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The method of structural-functional organization of multichannel high-speed analog-digital and digital-analog systems on the basis of high-line current-to-current converters is considered. The relevance and practical feasibility of using high-line current-to-current converters to obtain low linearity error and high speed are substantiated.

This paper presents the design and optimization of a novel eddy current speed sensor for rotating rods and cylindrical shafts. The sensor consists of one excitation coil and two pick-up coils. All coils are stationary; we consider air coils, and we also use a magnetic yoke. We utilize a copper coating on an iron rod to increase the sensitivity, and we compare the performance with the performance achieved for an uncoated iron rod. 3D FEM is utilized for analyzing and for optimizing the design of the proposed sensor. The main advantages of the novel sensors are their simplicity, their low cost and their robust configuration. A linearity error of 0.5% has been achieved. The level of accuracy is limited by mechanical factors. A 1D analytical model has also been developed for rapid analysis and optimization of the sensor. An aluminum rod was also used in the measurements for a comparison with the results achieved with the iron rod.

Every year, some of the accidents occur at low speed because of drivers’ blind areas. The probes cannot be assembled on the whole body of vehicle due to cost. In this paper, we present and demonstrate a simple, low-cost obstacle detection system based on capacitive sensors. These sensors are manufactured by conventional printed circuit board. We deduce the sensing principle of the capacitive sensor using mirror image method. A interdigitated sensor with 26 fingers, which dimensions are 30 cm × 10 cm × 0.2 cm, is designed. To read the sensor, we propose a measuring system which includes a wave generator, a C/V converter, a multiplier, some LPFs and amplifiers. It offers a DC-voltage output with low linearity error (0.2%). The experimental results show that human-body and conductor can be easily detected by the sensor compared with wood and wall, and that also verify the validity of the derivation of sensing principle. By testing different persons, the results denote that the measuring system enable detect a child at a distance up to 60 cm that guaranteed the protection system can be valid activated. The last experimental results demonstrate that the more accurate position can be obtain by the linear weighted summation of sensor positions weighted. The proposed detection system also can be used for parking assistance.

A novel transformer-based sensor for a pneumatic cylinder enables measurements of the piston position to be made through a thick conductive cylinder. Unlike existing industrial solutions, which are mainly based on a moving magnet, our sensors do not require modifications to the parts inside the cylinder. Finite element analysis results are compared with measurements at various piston positions and excitation frequencies. Using a suitable model for the magnetic properties of the iron piston bar, we achieved good agreement between the model and reality. When the sensor is operated at 100 Hz, the sensitivity is 200 mV/FS and the raw linearity error is 1.6% of the full 400 mm stroke.

In this brief, a high sensitivity measuring system for capacitive sensor to detect moving target is presented. It mainly consists of a capacitance measuring circuit and a dc-blocking circuit. The capacitance measuring circuit is used to convert a capacitance to a dc voltage and the dc-blocking circuit is employed to extract the voltage variation. The experimental results show that when the measured capacitor is between 1 pF to 7.5 pF, the sensitivity is 3.53 V/pF, the linearity error is 6.13%, the SNR increases from 26.6 dB to 57.7 dB, the resolution is 3.1 fF and the time delay is about $4\,\mu \text{s}$ . Comparing to five other common capacitance measuring circuits, the proposed one offers plain design, high sensitivity, and fast speed. Simulation results show that the proposed dc-blocking circuit has short time delay and unattenuated output. Moreover, as demonstrated by system tests, the proposed measuring system is qualified for capacitive sensor for detection of moving target with different speeds.

In this paper, we report the effect of geometric parameters by calculating the capacitance scale factor of micromachined vibrating wheel on gimbal gyroscope with various shapes and mass conditions. The behavior of capacitance for vibratory torsional gyroscope with various shapes and mass conditions is investigated using MEMS+™. The structure dimensions of the gyroscope are optimized by matching frequencies in driving and sensing modes. The scale factor and linearity error extracted by calculated capacitance have been changed with various shapes condition unless the area of sensing electrodes and the mass of the gyroscope have been fixed. The mass ratio of gimbal and wheel structure is varied to minimize the linearity error.

