scholarly journals Research on the Dual Modulation of All-Fiber Optic Current Sensor

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 430
Author(s):  
Jianhua Wu ◽  
Xiaofeng Zhang ◽  
Liang Chen
Keyword(s):  
Duty Cycle ◽  
Modulation Frequency ◽  
Measurement Range ◽  
Optical Modulator ◽  
Current Sensor ◽  
Multiplication Factor ◽  
Pulsed Light ◽  
Frequency Multiplication ◽  
Integer Multiple ◽  
Ratio Error

Acousto-optic modulator (AOM) and electro-optical modulator (EOM) are applied to realize the all-fiber current sensor with a pulsed light source. The pulsed light is realized by amplitude modulation with AOM. The reflected interferometer current sensor is constructed by the mirror and phase modulation with EOM to improve the anti-interference ability. A correlation demodulation algorithm is applied for data processing. The influence of the modulation frequency and duty cycle of AOM on the optical system is determined by modeling and experiment. The duty cycle is the main factor affecting the normalized scale factor of the system. The modulation frequency mainly affects the output amplitude of the correlation demodulation and the system signal-to-noise ratio. The frequency multiplication factor links AOM and EOM, primarily affecting the ratio error. When the frequency multiplication factor is equal to the duty cycle of AOM and it is an integer multiple of 0.1, the ratio error of the system is less than 1.8% and the sensitivity and the resolution of AFOCS are 0.01063 mV/mA and 3 mA, respectively. The measurement range of AFOCS is from 11 mA to 196.62 A, which is excellent enough to meet the practical requirements for microcurrent measurement.

scholarly journals Development of a Current Sensor with Broad Current Measurement Range Using High- and Low-Range Parts

2019 ◽  
Author(s):  
JungWon shin ◽  
Shinwon Kang ◽  
SaeWan Kim
Keyword(s):  
Magnetic Force ◽  
Measurement Range ◽  
Current Measurement ◽  
Field Analysis ◽  
Current Sensor ◽  
High Current ◽  
Type Device ◽  
Shaped Part ◽  
Sensor Modeling ◽  
A Current

The measurement range of a conventional current sensor is narrow because it is used with signals relative to the rated values of the measurement range from a voltage-type device. Consequently, multiple current sensors must be used in accordance with the measurement range. To address this problem, this paper proposes a new current sensor with a clamp-shaped part for low current measurement and a simple straight structure for high current measurement. The output signals of the proposed current sensor are amplified with a Hall element using the magnetic force of a rectangular air gap inside the clamp. To verify the characteristics of the proposed current sensor, a current was applied to an external load, and the value determined by the current sensor noted. Then, electromagnetic field analysis was performed through current sensor modeling and the results obtained compared to the actual sensor results. The proposed sensor had a 1% linearity in the output signals and exhibited dynamic characteristics over a wide current range.

The Representation of Amplitude Modulations in the Mammalian Auditory Midbrain

2008 ◽  
Vol 100 (3) ◽  
pp. 1602-1609 ◽  
Author(s):  
Bjarne Krebs ◽  
Nicholas A. Lesica ◽  
Benedikt Grothe
Keyword(s):  
Auditory System ◽  
Duty Cycle ◽  
Modulation Frequency ◽  
Acoustic Signals ◽  
Interpulse Interval ◽  
Neural Responses ◽  
Stimulus Amplitude ◽  
Auditory Midbrain ◽  
Pulse Trains ◽  
The Relationship

Temporal modulations in stimulus amplitude are essential for recognizing and categorizing behaviorally relevant acoustic signals such as speech. Despite this behavioral importance, it remains unclear how amplitude modulations (AMs) are represented in the responses of neurons at higher levels of the auditory system. Studies using stimuli with sinusoidal amplitude modulations (SAMs) have shown that the responses of many neurons are strongly tuned to modulation frequency, leading to the hypothesis that AMs are represented by their periodicity in the auditory midbrain. However, AMs in general are defined not only by their modulation frequency, but also by a number of other parameters (duration, duty cycle, etc.), which covary with modulation frequency in SAM stimuli. Thus the relationship between modulation frequency and neural responses as characterized with SAM stimuli alone is ambiguous. In this study, we characterize the representation of AMs in the gerbil inferior colliculus by analyzing neural responses to a series of pulse trains in which duration and interpulse interval are systematically varied to quantify the importance of duration, interpulse interval, duty cycle, and modulation frequency independently. We find that, although modulation frequency is indeed an important parameter for some neurons, the responses of many neurons are also strongly influenced by other AM parameters, typically duration and duty cycle. These results suggest that AMs are represented in the auditory midbrain not only by their periodicity, but by a complex combination of several important parameters.

