Requirements for postgraduate entrance examination of measurement and control specialty

Of course not. 806 Course Name: Fundamentals of Measurement and Control Technology

First, the general requirements of the examination are to master the basic knowledge and theory of measurement and control technology, and to use it reasonably to solve practical problems. Second, the examination content and the proportion of the examination content. The examination content is divided into two modules, A and B. Candidates can choose either module. A module is the theory and technology of precision testing, and B module is the sensing technology and measurement and control circuit.

(a) Unit A: Theory and Technology of Precision Testing

Precision testing theory

(1) The main contents of the test system: the basic concept of the test, the composition of the test system, the mathematical model and frequency characteristics of the test system, and the main performance indicators of the measuring instrument. Basic requirements: the basic concepts of test, measurement and information, value transfer and traceability system; The composition of the test system and the functions of each part; The mathematical model, transfer function and frequency response function of the test system; Frequency characteristics of first-order system and second-order system; Ideal frequency response characteristics and conditions of lossless testing: definition and expression of main performance indexes of measuring instruments.

(2) Signal and its description: description of periodic signal and aperiodic signal, discrete Fourier transform and random signal. Basic requirements: periodic signal and its description; Description of aperiodic signal; Discrete Fourier transform; Definition and classification of stochastic processes; Statistical characteristics of random signals.

(3) The basic concept of error: the definition and expression of error, the concept of precision (accuracy), and the operation of effective numbers and data. Basic requirements: definition and representation of errors, error classification; The concept of precision; The rounding rules and operation rules of numbers can set the number of significant digits as required.

(4) Basic properties and treatment of errors: properties and treatment of random errors, systematic errors and gross errors. Basic requirements: causes and characteristics of random error, systematic error and gross error; Characteristics and treatment methods of normal distribution; Other distributions of random errors; Can correctly calculate the concepts of arithmetic mean, standard deviation of single measurement, standard deviation of arithmetic mean and limit error; Data processing of measurement results of equal precision and unequal precision direct measuring column

(5) The main contents of error synthesis: the calculation of functional systematic error and functional random error, the significance of correlation coefficient, and the synthesis of random error and systematic error. Basic requirements: calculation method of function system error and function random error; Calculation of error synthesis.

(6) The main contents of measurement uncertainty: the concept of measurement uncertainty, the evaluation of measurement uncertainty and the synthesis of measurement uncertainty. Basic requirements: basic terms and sources of measurement uncertainty; Two kinds of evaluation of standard uncertainty, the acquisition method of combined standard uncertainty and extended uncertainty; Uncertainty report.

(7) The main contents of linear parameter least square method: the principle of least square method, normal equation and accuracy estimation. Basic requirements: Normal equation, solution and accuracy estimation of linear parameter least square method for equal precision measurement.

(8) The main content of regression analysis: the basic concepts of regression analysis, unitary linear regression and unitary nonlinear regression. Basic requirements: the solution of linear regression equation, variance analysis and significance test of regression equation. Solution and accuracy analysis of one-dimensional nonlinear regression equation.

2. Precision testing technology

The main contents of (1) length and linear displacement measurement include: standard quantity and standard environment for length measurement, Abbe principle, length and size measurement, form and position error measurement, surface roughness measurement, linear displacement measurement and nanometer measurement technology. Basic requirements: standard quantity and standard environment for length measurement; Abbe principle; Methods and instruments for direct and indirect measurement, absolute measurement and relative measurement of length; The structure of CMM, the type and working principle of probe, and the main contents of coordinate measurement data processing; Measuring principle of laser diffraction filament diameter: the structure and working principle of active measuring instrument, the characteristics of measuring instrument and automatic adjusting instrument in processing; Basic concepts of shape and position error measurement; The concept and evaluation method of straightness error and the commonly used measurement methods and instruments; Common measuring instruments and evaluation parameters for surface roughness; Displacement measurement principle of dual-frequency laser interferometer; Structure and working principle of scanning tunneling microscope and atomic force microscope.

(2) The main contents of angle and angular displacement measurement: natural reference, physical reference, principle of circumferential closure, measurement of angle size and measurement of circumferential indexing error. Basic requirements: angle natural reference, physical reference, circle closure principle; Methods and instruments for direct and indirect angle measurement; Evaluation index of circular indexing error; Absolute and relative measurement methods of circular arc indexing error.

(3) The main contents of speed, rotational speed and acceleration measurement: the basic methods of speed, rotational speed and acceleration measurement. Basic requirements: velocimetry, pitot tube velocimeter, Doppler velocimeter and gyro to measure angular velocity; Electronic digital tachometer, strobe tachometer; Piezoelectric accelerometer, servo accelerometer.

