A novel approach for realization of primary vibration calibration standard by homodyne laser interferometer in frequency range of 0.1Hz to 20kHz

Measurement ◽  
2012 ◽  
Vol 45 (8) ◽  
pp. 1941-1950 ◽  
Author(s):  
Naveen Garg ◽  
Omkar Sharma ◽  
Ashok Kumar ◽  
Mark I. Schiefer
Keyword(s):  
Laser Interferometer ◽  
Calibration Standard ◽  
Frequency Range ◽  
Novel Approach

In-orbit performance of the laser interferometer of Taiji-1 experimental satellite

2021 ◽  
pp. 2140004
Author(s):  
He-Shan Liu ◽  
Zi-Ren Luo ◽  
Wei Sha ◽  
Keyword(s):  
Laser Interferometer ◽  
Fused Silica ◽  
Test Mass ◽  
Frequency Range ◽  
Space Antenna ◽  
Satellite Platform ◽  
Laser Interferometer Space Antenna ◽  
Key Technologies ◽  
Carrier Rocket ◽  
Reference Sensor

Taiji-1, which is the first experimental satellite for space gravitational wave detection in China, relies on key technologies which include the laser interferometer, the gravitational reference sensor (GRS), the micro-thruster and the satellite platform. Similarly to the Laser Interferometer Space Antenna (LISA) pathfinder, except for the science interferometer, the optical bench (OB) of Taiji-1 contains reference and test mass (TM) interferometers. Limited by the lower mechanical strength of the carrier rocket and by the orbit environment, the OB of Taiji-1 is made of invar steel and fused silica, and it is aimed to achieve a sensitivity of the order of 100[Formula: see text]pm/[Formula: see text]. The experimental results from in-orbit tests of Taiji-1 demonstrate that the interferometer can reach a sensitivity of 30[Formula: see text]pm/[Formula: see text] in the frequency range of 0.01–10[Formula: see text]Hz, which satisfies the requirements of Taiji-1 mission.

scholarly journals Efficient Numerical Full-Polarized Facet-Based Model for EM Scattering from Rough Sea Surface within a Wide Frequency Range

2019 ◽  
Vol 11 (1) ◽  
pp. 75 ◽  
Author(s):  
Jinxing Li ◽  
Min Zhang ◽  
Ye Zhao ◽  
Wangqiang Jiang
Keyword(s):  
Cross Sections ◽  
High Efficiency ◽  
Wide Frequency Range ◽  
Sea Surface ◽  
Doppler Spectrum ◽  
Frequency Range ◽  
Em Scattering ◽  
Wind Speeds ◽  
Novel Approach ◽  
Rough Sea Surface

A full-polarized facet based scattering model (FPFSM) for investigating the electromagnetic (EM) scattering by two-dimensional electrically large sea surfaces with high efficiency at high microwave bands is proposed. For this method, the scattering field over a large sea facet in a diffuse scattering region is numerically deduced according to the Bragg scattering mechanism. In regard to near specular directions, a novel approach is proposed to calculate the scattered field from a sea surface based on the second order small slope approximation (SSA-II), which saves computer memory considerably and is able to analyze the EM scattering by electrically large sea surfaces. The feasibility of this method in evaluating the radar returns from the sea surface is proved by comparing the normalized radar cross sections (NRCS) and the Doppler spectrum with the SSA-II. Then NRCS results in monostatic and bistatic configurations under different polarization states, scattering angles and wind speeds are analyzed as well as the Doppler spectrum at Ka-band. Numerical results show that the FPFSM is a reliable and efficient method to analyze the full-polarized scattering characteristics from electrically large sea surface within a wide frequency range.

The effective frequency range of an active suspended handle based on the saturation effects of a piezo stack actuator

2016 ◽  
Vol 23 (5) ◽  
pp. 752-769 ◽  
Author(s):  
Ahmad Zhafran Ahmad Mazlan ◽  
Zaidi Mohd Ripin
Keyword(s):  
Excitation Frequency ◽  
Saturation Effect ◽  
Feedback Gain ◽  
Operating Speed ◽  
Frequency Range ◽  
Effective Frequency ◽  
Novel Approach ◽  
Saturation Effects ◽  
Force Displacement ◽  
Proportional Feedback

