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Journal articles on the topic 'Low Frequency Instrument'

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Author: Grafiati

Published: 14 March 2023

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1

Vujicic, V. V., S. S. Milovancev, M. D. Pesaljevic, D. V. Pejic, and I. Z. Zupunski. "Low-frequency stochastic true RMS instrument." IEEE Transactions on Instrumentation and Measurement 48, no. 2 (April 1999): 467–70. http://dx.doi.org/10.1109/19.769630.

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2

Lawrence, C. R. "The low frequency instrument on Planck." New Astronomy Reviews 47, no. 11-12 (December 2003): 1025–32. http://dx.doi.org/10.1016/j.newar.2003.09.009.

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3

Vujicic, V. "Generalized low-frequency stochastic true RMS instrument." IEEE Transactions on Instrumentation and Measurement 50, no. 5 (2001): 1089–92. http://dx.doi.org/10.1109/19.963164.

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4

Sandri, M., F. Villa, M. Bersanelli, C. Burigana, R. C. Butler, O. D'Arcangelo, L. Figini, et al. "Planckpre-launch status: Low Frequency Instrument optics." Astronomy and Astrophysics 520 (September 2010): A7. http://dx.doi.org/10.1051/0004-6361/200912891.

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5

Aghanim, N., C. Armitage-Caplan, M. Arnaud, M. Ashdown, F. Atrio-Barandela, J. Aumont, C. Baccigalupi, et al. "Planck2013 results. II. Low Frequency Instrument data processing." Astronomy & Astrophysics 571 (October 29, 2014): A2. http://dx.doi.org/10.1051/0004-6361/201321550.

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6

Hamza, Veton, Bojan Stopar, Tomaž Ambrožič, Goran Turk, and Oskar Sterle. "Testing Multi-Frequency Low-Cost GNSS Receivers for Geodetic Monitoring Purposes." Sensors 20, no. 16 (August 5, 2020): 4375. http://dx.doi.org/10.3390/s20164375.

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Global Navigation Satellite System (GNSS) technology is widely used for geodetic monitoring purposes. However, in cases where a higher risk of receiver damage is expected, geodetic GNSS receivers may be considered too expensive to be used. As an alternative, low-cost GNSS receivers that are cheap, light, and prove to be of adequate quality over short baselines, are considered. The main goal of this research is to evaluate the positional precision of a multi-frequency low-cost instrument, namely, ZED-F9P with u-blox ANN-MB-00 antenna, and to investigate its potential for displacement detection. We determined the positional precision within static survey, and the displacement detection within dynamic survey. In both cases, two baselines were set, with the same rover point equipped with a low-cost GNSS instrument. The base point of the first baseline was observed with a geodetic GNSS instrument, whereas the second baseline was observed with a low-cost GNSS instrument. The results from static survey for both baselines showed comparable results for horizontal components; the precision was on a level of 2 mm or better. For the height component, the results show a better performance of low-cost instruments. This may be a consequence of unknown antenna calibration parameters for low-cost GNSS antenna, while statistically significant coordinates of rover points were obtained from both baselines. The difference was again more significant in the height component. For the displacement detection, a device was used that imposes controlled movements with sub-millimeter accuracy. Results, obtained on a basis of 30-min sessions, show that low-cost GNSS instruments can detect displacements from 10 mm upwards with a high level of reliability. On the other hand, low-cost instruments performed slightly worse as far as accuracy is concerned.

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7

Wilson, Gavin, Jacob Conrad, John Anderson, Andrei Swidinsky, and Jeffrey Shragge. "Developing a low-cost frequency-domain electromagnetic induction instrument." Geoscientific Instrumentation, Methods and Data Systems 11, no. 2 (August 5, 2022): 279–91. http://dx.doi.org/10.5194/gi-11-279-2022.

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Abstract. Recent advancements and the widespread availability of low-cost microcontrollers and electronic components have created new opportunities for developing and using low-cost, open-source instrumentation for near-surface geophysical investigations. Geophysical methods that do not require ground contact, such as frequency-domain electromagnetics, allow one or two users to quickly acquire significant amounts of ground resistivity data in a cost-effective manner. The Colorado School of Mines electromagnetic system (CSM-EM) is a proof-of-concept instrument capable of sensing conductive objects in near-surface environments, and is similar in concept to commercial-grade equipment while costing under USD 400 to build. We tested the functionality of the CSM-EM system in a controlled laboratory setting during the design phase and validated it over a conductive target in an outdoor environment. The transmitter antenna can generate a current of over 2.5 A, and emit signals that are detectable by a receiver antenna at offsets of up to 25 m. The system requires minor refitting to change the functioning frequency, and has been operationally validated at 0.4 and 1.6 kHz. The receiver signal can be measured by off-the-shelf digital multimeters. Future directions will focus on improving the electronic and mechanical stability of the CSM-EM with the goal of using acquired data to make quantitative measurements of subsurface resistivity.