In this brief, a new low-voltage high-precision bidirectional input current squarer/divider based-full wave rectifier circuit is presented. The designed current squarer is based on a dual translinear loop (DTL) using Floating Gate MOSFET (FGMOS) transistors working in saturation regime. The proposed squarer/divider and rectifier parameters have been evaluated by HSPICE in 180 nm TSMC (level-49) CMOS process. Evaluation outcomes of the designed squarer with VDD=1v shows which the utmost linearity error is 0.28%, the bandwidth is 1.15 GHz, the static and most power dissipation are 20.5 μW and 82 μW, respectively. Also simulation results for rectifier circuit are extracted, which shows that the utmost linearity error is 0.8%, the −3dB bandwidth is 148.4 MHz and the static and most power dissipation are 0.5 μW and 44 μW, respectively. Therewith, to assay the acceptable performance and dependability of the proposed designs Monte Carlo (MC) analysis are accomplished.

The paper presents an operational transconductance amplifier (OTA) with low transconductance (0.62&ndash, 6.28 nS) and low power consumption (28&ndash, 270 nW) for the low-frequency analog front-ends in biomedical sensor interfaces. The proposed OTA implements an innovative, highly linear voltage-to-current converter based on the channel-length-modulation effect, which can be rail-to-rail driven. At 1-V supply and 1-Vpp asymmetrical input driving, the linearity error in the current-voltage characteristics is 1.5%, while the total harmonic distortion (THD) of the output current is 0.8%. For a symmetrical 2-Vpp input drive, the linearity error is 0.3%, whereas THD reaches 0.2%. The linearity is robust for the mismatch and the process-voltage-and-temperature (PVT) variations. The temperature drift of transconductance is 10 pS/&deg, C. The prototype circuit was fabricated in 180-nanometer CMOS technology.

This paper proposes a 16-bit 6-channel high-voltage successive approximation register (SAR) ADC with an optimized 5 + 5 + 6 segmented capacitor array. The lower 10 bits of the capacitor array are all composed of unit capacitors without any calibration unit. Without calibration, the lower 10 bits of the capacitor array can ensure 10-bit conversion accuracy. Every of the upper 6 bits of the capacitor array contains a linearity calibration unit. The linearity error of the upper 6 bits is calibrated by the linearity calibration unit. The 16-bit is manufactured by a $0.6~\mu m$ standard COMS process, and the total chip area of 6-channel ADC including pads is 6.6mm $\times6.6$ mm. As for single channel SAR ADC, the area is 0.9mm $\times2.0$ mm. The measurement results show that the effective conversion accuracy of the SAR ADC reaches 13 bits by using novel differential nonlinearity (DNL) and integral nonlinearity (INL) calibration methods. The power is 80mW, corresponding to a Figure of Merit (FOM) of 48 pJ/conv.-step.

In order to solve the problems in the observation with the SS-Y extensometer, such as background noise and discontinuity of earth tide curve, this paper proposed to improve the stability of the instrument and the smoothness of the earth tide curve by improving the baseline structure of the instrument. In this study, a new φ20*1.2 invar tube was introduced in replacement of the existing φ6 invar rod as the baseline of the instrument and compared with the existing φ6 invar rod on the instrument's linearity, sensitivity and other indexes. Firstly, the SS-Y extensometers using φ6 invar rod and φ20*1.2 invar tube were tested. Test results were then calculated, and accuracy errors of the instruments based on the two baselines were obtained. Finally, their accuracy errors and earth tide curves were compared. Results showed that, compared with the extensometer based on the existing φ6 invar rod, the extensometer based on the new φ20*1.2 invar tube was superior in performance, with linearity error reducing to 0.495% from 0.937%, sensitivity increasing to 68.65 mV/μm from 65.46 mV/μm, and earth tide curve growing more stable and continuous. Keywords: Invar tube, Extensometer, Ground deformation, Background noise, Earth tide

In the previous chapter, we explored the use of linear rule based ensemble methods for the number of faults prediction. In that work, we used four different ensemble methods, each of them combines the outputs of base learners in a linear form. Results of experimental analysis showed that a stable and accurate fault prediction performance could be achieved using linear rule based ensemble methods. However, these ensemble methods capture only the weighted contributions of base learners and combine them in linear way, which may sometimes suffers from the linearity error problem of fitting in a straight line (Fox in Regression diagnostics: an introduction. Sage, 1991 [1]).