This paper presents a novel approach to the design of an active suspended handle by identifying the effective frequency range, based on the saturation effects of the piezo stack actuator, in terms of the force-displacement-voltage relationship as a function of the excitation frequency. The effective range allows for proper matching between the operating speed of the machine and the suspended handle. A model of the active suspended handle was developed, which took into account the non-linear saturation effect of the piezo stack actuator. A proportional-integral-derivative controller generated the counter voltage for the piezo stack actuator, using a proportional feedback gain (P) step up method, in order to attenuate the vibration transmitted to the handle. By including the saturation effect, the Pearson’s correlation coefficient ( R2) of the model improved to 0.97, within the frequency range of 50 ∼ 500 Hz. Using this approach, we identified that the effective frequency range of isolation with transmissibility less than unity is between 250 ∼ 450 Hz. The active suspended handle was attached to a die grinder with a nominal operating speed of 25000 rpm and the vibration transmitted from the die grinder to the handle was reduced by 91%.

scholarly journals Employing correlation for wireless components and device characterization in reverberation chambers

2019 ◽  
Vol 8 (1) ◽  
pp. 185-194
Author(s):  
Christoph Cammin ◽  
Dmytro Krush ◽  
Ralf Heynicke ◽  
Gerd Scholl
Keyword(s):  
Correlation Coefficient ◽  
The Novel ◽  
Frequency Range ◽  
Radiation Characteristics ◽  
Reference Equipment ◽  
Mean Values ◽  
Novel Approach ◽  
Complex Correlation ◽  
Measured Sample ◽  
Reverberation Chambers

Abstract. Reverberation chambers are well-proven test environments for radio frequency (RF) measurements. Typically, mean values are taken from the measurements to characterize the equipment under test. In the novel approach presented in this paper, the correlation of measured sample sequences is utilized to detect deviations, in particular of the radiation characteristics, from reference equipment. This approach is exemplified by a measurement setup using several different antennas with the same housing. The complex correlation coefficient and the correlation coefficient with respect to the transferred power of two measured sample sequences are calculated and evaluated for a suitable frequency range to detect differences between the radiation characteristics.

scholarly journals Electromechanical Measurements Of Gd-Doped Ceria Thin Films By Laser Interferometry

2016 ◽  
Vol 1 (1) ◽  
pp. 177 ◽  
Author(s):  
A.D. Ushakov ◽  
N. Yavo ◽  
E. Mishuk ◽  
I. Lubomirsky ◽  
V.Ya. Shur ◽  
...  
Keyword(s):  
Thin Films ◽  
Electromechanical Coupling ◽  
Laser Interferometer ◽  
Laser Interferometry ◽  
Doped Ceria ◽  
Vertical Resolution ◽  
Frequency Range ◽  
Highly Sensitive ◽  
High Vertical Resolution ◽  
Compact Design

Highly sensitive laser interferometer was built to measure electromechanical coupling in Gd-doped ceria Ce<sub>0.9</sub>Gd<sub>0.1</sub>O<sub>2-x</sub> thin films in the frequency range up to 20 kHz. Spurious resonances due to substrate bending were avoided by the special mounting of the film in the center of substrate. Compact design allowed to reach high vertical resolution of about 0.2 pm. Electrostriction coefficient measured in 1 µm thick Ce<sub>0.9</sub>Gd<sub>0.1</sub>O<sub>2-x</sub> film was 4.3×10<sup>-21 </sup>m<sup>2</sup>/V<sup>2</sup> and slightly decreased with frequency till the extensional resonance of the substrate at about 20 kHz occurred. As expected, the displacement varied as a square of applied voltage without any sign of saturation.

The phasemeter of Taiji-1 experimental satellite

2021 ◽  
pp. 2140005
Author(s):  
Zi-Ren Luo ◽  
Tao Yu ◽  
He-Shan Liu ◽  
Keyword(s):  
Laser Interferometer ◽  
Space Missions ◽  
Phase Extraction ◽  
Frequency Range ◽  
Technical Requirements

Taiji-1 is the first demonstrated experimental satellite of Taiji program in China. Phasemeter is one of the key components of the laser interferometer which is responsible for phase extraction of the heterodyne signals. In this paper, we present the architecture and implementation of Taiji-1 phasemeter. The DPLL architecture is used in Taiji-1 which is generally regarded as the best choice for space missions. We test the phasemeter on the ground and the results show that the phasemeter reaches the sensitivity of 600 [Formula: see text]rad/[Formula: see text] in the frequency range of 0.01–1[Formula: see text]Hz. It is further shown that it can reach the accuracy of 30 [Formula: see text]rad/[Formula: see text] in the frequency range of 0.1–1[Formula: see text]Hz, both of which are within the technical requirements of Taiji-1 mission.

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