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8

Zacchei, A., D. Maino, C. Baccigalupi, M. Bersanelli, A. Bonaldi, L. Bonavera, C. Burigana, et al. "Planckearly results. V. The Low Frequency Instrument data processing." Astronomy & Astrophysics 536 (December 2011): A5. http://dx.doi.org/10.1051/0004-6361/201116484.

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9

Pjevalica, V., and V. Vujicic. "Further Generalization of the Low-Frequency True-RMS Instrument." IEEE Transactions on Instrumentation and Measurement 59, no. 3 (March 2010): 736–44. http://dx.doi.org/10.1109/tim.2009.2030874.

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10

Aghanim, N., C. Armitage-Caplan, M. Arnaud, M. Ashdown, F. Atrio-Barandela, J. Aumont, C. Baccigalupi, et al. "Planck2013 results. IV. Low Frequency Instrument beams and window functions." Astronomy & Astrophysics 571 (October 29, 2014): A4. http://dx.doi.org/10.1051/0004-6361/201321544.

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11

Rudakov, T. N., A. V. Belyakov, and V. T. Mikhaltsevich. "A low-frequency instrument for remote nuclear quadrupole resonance experiments." Measurement Science and Technology 8, no. 4 (April 1, 1997): 444–48. http://dx.doi.org/10.1088/0957-0233/8/4/013.

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12

Dolgikh, Grigoriy Ivanovich, Stanislav Grigor’evich Dolgikh, Sergey Nikolaevich Kovalyov, Vladimir Aleksandrovich Chupin, Vyacheslav Aleksandrovich Shvets, and Sergey Vladimirovich Yakovenko. "Super-low-frequency laser instrument for measuring hydrosphere pressure variations." Journal of Marine Science and Technology 14, no. 4 (July 23, 2009): 436–42. http://dx.doi.org/10.1007/s00773-009-0062-5.

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13

Stadler, Adam, and Andrzej Dziedzic. "Virtual instruments in low-frequency noise spectroscopy experiments." Facta universitatis - series: Electronics and Energetics 28, no. 1 (2015): 17–28. http://dx.doi.org/10.2298/fuee1501017s.

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Low-frequency noise spectroscopy (LFNS) is an experimental technique to study noise spectra, typically below 10 kHz, as a function of temperature. Results of LFNS may be presented as the ?so-called? noise maps, giving a detailed insight into fluctuating phenomena in electronic devices and materials. The authors show the usefulness of virtual instrument concept in developing and controlling the measurement setup for LFNS experiments. An example of a noise map obtained for polymer thick-film resistors (PTFRs), made of commercial compositions, for temperature range 77 K - 300 K has been shown. The experiments proved that 1/f noise caused by resistance fluctuations is the dominant noise component in the studied samples. However, the obtained noise map revealed also thermally activated noise sources. Furthermore, parameters describing noise properties of resistive materials and components have been introduced and calculated using data from LFNS. The results of the work may be useful for comparison of noise properties of different resistive materials, giving also directions for improvement of thick-film technology in order to manufacture reliable, low-noise and stable PTFRs.

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14

Kim, Jungsuk, Kyeongjin Kim, Sun-Ho Choe, and Hojong Choi. "Development of an Accurate Resonant Frequency Controlled Wire Ultrasound Surgical Instrument." Sensors 20, no. 11 (May 28, 2020): 3059. http://dx.doi.org/10.3390/s20113059.

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Our developed wire ultrasound surgical instrument comprises a bolt-clamped Langevin ultrasonic transducer (BLUT) fabricated by PMN-PZT single crystal material due to high mechanical quality factor and electromechanical coupling coefficient, a waveguide in the handheld instrument, and a generator instrument. To ensure high performance of wire ultrasound surgical instruments, the BLUT should vibrate at an accurate frequency because the BLUT’s frequency influences hemostasis and the effects of incisions on blood vessels and tissues. Therefore, we implemented a BLUT with a waveguide in the handheld instrument using a developed assembly jig process with impedance and network analyzers that can accurately control the compression force using a digital torque wrench. A generator instrument having a main control circuit with a low error rate, that is, an output frequency error rate within ±0.5% and an output voltage error rate within ±1.6%, was developed to generate the accurate frequency of the BLUT in the handheld instrument. In addition, a matching circuit between the BLUT and generator instrument with a network analyzer was developed to transfer displacement vibration efficiently from the handheld instrument to the end of the waveguide. Using the matching circuit, the measured S-parameter value of the generator instrument using a network analyzer was −24.3 dB at the resonant frequency. Thus, our proposed scheme can improve the vibration amplitude and accuracy of frequency control of the wire ultrasound surgical instrument due to developed PMN-PZT material and assembly jig process.

