Abstract:The traditional method uses linear frequency modulated signal as the excitation for frequency response measurement and calibration, which can hardly balance the accuracy and efficiency because of its even power spectrum and deficient adjustable parameters. In this paper, we propose a dynamic method for frequency response calibration based on nonlinear frequency sweep. The power spectrum of the nonlinear sweep signal is inhomogeneous, so that the accuracy and efficiency of the calibrating method can be well balanced. The simulation result shows that compared with the traditional method using linear frequency sweep, our method improves the measurement accuracy within specific frequency band using the same sweeping time.

Abstract:Energy-saving on base station rooms is the most important in telecommunication industry, and the decomposition and analysis on the energy-consumption of base station rooms is the primary target. We set up energy-consumption data acquisition system on experimental base station to acquire real-time data. According to the practical traffic and data flow, we further studied the energy-consumption composition alteration rules and working mechanisms on base station rooms.

Abstract:With the modern science and technology high speed developing, the application of high accuracy senor is becoming mature. The MAX1452 is a highly integrated analog-sensor signal processor optimized for digital compensation method of silicon piezoresistive pressure sensor. The MAX1452 is packaged 16-pin SSOP. The MAX1452 provides fully analog signal path, low power consumption and wide-range temperature. The MAX1452 temperature circuit compensation can transforms the signal of silicon piezoresistive pressure sensor into the analog-signal, than the A/D convertor change it into digital-signal. In the whole process, the fully analog signal path introduces no quantization noise in the output signal while enabling digitally controlled trimming with the integrated 16-bit DACS. Offset and span are calibrated using 16-bit DACS, allowing the digital compensation of silicon piezoresistive pressure sensor.

Abstract:In the process of radiation thermometer calibration, according to the verification regulation, the emissivity of radiation thermometers should be set to 1.00, while during the actual calibration process, the correction value of radiation thermometers with different emissivity values is required to give out by customers after the calibration and the emissivity is fixed and not equal to 1.00. In order to realize correction value calculation for wide-range radiation thermometers with arbitrary fixed emissivity in the calibration process, the article uses LabVIEW dichotomy iterative to achieve the integral algorithm of the plank formula and improves the degree of automation in the process of calibration effectively. The article verifies the difference of efficiency between dichotomy and common stepping algorithm, so that the correction value calculation could be efficiently implemented in any band, any emissivity, and any temperature point.

Abstract:In order to adapt to strict requirements of the pharmaceutical industry for quality of medicinal aluminum foil when printed, a print quality detection system for medicinal aluminum foil based on machine vision was developed after analyzing the detection requirements for tiny pinhole defects, words defects on the front side and small foreign body on the back side. A high real-time, high-definition image acquisition environment is built by the linear array CCD camera, bar-shaped LED light source and other necessary hardware. The architecture of the detection system is based on WinSock network communication; the processing results of the multiple industrial computers are transmitted to the central control system through the network communication. The test shows that the detection system can run stably and efficiently in the field and it can improve the automation degree of the print quality detection of medical aluminum foil.

Abstract:A terahertz cross-guide waveguide directional coupler with unsymmetrical crossed slots is proposed in this paper. By adjusting the basic structure of rectangular waveguide and optimizing the parameters of the crossed slots, this waveguide directional coupler realizes a stable coupling flatness, a good directivity and the working bandwidth within the WR4 standard waveguide. The simulation results present good coupling flatness value from -19.9dB~-22.0dB, the isolation value is greater than 32 dB, and the relative working bandwidth is 40%.

Abstract:A method for measuring a specific measurement of spatial dimensions was analyzed using sophisticated platform with digital altimeter, lever dial gauge and standard roll (amount) rods, and a coordinated transposition of double-lever dial gauge approach was adopted to detect spatial dimensions. Comparison of the results of measurement and evaluation of the measurement uncertainty show that this method can solve the low efficiency and accuracy problems of a single micrometer for spatial dimensions detection.