Verification and Design of High Precision Eddy Current Sensor for Tip Clearance Measurement

2018 ◽  
Author(s):  
Ziyu Zhao ◽  
Zhenxia Liu ◽  
Yaguo Lyu ◽  
Xinxin Xu
Keyword(s):  
High Precision ◽  
Eddy Current ◽  
High Sensitivity ◽  
Response Speed ◽  
Measurement Range ◽  
Tip Clearance ◽  
Current Sensor ◽  
Eddy Current Sensor ◽  
Planar Coil ◽  
Sensor Coil

A high precision eddy current sensor for tip clearance measurement was proposed to assess the dynamic tip clearance measurement for aero-engine rotator. Based on the Lenz’s law, the eddy current sensor has high sensitivity, quick response speed and strong anti-interference capability, in addition, the simple geometry and easy installation are its main merits. The aim is to study the influence of planar coil structure parameters and excitation signal parameters on the sensor coil measurement, provide the basis for design of practical sensor in turbine tip clearance measurement. The dynamic calibration experiment verified the designed planar sensor coil, the results indicated the sensor resolution was 10μm and the measurement range was not less than 3mm. The dynamic experiment proved the measuring range, resolution, response speed of designed sensor can meet the requirement of turbine blade tip clearance measurement. The work provides experience in eddy current sensor design in different application, not only in turbine. And the future work will focus on the high temperature issues.

Approach to Generate High-frequency Microwave Signal with Frequency Multiplication Factor Tunability by Using Cascaded Mach-Zehnder Modulators

2019 ◽  
Vol 48 (3) ◽  
pp. 307002
Author(s):  
丛雯珊 CONG Wen-shan ◽  
余岚 YU Lan ◽  
沃江海 WO Jiang-hai ◽  
王亚兰 WANG Ya-lan ◽  
王安乐 WANG An-le
Keyword(s):  
High Frequency ◽  
Microwave Signal ◽  
Multiplication Factor ◽  
Frequency Multiplication ◽  
High Frequency Microwave

scholarly journals Developing the Techniques for Solving the Inverse Problem in Photoacoustics

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 24 ◽  
Author(s):  
Mioljub Nesic ◽  
Marica Popovic ◽  
Slobodanka Galovic
Keyword(s):  
Inverse Problem ◽  
Modulation Frequency ◽  
Back Propagation ◽  
Mathematical Physics ◽  
Measurement Range ◽  
High Accuracy ◽  
Parameter Determination ◽  
Minimum Volume ◽  
Self Consistent

In this work, theoretically/mathematically simulated models are derived for the photoacoustic (PA) frequency response of both volume and surface optically-absorbing samples in a minimum volume PA cell. In the derivation process, the thermal memory influence of both the sample and the air of the gas column are accounted for, as well as the influence of the measurement chain. Within the analysis of the TMS model, the influence of optical, thermal, and elastic properties of the sample was investigated. This analysis revealed that some of the processes, characterized by certain sample properties, exert their dominance only in limited modulation frequency ranges, which are shown to be dependent upon the choice of the sample material and its thickness. Based on the described analysis, two methods are developed for TMS model parameter determination, i.e., sample properties which dominantly influence the PA response in the measurement range: a self-consistent procedure for solving the exponential problems of mathematical physics, and a well-trained three-layer perceptron with back propagation, based upon theory of neural networks. The results of the application of both inverse problem solving methods are compared and discussed. The first method is shown to have the advantage in the number of properties which are determined, while the second one is advantageous in gaining high accuracy in the determination of thermal diffusivity, explicitly. Finally, the execution of inverse PA problem is implemented on experimental measurements performed on macromolecule samples, the results are discussed, and the most important conclusions are derived and presented.

Generation of tunable frequency-multiplication factor signal with full range phase shift based on a DPMZM

2020 ◽  
Vol 458 ◽  
pp. 124802
Author(s):  
He Li ◽  
Shanghong Zhao ◽  
Tao Lin ◽  
Kun Zhang ◽  
Wei Jiang ◽  
...  
Keyword(s):  
Phase Shift ◽  
Full Range ◽  
Multiplication Factor ◽  
Frequency Multiplication ◽  
Tunable Frequency
Sign in / Sign up

Export Citation Format

Share Document