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15

Zuo, Jiansheng, and Xiaonan Zheng. "Research on Calibration System of Low Frequency Electric Field Measuring Instrument." IOP Conference Series: Materials Science and Engineering 768 (March 31, 2020): 062109. http://dx.doi.org/10.1088/1757-899x/768/6/062109.

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16

Acquaviva, Andrew A., and Stephen C. Thompson. "Underwater low frequency acoustic projector based on a musical instrument design." Journal of the Acoustical Society of America 134, no. 5 (November 2013): 4093. http://dx.doi.org/10.1121/1.4830948.

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17

Mennella, A., M. Bersanelli, R. C. Butler, F. Cuttaia, O. D'Arcangelo, R. J. Davis, M. Frailis, et al. "Planckpre-launch status: Low Frequency Instrument calibration and expected scientific performance." Astronomy and Astrophysics 520 (September 2010): A5. http://dx.doi.org/10.1051/0004-6361/200912849.

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18

Bersanelli, M., N. Mandolesi, R. C. Butler, A. Mennella, F. Villa, B. Aja, E. Artal, et al. "Planckpre-launch status: Design and description of the Low Frequency Instrument." Astronomy and Astrophysics 520 (September 2010): A4. http://dx.doi.org/10.1051/0004-6361/200912853.

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19

Valenziano, L., M. Sandri, G. Morgante, C. Burigana, M. Bersanelli, R. C. Butler, F. Cuttaia, et al. "The low frequency instrument on-board the Planck satellite: Characteristics and performance." New Astronomy Reviews 51, no. 3-4 (March 2007): 287–97. http://dx.doi.org/10.1016/j.newar.2006.11.030.

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20

Morgan, F. D., T. R. Madden, and B. R. Bennett. "An instrument system for low-frequency (10−3–103 Hz) impedance measurements." IEEE Transactions on Instrumentation and Measurement IM-35, no. 3 (September 1986): 287–92. http://dx.doi.org/10.1109/tim.1986.6499211.

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21

Villa, F., L. Terenzi, M. Sandri, P. Meinhold, T. Poutanen, P. Battaglia, C. Franceschet, et al. "Planckpre-launch status: Calibration of the Low Frequency Instrument flight model radiometers." Astronomy and Astrophysics 520 (September 2010): A6. http://dx.doi.org/10.1051/0004-6361/200912860.

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22

Mandolesi, N., C. Burigana, A. Gruppuso, P. Procopio, and S. Ricciardi. "An overview of the Planck mission." Proceedings of the International Astronomical Union 6, S274 (September 2010): 268–73. http://dx.doi.org/10.1017/s1743921311007101.

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AbstractThis paper provides an overview of the ESA Planck mission and its scientific promises. Planck is equipped with a 1.5–m effective aperture telescope with two actively-cooled instruments observing the sky in nine frequency channels from 30 GHz to 857 GHz: the Low Frequency Instrument (LFI) operating at 20 K with pseudo-correlation radiometers, and the High Frequency Instrument (HFI) with bolometers operating at 100 mK. After the successful launch in May 2009, Planck has already mapped the sky twice (at the time of writing this review) with the expected behavior and it is planned to complete at least two further all-sky surveys. The first scientific results, consisting of an Early Release Compact Source Catalog (ERCSC) and in about twenty papers on instrument performance in flight, data analysis pipeline, and main astrophysical results, will be released on January 2011. The first publications of the main cosmological implications are expected in 2012.

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23

André, R., F. Lefeuvre, F. Simonet, and U. S. Inan. "A first approach to model the low-frequency wave activity in the plasmasphere." Annales Geophysicae 20, no. 7 (July 31, 2002): 981–96. http://dx.doi.org/10.5194/angeo-20-981-2002.

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Abstract. A comprehensive empirical model of waves is developed in the objective to simulate wave-particle interactions involved in the loss and acceleration of radiation belt electrons. Three years of measured magnetic wave field components from the Plasma Wave Instrument on board the DE-1 satellite are used to model the amplitude spectral density of the magnetic wave field of each type of emission observed in the equatorial regions of the plasmasphere: VLF transmitter emissions, chorus emissions, plasmaspheric hiss emissions and equatorial emissions below ~ 200 Hz. Each model is a function of the wave frequency f , the MLT, L and Mlat parameters, and the Kp values. The performances of the plasmaspheric hiss and chorus models are tested on amplitude spectra recorded on board the OGO-5 and GEOS-1 satellites.Key words. Magnetospheric physics (plasmasphere; plasma waves and instabilities; instruments and techniques)

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24

Lynch-Aird, Nicolas, and Jim Woodhouse. "Frequency Measurement of Musical Instrument Strings Using Piezoelectric Transducers." Vibration 1, no. 1 (January 13, 2018): 3–19. http://dx.doi.org/10.3390/vibration1010002.