A cross-capacitance liquid level sensor is based on the principle of cross capacitance. This study designed a new single-tube cross-capacitance fuel-level sensor. The fuel-level measurement model is established for a single-tube cross-capacitive sensor, and the relationship between the measured liquid level and sensor output capacitance is derived. The characteristics of the sensor were tested experimentally. The experimental results demonstrate that the linearity error of the liquid-level sensor of the single-tube calculation for the spacecraft is &plusmn, 0.48%, the repeatability error is &plusmn, 0.47%, and the hysteresis error is &plusmn, 0.68%. The cross-capacitive fuel-level sensor developed in this study can be used in the fuel tank of spacecrafts owing to its low weight and high precision.

This paper presents an approach to seeker-azimuth determination using the gyro rotor and optoelectronic sensors. In the proposed method, the gyro rotor is designed with a set of black and white right spherical triangle patterns on its surface. Two pairs of optoelectronic sensors are located symmetrically around the gyro rotor. When there is an azimuth, the stripe width covering the black and white patterns changes. The optoelectronic sensors then capture the reflected optical signals from the different black and white pattern stripes on the gyro rotor and produce the duty ratio signal. The functional relationship between the measured duty ratio and the azimuth information is numerically derived, and, based on this relationship, the azimuth is determined from the measured duty ratio. Experimental results show that the proposed approach produces a large azimuth range and high measurement accuracy with the linearity error of less than 0.005.

The low temperature coefficient and high linearity of the input-output characteristics are both required for high-performance microelectromechanical systems (MEMS) capacitive accelerometers. In this work, a structural designing of a bulk MEMS capacitive accelerometer is developed for both low temperature coefficient and high linearity. Firstly, the contrary effect of the wide-narrow gaps ratio (WNGR) on the temperature coefficient of the scale factor (TCSF) and linearity error is discussed. Secondly, the ability of an improved structure that can avoid the contrary effect is illustrated. The improved structure is proposed in our previous work for reducing the temperature coefficient of bias (TCB) and TCSF. Within the improved structure, both the TCSF and linearity error decrease with increasing WNGR. Then, the precise designing of the improved structure is developed for achieving lower TCB, TCSF, and linearity error. Finally, the precise structural designing is experimentally verified.

as everyone knows, conditioning F2N2(Feed Forward Neural Network) in many ways, but ways, but has so far failed to completely solve the "convergence not quickly" and "convergence is not robust"of these two problems, thus affecting the application of F2N2. Aiming at this problem, pro this paper puts forward a new method of processing and application of F2N2, the method of flexible BPNN (Back Propagation Neural Network) algorithm and hierarchical optimization algo-rithm as a whole, each layeris independent rights attached to the conditioning process, carefully con-structed F2N2objective function is non linear series based on the description, not only can the optimization of each layer of the weight problem is simplified to a linear problem, but also can effec-tively controlthe linearity error. This paper provides several examples of application of F2N2automa-tic detection, the results of application show that, this method is superior to other methods.

In this brief, a new low-voltage CMOS circuit to produce current-mode exponential characteristics is proposed. MOSFET transistors in weak-inversion region and translinear principle for the temperature cancellation were used. The functionality of the proposed design confirmed with 0.35 μm CMOS process technology using ±0.75 V supply voltage. Results demonstrate the theoretical analysis and verify the efficiency of the proposed structure compared with previously reported designs. Around 96 linear-in-dB output current range is achieved with ±0.5 dB linearity error over normalized input range from -5.75 to 5.75. The maximum deviation in the output current is ±1.27 and ±3.35 dB due to 100 °C temperature variations and ±10% supply voltage fluctuation, respectively.

