High frequency calibration of MEMS microphones using spherical N-waves

2015 ◽  
Author(s):  
S. Ollivier ◽  
C. Desjouy ◽  
P. Y. Yuldashev ◽  
A. Koumela ◽  
E. Salze ◽  
...  
Keyword(s):  
High Frequency ◽  
Mems Microphones ◽  
Frequency Calibration

Consistent high-frequency calibration

2004 ◽  
Vol 28 (11) ◽  
pp. 2277-2295 ◽  
Author(s):  
David Aadland ◽  
Kevin X.D. Huang
Keyword(s):  
High Frequency ◽  
Frequency Calibration

scholarly journals Planck2018 results

2020 ◽  
Vol 641 ◽  
pp. A3 ◽  
Author(s):  
◽  
N. Aghanim ◽  
Y. Akrami ◽  
M. Ashdown ◽  
J. Aumont ◽  
...  
Keyword(s):  
High Frequency ◽  
Major Change ◽  
Systematic Effect ◽  
Microwave Background ◽  
Extensive Analysis ◽  
Systematic Effects ◽  
Single Detector ◽  
End To End ◽  
Frequency Calibration ◽  
Analogue To Digital

This paper presents the High Frequency Instrument (HFI) data processing procedures for thePlanck2018 release. Major improvements in mapmaking have been achieved since the previousPlanck2015 release, many of which were used and described already in an intermediate paper dedicated to thePlanckpolarized data at low multipoles. These improvements enabled the first significant measurement of the reionization optical depth parameter usingPlanck-HFI data. This paper presents an extensive analysis of systematic effects, including the use of end-to-end simulations to facilitate their removal and characterize the residuals. The polarized data, which presented a number of known problems in the 2015Planckrelease, are very significantly improved, especially the leakage from intensity to polarization. Calibration, based on the cosmic microwave background (CMB) dipole, is now extremely accurate and in the frequency range 100–353 GHz reduces intensity-to-polarization leakage caused by calibration mismatch. The Solar dipole direction has been determined in the three lowest HFI frequency channels to within one arc minute, and its amplitude has an absolute uncertainty smaller than 0.35μK, an accuracy of order 10−4. This is a major legacy from thePlanckHFI for future CMB experiments. The removal of bandpass leakage has been improved for the main high-frequency foregrounds by extracting the bandpass-mismatch coefficients for each detector as part of the mapmaking process; these values in turn improve the intensity maps. This is a major change in the philosophy of “frequency maps”, which are now computed from single detector data, all adjusted to the same average bandpass response for the main foregrounds. End-to-end simulations have been shown to reproduce very well the relative gain calibration of detectors, as well as drifts within a frequency induced by the residuals of the main systematic effect (analogue-to-digital convertor non-linearity residuals). Using these simulations, we have been able to measure and correct the small frequency calibration bias induced by this systematic effect at the 10−4level. There is no detectable sign of a residual calibration bias between the first and second acoustic peaks in the CMB channels, at the 10−3level.

scholarly journals High frequency, calibration-free molecular measurements in situ in the living body

2019 ◽  
Vol 10 (47) ◽  
pp. 10843-10848 ◽  
Author(s):  
Hui Li ◽  
Shaoguang Li ◽  
Jun Dai ◽  
Chengcheng Li ◽  
Man Zhu ◽  
...  
Keyword(s):  
High Frequency ◽  
Living Body ◽  
Dual Reporter ◽  
Calibration Free ◽  
Frequency Calibration

Dual-reporter, electrochemical aptamer-based (E-AB) sensors achieve calibration-free measurement of multiple specific molecules in situ in the living body.

scholarly journals Star-Based Calibration of the Installation Between the Camera and Star Sensor of the Luojia 1-01 Satellite

2019 ◽  
Vol 11 (18) ◽  
pp. 2081 ◽  
Author(s):  
Zhichao Guan ◽  
Yonghua Jiang ◽  
Jingyin Wang ◽  
Guo Zhang
Keyword(s):  
High Frequency ◽  
Road Network ◽  
Reference Data ◽  
Calibration Method ◽  
Star Sensor ◽  
Control Points ◽  
Positioning Accuracy ◽  
Ground Control Points ◽  
Position Data ◽  
Frequency Calibration

Ground control points (GCPs) are generally used to calibrate the installation between the camera and star sensor of a satellite in orbit and improve the geometric positioning accuracy of the satellite. However, the use of GCPs for high-frequency calibration is difficult, and it is particularly difficult to acquire accurate GCPs for the image of a nightlight satellite. In this study, we developed a camera-star sensor installation calibration method that eliminates the need for GCPs. In the proposed method, the camera and star sensor lenses are simultaneously pointed at the star, and the camera-star sensor installation is accurately calibrated by processing the star map obtained by the camera and star sensors. Reference data such as road network and Moon position data were used to verify the proposed method and evaluate its positioning accuracy. The results of the application of the method to the positioning of the Luojia 1-01 satellite indicated an accuracy within 800 m, which is comparable with that of the traditional method.

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