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The use of a piezoelectric transducer to monitor the tuning of a musical instrument string has been investigated. It has been shown that the transverse resonance frequencies of the string can be identified by electrical measurements on a low-cost actuator/sensor, sufficiently discreetly to be done during a performance. This frequency measurement approach can be used as the basis for a tuning control mechanism to maintain a musical instrument string at the required pitch, without it having to be plucked or played. Such a system would be of direct benefit to harp players in particular, who have no other means to adjust a mistuned string during a performance. Some of the practical issues and implications of adding such a tuning control system to the harp are considered.

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25

Zhang, De Sheng, Guo Tian He, Ming Li, and Li Song. "The Characteristic Analysis of Double Vibration Isolation Model Based on MRF and Piezoceramics." Applied Mechanics and Materials 246-247 (December 2012): 1309–13. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.1309.

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with the rapid development of ultraprecise process technology, the precision of instrument is being improved fast. Then instruments are more sensitive to the vibration of environment. This paper took advantage of the controlled character of MRF’s shear force, using actuators made of PZT,and put forward the double vibration isolation model based on MRF and piezoceramics. Through the theoretical analysis we arrival at a conclusion that the model has a good Isolation effect on both high frequency vibration and low frequency vibration especially ultralow frequency vibration.

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26

Mennella, A., M. Bersanelli, R. C. Butler, A. Curto, F. Cuttaia, R. J. Davis, J. Dick, et al. "Planckearly results. III. First assessment of the Low Frequency Instrument in-flight performance." Astronomy & Astrophysics 536 (December 2011): A3. http://dx.doi.org/10.1051/0004-6361/201116480.

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27

Liu, Hanli. "Low-cost frequency-domain photon migration instrument for tissue spectroscopy, oximetry, and imaging." Optical Engineering 36, no. 5 (May 1, 1997): 1562. http://dx.doi.org/10.1117/1.601354.

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28

Jones, D. L., and K. W. Weiler. "Low Frequency Radio Astronomy from the Moon." Highlights of Astronomy 11, no. 2 (1998): 988–89. http://dx.doi.org/10.1017/s1539299600019389.

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AbstractThe radio sky at frequencies of several MHz and below is essentially unexplored with high angular resolution due to refraction and opacity in the Earth’s ionosphere. An interferometer array in space providing arcminute resolution images would allow a wide range of problems in solar, planetary, galactic, and extragalactic astronomy to be attacked. These include the evolution of solar and planetary radio bursts, interplanetary and interstellar scintillation, the distribution of low energy cosmic rays and diffuse ionized hydrogen in our galaxy, the determination of spectral turnover frequencies and magnetic field strengths in galactic and extragalactic radio sources, searches for “fossil” radio galaxies which are no longer detectable by high frequency surveys, and searches for new sources of coherent radio emission. In addition, it is likely that unexpected objects and emission processes will be discovered by such an instrument, as has often happened when high resolution observations first become possible in a new spectral region. The Moon can provide shielding from terrestrial interference (and from the Sun half of the time) and consequently the lunar farside surface offers an ideal site of a low frequency radio array.

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29

Narasimha, D., and S. M. Chitre. "Probes of Low Surface Brightness Galaxies through Low Frequency Spectroscopy with GMRT." Symposium - International Astronomical Union 199 (2002): 110–13. http://dx.doi.org/10.1017/s0074180900168652.

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Low Surface Brightness galaxies (LSBs) may well constitute an important component of the Universe and a good fraction of baryons may even be locked up in their gravitational potential. Existence of such massive objects was predicted from an investigation of gravitational lens systems more than a decade ago (Narasimha & Chitre, 1989). There are more compelling reasons for believing their universality based on the of the analysis of the images around the cusp caustics in some of the well-studied lenses. A complete sample of the mass, size and rotation velocity of LSBs in our neighbourhood, as well as in a limited volume at a larger redshift will be important for estimation of power spectrum as well as evolution of structures in the Universe. The GMRT type instrument is ideally suited for detection and study of the LSBs. We expect to detect 21 cm emission from around 2 to 10 LSBs per beam of GMRT dish at the level of 5 mJy flux with a survey covering 30 Mhz bandwidth, if their line width is of the order of 30 km/sec.

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30

Commane, R., K. Seitz, C. S. E. Bale, W. J. Bloss, J. Buxmann, T. Ingham, U. Platt, D. Pöhler, and D. E. Heard. "Iodine monoxide at a clean marine coastal site: observations of high frequency variations and inhomogeneous distributions." Atmospheric Chemistry and Physics Discussions 11, no. 2 (February 8, 2011): 4533–68. http://dx.doi.org/10.5194/acpd-11-4533-2011.