Clamp-on ultrasonic flowmeters geometry includes four different materials in the ultrasound propagation path: wedge, coupling material, pipe and liquid. In this case, oblique incidence ultrasonic beam generated by the emitter transducer is split into several paths caused by multiple reflections in pipe wall or because of propagation mode conversion at interfaces. These multiple paths are recombined at the reception transducer aperture, producing a single signal whose amplitude and phase depend on which proportion each path contributes. The objective of this paper is to quantify this phenomenon and analyses the implications it has on the accuracy of Clamp-on ultrasonic flowmeters as a function of the fluid that flows inside the pipe. According to simulations, based on 2D ray tracing model and experimental measurements, the variations in the recombination signal at the reception transducer produces a linearity error that in case of the installation under test, Z-mode transducers configuration on PVC pipe, could reach a value of 3.2%.

This paper presents a methodology of calibration to reduce the linearity error of gain in Time amplifier (TA). We divide the input range to several segments and calculate the average of maximum and minimum TA gain in each segment. We also have the checking points to check the width of input interval and decide which segment and corresponding TA gain is for the measured interval. The checking point is the maximum interval in each segment. The input range for each segment is 50 ps, that is, 0–50 ps is the first segment, 50–100 ps is the second segment, and so on. For the TA which the measured range is 700 ps, we divide the range to 14 segments and there is its corresponding TA gain in each segment. The gain error will be reduced from 0.82% to 0.33% and the distortion caused by gain error will be reduced from 5.74 ps to 0.51 ps.

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This article analyses and explains the implications that dispersive materials have over the linearity in flow measurement when a Clamp-on ultrasonic flowmeter is used. This is of capital importance because dispersive materials are commonly used in the manufacture of transducer wedges and pipes. The evaluation of this phenomenon has been tested by experimental measurement. The used setup consisted of a water flow calibration facility where a commercial Clamp-on ultrasonic flowmeter was installed on it and its flow measurement was compared with a reference flowmeter. Two experiments have been conducted. A first experiment was performed to evaluate only the effect produced by the fact that the transducer wedge is made of dispersive material. For this reason, an ultrasonic flowmeter was installed on a pipe made of non-dispersive material, in this case, an INOX pipe. Linearity error introduced by the wedge was below 1%. This error complies with the accuracy specification of the ultrasonic flowmeter given by the manufacturer (±1.5%). Finally, a second experiment consisted of installing the ultrasonic flowmeter on a dispersive pipe (PVC pipe) in order to measure the worst condition (both materials, wedge and pipe, were dispersive). Under this condition, the linearity error was increased until it reaches a value of 6.4%. Moreover, in case of a dispersive material pipe, the bigger the pipe thickness is, the bigger non-linearity error is reached.

This article explains how a multi-frequency ultrasonic beam path is split due to passing through dispersive materials and the implications that it has in flow measurement using a Clamp-on ultrasonic flowmeter. The importance of knowing this phenomenon is because dispersive materials are commonly used in the manufacture of transducer wedges and plastic pipes. Splitting of the ultrasonic beam path occurs when the incident angle is not normal to the surface of the pipe and a coupling wedge is necessary. The diffraction angle is produced at the boundaries among materials with different propagation velocities (according to Snell’s law), and furthermore, in dispersive materials, the propagation speed depends on frequency. Therefore, when the excitation signal contains several frequential components, each frequency travels with a different velocity. Under this circumstance, different diffraction angles are produced for each frequency at the boundaries between materials. As a result of splitting the path, the ultrasonic beam widens and the reception transducer aperture becomes too small to receive all the frequential components contained in the ultrasonic beam. Thus, when the ultrasonic beam is carried by the liquid flowing inside the pipe, the reception transducer receives different frequential contributions, producing change in its spectral composition. As a consequence of the mixing of these frequencies, the reception signal is modulated in phase and amplitude. Moreover, modulation will change as a function of frequential composition that is combined at the reception transducer. This is the origin of the linearity error in Clamp-on ultrasonic flowmeters.

