方案：此题考察激光检测的特点和应用范围。评分标准：四、综合分析题（30分，共 3 题，每小题 10 分）1. 参考答案：解题方案：评分标准：2. 参考答案： 解题方案：此题考察周期性信号频谱的计算。评分标准：3. 参考答案：1、取其传感器线性范围的1/2,即取L3mm时，线性度最好，测量范围最大。 2、因为输出ykx，由图b知 y45mV k15mV/mm 所以 x45/1

9、5mm3mm（峰-峰值） 振幅 Ax/2=3/2mm1.5mm 3、由图2b知，主轴振动周期 T20/2ms10ms1010-3s频率 ?1/T1/10-2Hz100Hz解题方案：评分标准：If we dont do that it will go on and go on. We have to stop it; we need the courage to do it.His comments came hours after Fifa vice-president Jeffrey Webb - also in London for the FAs celebrations - said

10、he wanted to meet Ivory Coast international Toure to discuss his complaint.CSKA general director Roman Babaev says the matter has been exaggerated by the Ivorian and the British media.Blatter, 77, said: It has been decided by the Fifa congress that it is a nonsense for racism to be dealt with with f

11、ines. You can always find money from somebody to pay them.It is a nonsense to have matches played without spectators because it is against the spirit of football and against the visiting team. It is all nonsense.We can do something better to fight racism and discrimination.This is one of the villain

12、s we have today in our game. But it is only with harsh sanctions that racism and discrimination can be washed out of football.The (lack of) air up there Watch mCayman Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebration

13、s and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedi

14、ngs against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immediate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russ

15、ian side added: We found no racist insults from fans of CSKA.Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunda.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph,

16、 with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even high

17、er than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will sl

18、owly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be li

19、ke he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will n

20、ot be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,

21、524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there