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Abstract. The first in situ point observations of iodine monoxide (IO) at a clean marine site were made using a laser-induced fluorescence instrument deployed at Mace Head, Ireland in August 2007. IO mixing ratios of up to 49.8 pptv (1 s) were observed at day-time low tide, well in excess of previous observed spatially-averaged maxima. A strong anti-correlation of IO with tide height was evident and the high time resolution of the observations showed IO peaked in the hour after low tide. The temporal delay in IO peak compared to low tide has not been observed previously but coincides with the time of peak aerosol number previously observed at Mace Head. A long path-differential optical absorption spectroscopy instrument (with a 2 × 6.8 km folded path across Roundstone Bay) was also based at the site for 3 days during the point measurement observation period. Both instruments show similar temporal trends but the point measurements of IO are a factor of ~6–10 times greater than the spatially averaged IO mixing ratios, providing empirical evidence of the presence of inhomogeneities in the IO mixing ratio near the intertidal region.

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31

Boudjada, Mohammed Y., Patrick H. M. Galopeau, Sami Sawas, Valery Denisenko, Konrad Schwingenschuh, Helmut Lammer, Hans U. Eichelberger, Werner Magnes, and Bruno Besser. "Low-altitude frequency-banded equatorial emissions observed below the electron cyclotron frequency." Annales Geophysicae 38, no. 3 (June 24, 2020): 765–74. http://dx.doi.org/10.5194/angeo-38-765-2020.

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Abstract. The ICE (Instrument Champ Électrique) experiment on board the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite recorded frequency-banded wave emissions below the electron cyclotron frequency, with band spacing ≳ frequency low-hybrid resonance, in the vicinity of the magnetic equatorial plane. Those radiations were observed in the beginning of the year 2010 on the night side of Earth and rarely on the day side. We distinguish two components: one appears as frequency bands continuous in time between a few kilohertz and up to 50 kHz, and the other one is from 50 to 800 kHz. The first component exhibits positive and negative frequency drift rates in the Southern Hemisphere and Northern Hemisphere, at latitudes between 40 and 20∘. The second one displays multiple spaced frequency bands. Such bands mainly occur near the magnetic equatorial plane with a particular enhancement of the power level when the satellite latitude is close to the magnetic equatorial plane. We show in this study the similarities and the discrepancies between the non-free-space DEMETER frequency-banded emissions and the well-known free-space terrestrial kilometric radiation. The hollow cones of the DEMETER frequency-banded wave emissions are oriented towards Earth's ionosphere. We suggest that the source region is localized in regions poleward of the plasmapause where the ratio of the plasma frequency to gyro-frequency is smaller than one.

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32

Zhang, Yinglu, Zhenzhu Xi, Xingpeng Chen, Honglan Wei, Long Huang, and Wei Xiao. "Design of Analog Front-end Circuit for Audio-frequency Magnetotelluric Instrument." Journal of Environmental and Engineering Geophysics 23, no. 3 (September 2018): 305–18. http://dx.doi.org/10.2113/jeeg23.3.305.

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High-performance audio-frequency magnetotelluric (AMT) instrument is one means of obtaining high-quality electromagnetic (EM) data. To improve the ability of AMT system to obtain high-quality data, this paper presents a design for a high-performance analog front-end circuit for AMT instrument. It mainly consists of the input protection, preamplifier, passive high pass filter, power frequency notch filter, programmable amplifier, and active low pass filter. In addition, this paper proposes a design of low-noise, high-performance preamplifier, which improves the common-mode rejection ratio (CMRR) of analog front-end circuit and effectively enhances the signal-to-noise ratio (SNR) of the circuit. The front-end circuit utilized two-stage twin-T notch filter to effectively suppress the strong interference of fundamental component of power frequency. Also, it used signal relays to control circuit gain and selection of cutoff frequency of anti-aliasing filter, resulting in the improvement of the capability of the analog-to-digital Converter (ADC) to distinguish weak EM signal. The measured results of the electric field and magnetic field channel showed that: 1) The circuit works in frequency range of 1 Hz∼100 kHz; 2) The CMRR values of the preamplifier of electric field channel at low frequencies (1 Hz∼1 kHz) are 111 dB and 97 dB when the gains are 20 dB and 6 dB respectively; 3) The maximum attenuation fundamental power frequency can reach −39.46 dB and −39.04 dB respectively; 4) The total harmonic distortion rate at 1 kHz is 0.022% and 0.029% respectively; 5) The input noise levels of electric field channel are 12.67nV / [Formula: see text] @10Hz and 8.15V / [Formula: see text] @1kHz, while the input noise levels of magnetic field channel are 8.97nV / [Formula: see text] @10Hz and 6.16V / [Formula: see text] @1kHz; and 6) In conclusion, the analog front-end circuit is superior to meet the requirements of the AMT methods, and provides a useful reference for the development of AMT instrument.