This paper explains and demonstrates how an atomic force microscope (AFM) is working and how can be improved the measurements realized with this system. At the begining of the paper is a complex presentation of AFM and its improvement with capacitive sensors. Starting from the obtained information, we studied the influence of quality and linearity error of sensors to characterize surfaces using atomic force microscopy. We used the device that had sensors with a linearity error of 0.1%. For another set of measurements we used sensors with linearity error of 0.01%. Experiments realized on CoCrMo and Ti6Al4V materials surfaces demonstrated that the accuracy of sensors, respectively, the linearity error, from the measurement system has an important influence.

The bending sheet metal inevitably exist bending errors including angle error, linearity error and length error of sideline for reasons that the structure of press brake, the manufacturing precision of press brake and mould and the inhomogeneous characteristics of processed sheet metal. The processing errors of sheet metal can affect the assemblage, increasing subsequent repair to the mold and forming calibration, extending the product development cycle, restricting the further promotion and application of bending forming, especially on the forming high strength and high spring-back sheet metal. The PBH110-3100 CNC press brake in Jiangsu Yawei Co.Ltd. is studied to increase the bending precision of press brake in this study. The bending errors in press break are analyzed in depth according to the elastic mechanics theory, and the rule that the manufacturing precision of press brake affect the press precision is educed. The analysis results have real significance on improving the press precision and reliability of press brakes.

A new kind of straightness error measurement system based on laser interference is developed. High stability He-Ne laser beam which is collimated and broadened is cast on wedge-shaped glass plate, on which back and front the light reflects and interfere. The angle of the guide and target would be changed when the motion of the target is along the guide, if there is linearity error existing in the guide. So interference stripes would be moved by the changed angle of the guide and target. In this way the straightness error of the guide is transferred to the displacement of the interference stripes. Then interference stripes are tested by photoelectricity sensor and deviation of the laser beam is acquired. The comparison tests and repeated tests show that the straightness error is 623.103μm when the tested long guide is 50 meters long.

This paper presents a new current-mode squaring circuit. The design is based on MOSFETs translinear principle in strong inversion. A new compensation technique to minimize the second order effects caused by carrier mobility reduction in short channel MOSFETs is proposed. Tanner T-spice simulation tool is used to confirm the functionality of the proposed design in 0.18 µm CMOS process technology. Simulation results indicate that the maximum linearity error is 1.2 %; power consumption is 326 µW and bandwidth of 340 MHz.

A long rail straightness measurement method is given for the portable laser alignment measurement system which is based on laser shearing interference fringes. Through theoretical derivation, mathematical model is set up between the laser phase differential linearity error and shearing interferometry. Large numbers of experiments have verified correctness of long rail straightness measurement method, analyzed the cause of error and provided ways for error reduction.

Indirect time of flight cameras are increasingly being used in a variety of applications to provide real-time full field of view range measurements. Current generation cameras suffer from systematic linearity errors due to the influence of harmonics in the system and motion errors due to the requirement of taking multiple measurements. This paper demonstrates that replacing the standard phase detection algorithm with the windowed discrete Fourier transform can improve the root mean square (RMS) axial motion error with distance from 0.044±0.002 m to 0.009±0.004 m and the range from 0.112±0.007 m to 0.03±0.01 m for an object with a velocity of 2 m/s using a measurement time of 125 ms. This algorithm also improves the linearity of the camera by removing systematic errors due to harmonics, decreasing the RMS linearity error from 0.018±0.002 m to 0.003±0.001 m. This paper establishes the robustness of the windowed discrete Fourier transform, demonstrating that it effectively eliminates axial motion error over a variety of velocities and modulation frequencies. The potential for tailoring phase detection algorithms to specific applications is also demonstrated.

