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The binary inductive voltage dividers (BIVD) have been designed as the 2∶1 ratio reference at frequencies up to 1MHz. In this paper, the BIVDs are described in detail together with the calibration of their ratio errors by a substitution method. The measurement results of the BIVDs have also been given at frequencies from 1 kHz to 1MHz.
Correlation radiometer is the basic unit of interferometer or full polarization radiometer which can obtain the correlation of two receiving channels. The paper presents a novel receiving configuration of correlation radiometer using the digital signal processing to fulfill the IQ demodulation and acquire the band of application requirement exactly. This new receiving configuration can eliminate the...
The ordinary digital camera calibration has been one of the active research fields in computer vision and photogrammetry. This paper proposes a novel calibration method with ease for operation and high accuracy, as well as robustness. This method uses a micro plane grid as the calibration reference object which is photographed for a couple of images in the same direction, applies a high-precision...
We report development of an astro-comb providing >7000 lines spaced by 16 GHz from 500–620 nm. A characterization with an FTS shows it can provide sub-10 cm/s calibration accuracy of astrophysical spectrographs performing exo-Earth searches.
By position estimation of the binocular vision, a robot can accurately obtain the three-dimensional information of an object. The algorithms about camera calibration and stereo match are described in this paper in detail. Not only that, two kinds of camera calibration methods are compared and analyzed in this paper. The method for robot grasping is proved to be effective from experiments. Research...
A digital background calibration technique for capacitors mismatch in multi-bit delta-sigma modulator is proposed in this paper. The approach is correlation-based, in which a single-bit pseudo-random noise (PN) is used to identify the error module, minimizing the analog circuit overhead. This algorithm works by estimating every DAC capacitor in turn with the PN signal injection and compensates for...
We develop an analytical approach to analyze the performance of astro-combs when amplified by a fiber amplifier. Five filtering schemes are compared to optimize side-mode suppression and radial-velocity calibration accuracy of an amplified astro-comb.
We developed a tunable, visible frequency comb near 420nm with 22GHz mode spacing and 20nm spectral width, which is able to calibrate astronomical spectrographs to search Earth-like exoplanets orbiting around stars similar to the Sun.
We propose and analyze an approach to generating broadband astro-combs with 1 cm/s (∼10 kHz) calibration accuracy on astrophysical spectrographs. Implementation of these astro-combs requires a side-mode suppression of 60 dB before nonlinear spectral broadening.
Searches for extrasolar planets using the periodic Doppler shift of stellar spectral lines resulting from the motion of the host star around the barycentre of an extrasolar system have recently achieved a precision of 60 cm/s. To find a 1-Earth-mass planet in an Earth-like orbit, a precision of 5 cm/s is necessary. The sensitivity of astrophysical spectroscopy is presently limited by its wavelength...
High-resolution spectroscopy is a crucial tool for cosmology and the search for extrasolar planets. We present a laser comb with up to 40-GHz line spacing for use as a new spectrographic calibration source.
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