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33

Wan, Cai, Wei He, Pan Guo, Jiamin Wu, Yucheng He, and Zheng Xu. "A compact magnetic resonance system with inside-out sensor for soil moisture measurement." Measurement Science and Technology 33, no. 7 (April 4, 2022): 075902. http://dx.doi.org/10.1088/1361-6501/ac6000.

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Abstract Accurate measurement of soil moisture parameters plays a vital role in promoting agricultural production. Nuclear magnetic resonance (NMR) measuring instruments have become increasingly compact, especially in low field applications. However, NMR soil moisture measurement instruments still have problems with portability. We report on a compact NMR measuring instrument that focuses on the circuit’s design and construction. The instrument includes an inside-out sensor, NMR spectrometer, radio frequency power amplifier, low-noise preamplifier, and duplexer. They are integrated into a slim 3D-printed cylinder. The integrated NMR instrument is portable and user-friendly and can reduce the influence of nonideal factors, such as transmission line effects and electromagnetic interference. We conducted different soil moisture experiments with the prototype using Carr–Purcell–Meiboom–Gill pulse sequence to obtain the corresponding transverse relaxation time (T 2) decay curves. Then, the T 2 1D spectrum distributions were obtained by inverse Laplace transformation. Finally, the results reveal that the area of long T 2 component decreases as the soil moisture content decreases.

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34

Hartogh, P., and Ya A. Ilyushin. "A passive low frequency instrument for radio wave sounding the subsurface oceans of the Jovian icy moons: An instrument concept." Planetary and Space Science 130 (October 2016): 30–39. http://dx.doi.org/10.1016/j.pss.2016.05.008.

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35

Burigana, C., M. Sandri, F. Villa, D. Maino, R. Paladini, C. Baccigalupi, M. Bersanelli, and N. Mandolesi. "Trade-off between angular resolution and straylight contamination in the PLANCK Low Frequency Instrument." Astronomy & Astrophysics 428, no. 1 (November 23, 2004): 311–25. http://dx.doi.org/10.1051/0004-6361:20041403.

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36

Sandri, M., F. Villa, R. Nesti, C. Burigana, M. Bersanelli, and N. Mandolesi. "Trade-off between angular resolution and straylight contamination in the PLANCK Low Frequency Instrument." Astronomy & Astrophysics 428, no. 1 (November 23, 2004): 299–310. http://dx.doi.org/10.1051/0004-6361:20041435.

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37

Urusovskiĭ, I. A. "Rotating vibratory system as an instrument for measuring low-frequency vibration and gravitational acceleration." Acoustical Physics 52, no. 4 (July 2006): 477–80. http://dx.doi.org/10.1134/s1063771006040166.

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38

Doody, S. G., N. Hughes, L. Ramio‐Tomas, E. Mak, D. G. Muff, and M. R. Nottingham. "Low‐frequency synthetic aperture radar data‐dome collection with the Bright Sapphire II instrument." Electronics Letters 53, no. 15 (July 2017): 981–83. http://dx.doi.org/10.1049/el.2017.1478.

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39

Commane, R., K. Seitz, C. S. E. Bale, W. J. Bloss, J. Buxmann, T. Ingham, U. Platt, D. Pöhler, and D. E. Heard. "Iodine monoxide at a clean marine coastal site: observations of high frequency variations and inhomogeneous distributions." Atmospheric Chemistry and Physics 11, no. 13 (July 13, 2011): 6721–33. http://dx.doi.org/10.5194/acp-11-6721-2011.

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Abstract. The first in situ point observations of iodine monoxide (IO) at a clean marine site were made using a laser-induced fluorescence instrument deployed at Mace Head, Ireland in August 2007. IO mixing ratios of up to 49.8 pptv (equivalent to pmol mol−1; 1 s average) were observed at day-time low tide, well in excess of previous observed spatially-averaged maxima. A strong anti-correlation of IO mixing ratios with tide height was evident and the high time resolution of the observations showed IO peaked in the hour after low tide. The temporal delay in peak IO compared to low tide has not been observed previously but coincides with the time of peak aerosol number previously observed at Mace Head. A long path-differential optical absorption spectroscopy instrument (with a 2 × 6.8 km folded path across Roundstone Bay) was also based at the site for 3 days during the point measurement observation period. Both instruments show similar temporal trends but the point measurements of IO are a factor of ~6–10 times greater than the spatially averaged IO mixing ratios, providing direct empirical evidence of the presence of inhomogeneities in the IO mixing ratio near the intertidal region.

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Wang, Lin Sheng, Ying Ma, and Xiao Zhi Wang. "Design and Implementation of Portable Intelligent LCF Measuring Instrument." Applied Mechanics and Materials 539 (July 2014): 75–78. http://dx.doi.org/10.4028/www.scientific.net/amm.539.75.