This paper presents an ultra low power differential voltage-to-frequency converter (dVFC) suitable to be used as a part of a multisensory interface in portable applications. The proposed dVFC has been designed in 1.2-V 0.18-μm CMOS technology, and it works properly over the whole differential input range (0.6 ± 0.6 V) providing an output frequency range of 0.0---0.9 MHz. The system has been tested for temperature variations from Â?40 to +120 °C and supply voltage variations of up to 30 %, being the maximum linearity error in the worse case of 0.017 %. Simulations against common mode voltage variations show a deviation in the output frequency of 0.4 %. This dVFC has power consumption below 60 μW, and it includes an enable terminal that sets the system in a sleep mode (180 nW) while no conversion is request. The dVFC occupies an active area of 250 μm A— 150 μm.

For the dispersion problem of the widespread sensors in the R & D process of measuring instruments, this paper proposes a practical method for the automatic calibration of linearity error. Meanwhile, it takes the pressure sensor as an example to describe different calibration methods such as using the hardware, the combination of software and hardware, using the software.

The operating performance of micro-gyroscope may be easily influenced by various factors, which changes the dynamic response accordingly. Generally, the influences can’t be quantified because of the complexity, and the accurate sensitivity and linearity measuring of micro-gyroscope meets enormous difficulties. In order to accomplish corresponding measuring and analysis accurately and efficiently, input excitation waves are designed based on mathematical analysis of the measuring principles and vibration response, and each measuring of sensitivity and linearity can be analyzed in a single test. In this way, the influences from manual operation and variation of measuring environment are well eliminated, and some key parameters of the dynamic response are obtained, such as sensitive voltage, response function, linearity error, etc. In addition, problems about imbalance in double drive vibration, design of the minimum excitation voltage and evaluation of the measuring error are also described. Therefore, some important references are provided for subsequent design, experiment and engineering application.

Crack and strain detecting is an important part of Structure Health Monitoring for aircrafts in fatigue environment. A signal conditioning circuit of a new strain-crack detecting system is developed in this paper. This circuit can deal with both intelligent coating sensor and strain gage, which have a great different original resistance between the two kinds of sensors. Comparing to the Wheatstone Bridge, when the strain is being detected, the new circuit gets rid of the influences of the lead-wires and decreases the wires’ number. The principle and the constitution of the circuit are introduced. And the circuit’s performances are demonstrated by a series of experiments. The linearity error is small and the stability is good.

In this study bimanual grip-force coordination was quantified using a novel "Gripper" system that records grip forces produced while holding a lower and upper unit, in combination with the lift force necessary to separate these units. Children with unilateral cerebral palsy (CP) (aged 5-14 years, n=12) were compared to age matched typically developing (TD) children (n=23). Compared to TD, the CP-group is much slower and takes 50% more time to generate grip and lift forces with more fixating force before lifting the upper unit. In addition the coordination between forces in both hands is reduced. The CP-group increases the lift force in the upper hand 2.5 times more than the holding force when pulling the two units apart, while this is only 1.5 times in TD. Moreover, the correlation between forces generated in both hands in the CP-group is lower. The lack of fine tuning of the forces, measured by the linearity error is increased, especially when the magnet load keeping the unit together is low. The results indicate an impaired pull-hold synergy between upper and lower hand and the lift force. Bimanual tasks evaluating bimanual grip and lift forces in children with CP and can give us new insights in the underlying force control mechanisms of the spastic hand.

An analog multiplier driven by a single supply voltage is proposed. Some improvements are introduced so as to get a higher performance. The proposed analog multiplier can work precisely in four quadrants with a very small THD. An added OTA keeps the linearity error of the circuit smaller than 1%. The presented multiplier is designed on the 0.6 μm BCD process and the simulation results by HSPICE shows a perfect performance. It can be used in any system that requires a high performance analog multiplier.