(4) The main contents of force, torque and pressure measurement: the basic methods of force, torque and pressure measurement. Basic requirements: force measuring methods and various force measuring devices; All kinds of weighing sensors and belt scales; Torque measuring method and transmission torque measuring device; Various pressure measuring devices, various vacuum measuring devices.

(5) The main contents of mechanical vibration test: the concept and types of mechanical vibration, various vibration sensors and vibration measurement. Basic requirements: the concept, types and characterization parameters of mechanical vibration; Excitation mode, various vibration exciter; Mechanical model and characteristic analysis of inertial vibration sensor and magnetoelectric vibration speed sensor; Measurement method of natural frequency and damping ratio.

(6) The main content of temperature measurement: the concept of temperature scale and the working principle of various thermometers. Basic requirements: definitions of various temperature scales; Various expansion thermometers and pressure thermometers; The working principle, basic law and various reference terminal processing methods of thermocouple thermometer; Various thermal resistance thermometers and their lead error handling methods: the basic law of thermal radiation and various thermal radiation thermometers.

(7) The main content of flow measurement: the concept of flow and the working principle of various flowmeters. Basic requirements: the definition of flow; Elliptical gear flowmeter; Differential pressure flowmeter for pipeline and weir flowmeter for open channel; Rotor flowmeter and target flowmeter; Various speed measuring flowmeters; Vibrating flowmeter; Thermal mass flowmeter and various derivative mass flowmeters.

(b) module b: sensing technology and measurement and control circuit.

sensing technology

(1) General characteristics of sensors Main contents: Basic concepts of sensors and their static characteristics. Basic requirements: definition and composition of sensors; Main technical indexes of static characteristics of sensors.

(2) The main contents of resistive sensor: working principle, main characteristics, DC bridge, temperature error and compensation, and application of resistive sensor. Basic requirements: resistance strain effect of metal, working principle and characteristics of strain sensor; Piezoresistive effect, working principle and characteristics of piezoresistive sensor; DC bridge, single-arm bridge and differential bridge; Temperature error and its compensation; Application of resistance sensor.

(3) The main content of capacitive sensor: the working principle, main characteristics, basic conversion circuit, optimal design and application of capacitive sensor. Basic requirements: working principle, types and main characteristics of capacitive sensors; The conversion circuit, driving cable technology and equipotential ring technology of capacitive sensor; Application of capacitive sensor.

(4) Main contents of Hall sensor: working principle, main characteristics, error and compensation, and application of Hall sensor. Basic requirements: Hall effect, working principle and main characteristics of Hall sensor; Error sources and compensation measures of Hall sensor circuit model: application of Hall sensor.

(5) The main content of photoelectric sensor: the working principle and characteristics of light source, photoelectric device, optical fiber sensor, laser sensor and grating sensor. Basic requirements: characteristics of typical light sources; Working effect, principle, characteristics and application of photoelectric devices; The structure, working process and application of charge coupled device (CCD); The working principle and application of position sensitive device (PSD): the principle of optical fiber transmission, the principle and characteristics of optical fiber sensors, and the types of optical fiber sensors; Moire fringe and its characteristics, working principle, types and characteristics of grating sensor; Working principle of Michelson interferometer. 2. Measurement and control circuit

(1) Introduction: Types, components and functions of measurement and control circuits; Input and output signals of measurement and control circuit. Basic requirements: the function of measurement and control circuit; Main requirements of measurement and control circuits; Input and output signals of the measuring and control circuit; Types and components of measurement and control circuits.

(2) The main content of signal amplification circuit: operational amplifier; Basic principles and functions of typical measurement and control amplifier circuits; Noise of amplifier. Basic requirements: basic knowledge of operational amplifier, error of operational amplifier and its compensation; Typical measurement and control amplifier circuits include noninverting amplifier circuit, inverting amplifier circuit, basic differential amplifier circuit, high analog ratio amplifier circuit, bridge amplifier circuit, high input impedance amplifier circuit and isolation amplifier circuit. Understand the basic knowledge of amplifier noise.

(3) The main content of signal modulation and demodulation circuit: signal modulation and demodulation; Amplitude modulation and detection; Frequency modulation and frequency discrimination; Phase modulation and phase discrimination; Pulse width modulation and demodulation. Basic requirements: focus on mastering the double-sideband amplitude modulation signal and its expression and waveform, as well as the relationship between carrier signal frequency and modulation signal frequency; Several amplitude modulation methods and envelope detection: the function of precision detection circuit; Characteristics of phase-sensitive detection circuit and its comparison with envelope detection circuit: frequency selection characteristics and phase discrimination characteristics of phase-sensitive detection circuit; Understand the expression and waveform of FM signal; Frequency modulation and frequency discrimination methods; Working principle of frequency meter; Representation and waveform of phase modulation signal; Phase modulation and phase discrimination methods; Expression and waveform of pulse width modulation signal; Pulse width modulation and demodulation methods.