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In view of it is often needed to measure the value of the inductance capacitance and signal frequency in the welding and the debugging process of the electronic circuit, specialized equipment due to the huge volume of expensive equipment which is difficult to measure, we use SCM to design a portable measuring instrument which have low cost and can measure the value of inductance and capacitance, as well as signal frequency. It can meet the demand of precision after testing, so as to reach requirements for measuring instrument.

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Pace, Charles F., Steven M. Thornberg, and Jon R. Maple. "Luminescence Instrument for the Acquisition of Low-Temperature Fluorescence and Phosphorescence Spectra." Applied Spectroscopy 42, no. 5 (July 1988): 891–96. http://dx.doi.org/10.1366/0003702884428941.

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An inexpensive, simple (but highly automated) instrument for acquiring high-resolution fluorescence and phosphorescence spectra of polycyclic aromatic hydrocarbons (PAHs) is described. Fluorescence and phosphorescence signals are processed by gated integration and photon counting, respectively. The instrument can be used to acquire excitation as well as emission spectra in both the frequency and time domain. In addition, a method for measuring single and double exponential phosphorescence decay times is presented. Decay times ranging from 0.3 ms to 300 ms were measured for several naphthalene derivatives, with a precision of ∼10%. The primary advantages of this instrument are high sensitivity, high selectivity, wide linear dynamic ranges, and a versatile range of applications.

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Zhu, Wu, Yong Wang, Chao Jiang, and Jia Min Zhu. "Design of Detection System for Residual Voltage Based on SOPC." Applied Mechanics and Materials 241-244 (December 2012): 180–85. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.180.

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In accordance with the relevant safety standard requirements for electrical equipment, this thesis proposes a residual voltage detection method with high accuracy and low power consumption . The power frequency synchronization signal is obtained by the measuring instrument with the zero-crossing detection circuit used. In the power frequency AC peak moment the measured instrument's power is cut off and the measured equipment's residual voltage is sampled by the input circuit with the high input impedance. Under the control of the NIOSII, the on-line detection of power-down residual voltage of equipment after the 1second and 10seconds is realized with the high speed sampling /hold-circuit and high precision ADC module used. The experimental result shows that the measuring instrument has good stability, with measurement accuracy up to 0.506%, meeting the measurement requirements.

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Tian, Tian, Wu Jian, and Nie Li. "Measurement of Amplifier Open-Loop Amplitude Frequency Characteristics Based on Virtual Instrument." Applied Mechanics and Materials 475-476 (December 2013): 16–22. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.16.

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In the electronic measurement field, how to measure the open-loop amplitude frequency characteristics of the amplifier automatically is a question to be overcame. And now , the system ,which under the integrated development environment that the virtual instrument software LabVIEW provides, to measure the open-loop amplitude frequency characteristics of the amplifier is developed by combining the modern electronic measurement technology and computer data processing technology. The virtual signal generator which is based on the data acquisition card, signal acquisition, correlation analysis, frequency response analysis, etc is included in the system. This design mainly includes the hardware circuit and the software program. The hardware circuit consists of the low noise preamplifier, measured operational amplifier, data acquisition card, power supply, computer, etc. Modular design is adopted in the software part, which includes the design of soft panel, signal generation, collection and analysis module. The advantages of the virtual instrument, such as the digital signal processing, waveform data automatic storage, graphical programming, are fully used in the modern electronic measurement. Simple structure, low cost, high level of test automation are its characteristics.

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Nishiyama, Akira, and Erisa Tsuchida. "Relationship Between Wind Instrument Playing Habits and Symptoms of Temporomandibular Disorders in Non-Professional Musicians." Open Dentistry Journal 10, no. 1 (August 22, 2016): 411–16. http://dx.doi.org/10.2174/1874210601610010411.

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Background: In this study, we focused on the habits of wind instrumentalists as well as the presence of playing instruments, and investigated associations between the risk of temporomandibular disorders (TMD) and playing wind instruments in non-professional musicians. Material and Methods: Seventy-two non-professional players of wind instruments (instrument group) (mean(SD), 20.0(1.1) y; 42 women) and 66 non-players (control group) (22.0(2.6) y; 45 women) participated in this study. Factors were investigated using questionnaires (a screening questionnaire for TMD, instrument playing habits, years of experience, and time played per day). Result: The prevalence of a high risk of TMD was not significantly different between the instrument group (29.2%) and control group (21.2%). In the instrument group, the frequency of subjects who felt mouthpiece pressure in the high risk of TMD group (47.6%) was significantly greater than that in the low risk of TMD group (21.6%). Mouthpiece pressure was found to be a significant factor contributing to a high risk of TMD (odds ratio, 3.31; 95% CI, 1.12–9.79). Conclusion: This study suggests that pressure from the mouthpiece was one of the contributing factors related to a high risk of TMD in non-professional wind instrument players.