The use of water for wudhu activities in general uses a manually tapped faucet so that water from the tank will come out. But performing wudhu in this way can result in waste of water in the reservoir. If the faucet continues to burn during the ablution process, there will be a time when water is not needed, that is when the process of washing the body part intended in ablution, so that at that time the water will be wasted. Another problem is if the supply of water sources is limited or in difficult terrain. Therefore it is necessary to make a tool that can improve the effectiveness of using ablution water using infrared sensor application that will activate the valve and open the tap water automatically only if there is a hand or body part detected by the sensor. The speed of the water being pumped will be further slowed by using the PWM (Pulse Width Modulation) method according to the water level of the tank that is detected by the ultrasonic sensor. The results of the study have been done sensitivity of ultrasonic sensors to the PWM control linearity error of 2.02%. And Data Test results of faucet ablation water wudhu adjustable infrared sensor can detect the object distance as far as 5-30 cm. If the input object is more than 30 cm, then the water does not come out.

A bridge resistance deviation-to-period (BRD-to-P) converter is presented for interfacing resistive sensor bridges. It consists of a linear operational transconductance amplifier (OTA) and a current-controlled oscillator (CCO) formed by a current-tunable Schmitt trigger and an integrator. The free running period of the converter is 1.824ms when the bridge offset resistance is 1kΩ. The conversion sensitivity of the converter amounts to 3.814ms/Ω over the resistance deviation range of 0-1.2Ω. The linearity error of the conversion characteristic is less than ±0.004%.

Linearity is a very important parameter for seamless steel pipes. A real-time and on-line visual measurement system for seamless steel pipe linearity is presented. The system consists of several structured-light visual sensors. Each sensor can achieve the coordinate of the center of partial steel pipe in its local coordinate system. Through global calibration, all coordinates measured can be transformed into an integrated coordinate system. The linearity error of steel pipe can be assessed. This method can fulfill 100% on-line and real-time linearity measurement. A pair structure-light sensor is designed to improve accuracy and a suspension-wires method for sensor calibration and global calibration is used. Through experiments, it shows that the method not only meets the need of precise calibration but also significantly improves the efficiency and feasibility.

Rotary variable differential transformer (RVDT) sensors are used for industrial applications and are appreciated for their frictionless operation, reliability, linearity and sensitivity. The sensor shown here derives from a classic RVDT and is based on a differential rotating transformer. The functioning principle is explained and experimental measurements are shown. The originality of the studied sensor lies in the transverse flux design which gives a linearity error less than 0.1% of the stroke. However, this transverse flux circulation has uncommon features for an electrotechnical system due to flux paths which are not enclosed in radial planes. Finite element and experimental analysis are used for the magnetic study. This study aims to enhance sensor performances and manufacturing easiness.

This paper presents the linearity characterization of an analog-to-digital converter (ADC). The input signal is noise, which allows low analog area overhead for built-in self-test (BIST). The linearity error estimation is proposed based on the spectral analysis of only the output of the converter. This paper presents the underlying theory and practical results supporting the effectiveness of the proposed method.

A confocal laser displacement sensor using a micro-machined varifocal mirror is reported. The focal length modulation is a key function of the confocal sensor. The mechanism of the focal length modulation determines the measurement speed and range. Here, we propose application of the micro-machined varifocal mirror for the modulation. The varifocal mirror can realize faster modulation, small size, and low energy consumption for the confocal displacement sensor. The electrostatically actuated varifocal mirror made by single crystalline silicon is used. The working distance of the sensor is designed to be 31 mm. The actuating range at 7 kHz is 310 μm. The linearity error in the actuating range is from -1.1% to 1.2%.

An optimum boundary design method used in pre-amplifiers stage of interpolation and averaging flash ADC is demonstrated in this work. Without costing a large number of dummy amplifiers and consuming over-range voltage headroom, the proposed technique improves linearity error at the boundary of pre-amplifier offset averaging network. A prototype 8bit flash ADC achieves an 1GSPS sampling speed with a 430mA current consumption in 1.8V supply, the experimental result shows that this optimum method is suitable for high speed flash ADC with interpolation and averaging network.