Abstract:In order to solve the problem of modal parameter calibration of modal test system, the modal analysis and modal superposition theory are studied. According to this theory, a closed-loop mode signal control algorithm is proposed. The closed-loop system is composed of 5 exciters. According to this method, the numerical simulation and experiment test are carried out. The results show that the calibration method is feasible and can be separated from the concrete modal structure, and the simulation of different modes can be realized.

Abstract:A double-helical gear is a kind of special gear which can be used on large power transmission devices. It can work perfectly in the overload and high speed transmission system. But the special structure requirements of teeth make the machining process difficult. Especially there is a strict requirement on the symmetry between the teeth and the central shaft, and it is difficult to be tested. Based on the analysis of symmetry for double-helical gears, the main measurement factor was found, and a new test method on CMM was put forward in this article.

Abstract:Through a series of experiments and data, the article discussed the effect of each measurement component on the measurement results of weight magnetic susceptibility when measuring the magnetic properties of weights with the susceptometer method, and analyzed the measurement and determination of geometry correction factor of weights emphatically, and compared the characteristics of different measurement methods to reduce the error of magnetic properties measurement of weights.

Abstract:The calibration of measuring network in medical leakage current testers is researched in compliance with the standard of GB 9706.1-2007. It is necessary to calibrate the input-impedance and transfer-characteristic in the frequency range from DC to 1MHz. It is pointed out that correct frequency response characters are the precondition of leakage current measurement, and the calibration method of network is proposed, whose standard values of input-impedance and transfer-ratio are calculated then. The influence of distributed inductance on the calibration of transfer-characteristic is analyzed, and the high frequency common-mode-rejection ability of voltage meter in network’s respond port is the main error source. Based on the technologies of DDS, I-V conversion and isolation-measurement, a multifunctional leakage current calibrator is developed, which can take automatic sweep in frequency to calibrations of input-impedance and transfer-ratio. The Calibrator meets the requirements of medical leakage current testers well.

Abstract:The reason for uncertainty of displaying indication was analyzed for ultrasonic thickness instruments on basis of calibration samples, couplant, calibration methods, detector of thickness instrument and acoustic velocity.Meanwhile, the relative suggestions were given to assure the accuracy and. reliability of results.

Abstract:An analysis and discussion about the verification method of indentation measuring system on Rockwell hardness testing machine is made in this paper, and it puts forward a method of direct verification and data processing, which can be used as the reference for carrying out the verification work with the indentation measuring system on Rockwell hardness testing machine.

Abstract:As a kind of load standard equipment, EJⅡ-1 deadweight force standard machine has many advantages, and plays an important role in the metrological system about mechanics in our country. But after many years of use, there will be a fault of reduced repeatability. In this paper, through the study of the equipment design, we analyze the cause of this common fault, and put forward an improved scheme to eliminate the fault and recover the performance for this equipment.

Abstract:AMS2750 covers pyrometry requirements for thermal processing equipment used for heat treatment. It covers temperature sensors (commonly thermocouple), instrumentations, thermal processing equipment, system accuracy tests and temperature uniformity surveys. Thermocouple application plays the most important role in pyrometry. This paper analyses the problems familiar and neglected about thermocouples in NADCAP accreditation and in daily use and maintenance.

Abstract:The temperature uniformity is an important index of heat treatment equipment. In practice, it is generally believed that the temperature uniformity is very difficult to conform to the requirements. This article mainly analyzes the influencing factors on the unqualified temperature uniformity and summarizes the improvement methods.

Abstract:TPH type vacuum furnace temperature uniformity test system of temperature compensation system after being used for a long time existence temperature compensation performance degradation, thus unable to achieve accurate compensation, influence on furnace temperature uniformity test results; at the same time, heating equipment to control temperature thermocouple to measure end position of equipment can have important influence. In this paper, the testing methods of the TPH type vacuum furnace are discussed from the above two aspects.