In the paper design and analysis of an off-axis absolute rotary position sensor setup is described that is intended to use in realizing accurate and reliable absolute angle measurement to be applied in precise control of electric (e.g. vehicle) drives. A solution of using magnetic position sensing elements in combination with two differently magnetized ferromagnetic rings is presented. By assuming a specific setup the algorithm of determining absolute position is given, as well by analyzing the measurement errors, a compensation scheme is elaborated. By using this scheme the linearity error of the sensor setup can significantly be reduced without applying any expensive equipment.

A single width NIM module that includes eight channels TAC (time-to-amplitude converter) and QAC (charge-to-amplitude converter) is introduced in the paper, which is designed for the large neutron wall detector to measure charge (energy) and time interval simultaneously [1]. The module mainly adopts a high precision gated integral circuit to realize TAC and QAC. The input range of TAC is from 30 ns to 1 us, and the input range of QAC is from 40 pC to 600 pC. The linearity error of TAC is lower than 1.28 %, and the time resolution of TAC is less than 0.871 %. The linearity error of QAC is lower than 0.81 %, and the resolution of QAC is better than 0.936 %.

This paper presents a new ultra-low-voltage current-mode four-quadrant analog multiplier. A floating-gate technique is used to provide operating at a supply voltage of 0.75 V for the proposed circuit. PSPICE simulators using 0.18 µm TSMC CMOS process are used to show the workability of the multiplier. Simulation results show that the circuit has a linearity error of 1.5 % for the input current 8 µA, total harmonic distortion of 0.96 % for the input current 8 µA peak and quiescent power consumption of 19.9 µW.

This paper presents a new current-mode squaring circuit. The design is based on MOSFETs translinear principle in strong inversion. A new compensation techniques to minimize the second order effects caused by carrier mobility reduction in short channel MOSFETs is proposed. Tanner T-spice simulation tool is used to confirm the functionality of the proposed design in 0.18μm CMOS process technology. Simulation results indicate that the maximum linearity error is 1.16 % and the power consumption is 331μW.

A novel differential-type magnetic sensor based on the giant magnetoimpedance (GMI) effect, integrating the impedance magnitude and phase characteristics of the amorphous wire due to varying the extern magnetic field, is presented in this paper. The sensor consists of a conditioning circuit based on orthogonal vector lock-in amplifier and differential-type amplifier, and a differential-type sensing head with double sensing elements. Besides, the characteristics of our amorphous wires and the construction of the sensing head are also described in this paper. Especially, a masterly and simple design for integrating the in-phase and quadrature output of orthogonal vector lock-in amplifier utilized in the conditioning circuit is described and analyzed in detail. Multiple measurements show that the sensitivity of the GMI magnetic sensor can achieve about 748 mV/Oe with the full measurement range of ±2.0 Oe, while the linearity error is about 0.92%FS.

A model of the linear R-2R ladder digital-to-analog converter (DAC) is developed in terms of the ratios of the effective resistances at the nodes of the ladder. This formulation demonstrates clearly why an infinite number of different sets of resistors can produce the same linearity error and shows how this error can be reduced by trimming. The relationship between the weights of the bits and the resistor ratios suggests appropriate trimming, design, and test strategies.

A design of the resistive mirror-based voltage-controlled resistor (VCR) in bipolar technology is presented. The resistive mirror has been designed using the current-mode signal processing. The modification of the translinear reduction of the "log-antilog" analog multiplier/divider working with currents has been used. Simulation results show the linearity error less than 0.4% in a wide operating range.

A novel voltage-tunable, low-voltage linear CMOS transconductor design is described. The design is based on the improvement of the cross-coupled pairs. SPICE simulation results show that using BSIM models, MOSIS 2-μm n-well process parameters and a power supply of ±2.5 V, the linearity error is less than 0.4% over a differential input voltage range of ±1.2 V. The THD for a differential input voltage of 1\,\hbox {\it V}_{\it {pp}} at 1 kHz is 1.3%.