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Hamza, Veton, Bojan Stopar, Tomaž Ambrožič, and Oskar Sterle. "Performance Evaluation of Low-Cost Multi-Frequency GNSS Receivers and Antennas for Displacement Detection." Applied Sciences 11, no. 14 (July 20, 2021): 6666. http://dx.doi.org/10.3390/app11146666.

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Low-cost Global Navigation Satellite System (GNSS) receivers are currently used in various engineering applications. These low-cost devices are regarded as suitable sensors for applications in areas with a high risk of instrument damage. The main objectives of this research were to identify the size of displacements that can be detected in relative and absolute positioning modes by low-cost GNSS instruments and to compare the results of selected antennas. Additionally, geodetic and low-cost GNSS instruments were compared in the level of observations. For this study, low-cost SimpleRTK2B V1 boards, which house ZED-F9P GNSS chips, and three low-cost antennas, namely, Survey, Tallysman TW3882, and Survey Calibrated, were selected. While antenna calibration parameters are known for the last antenna, this is not the case for the first two. For testing purposes, a geodetic network consisting of four points was established; horizontal and vertical movements were imposed by a special mechanism with high accuracy. In relative positioning mode, the results indicate that the Survey Calibrated antenna can detect horizontal and vertical displacements with sizes of 4 mm, and 6 mm, respectively. In the detection of horizontal displacements, the performance of the Survey antenna was not as good as that of Tallysman, and the sizes of detected displacements were 6 mm and 4 mm for the first, and second antennas, respectively. Vertical displacements of 9 mm were detected using both Survey and Tallysman antennas. In absolute positioning mode, Survey Calibrated also had better performance than the Tallysman antenna, and spatial displacements of 20 mm or greater were detected by low-cost GNSS instruments. The observations made with low-cost and geodetic GNSS instruments were compared, and the latter showed better performance. However, the differences in cycle slips and the noise of phase observations were inferior. Considering their cost and proven performance, it can be concluded that such sensors can be considered for setting up a highly accurate but low-cost geodetic monitoring system.

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Maya, Paulina, Belén Calvo, María Teresa Sanz-Pascual, and Javier Osorio. "Low Cost Autonomous Lock-In Amplifier for Resistance/Capacitance Sensor Measurements." Electronics 8, no. 12 (November 26, 2019): 1413. http://dx.doi.org/10.3390/electronics8121413.

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This paper presents the design and experimental characterization of a portable high-precision single-phase lock-in instrument with phase adjustment. The core consists of an analog lock-in amplifier IC prototype, integrated in 0.18 µm CMOS technology with 1.8 V supply, which features programmable gain and operating frequency, resulting in a versatile on-chip solution with power consumption below 834 µW. It incorporates automatic phase alignment of the input and reference signals, performed through both a fixed −90° and a 4-bit digitally programmable phase shifter, specifically designed using commercially available components to operate at 1 kHz frequency. The system is driven by an Arduino YUN board, thus overall conforming a low-cost autonomous signal recovery instrument to determine, in real time, the electrical equivalent of resistive and capacitive sensors with a sensitivity of 16.3 µV/Ω @ εrS < 3% and 37 kV/F @ εrS < 5%, respectively.

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Frank, William B., and Emily E. Brodsky. "Daily measurement of slow slip from low-frequency earthquakes is consistent with ordinary earthquake scaling." Science Advances 5, no. 10 (October 2019): eaaw9386. http://dx.doi.org/10.1126/sciadv.aaw9386.

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Slow slip transients on faults can last from seconds to months and stitch together the earthquake cycle. However, no single geophysical instrument is able to observe the full range of slow slip because of bandwidth limitations. Here, we connect seismic and geodetic data from the Mexican subduction zone to explore an instrumental blind spot. We establish a calibration of the daily median amplitude of the seismically recorded low-frequency earthquakes to the daily geodetically recorded moment rate of previously established slow slip events. This calibration allows us to use the precise evolution of low-frequency earthquake activity to quantitatively measure the moment of smaller, subdaily slip events that are unresolvable by geodesy alone. The resulting inferred slow slip moments scale with duration and inter-event time like ordinary earthquakes. These new quantifications help connect slow and fast events in a broad spectrum of transient slip and suggest that slow slip events behave much like ordinary earthquakes.

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Wang, Hong Wei, Xiao Ni Wang, Xu Tian, Gai Hong Du, Yang Meng Tian, Qi Mu Su Rong, and Wen Kai Zhang. "Software and Hardware Design of a Acoustic Fault Detecting Instrument." Applied Mechanics and Materials 432 (September 2013): 246–52. http://dx.doi.org/10.4028/www.scientific.net/amm.432.246.

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This paper is about a kind of instrument which can detect the fault object by acoustic sensor detecting the object Surface acoustic signals, through the analysis of the acoustic signal of the intensity and frequency content, so determining the object if abnormal conditions occur. Design by using Piezoelectricity material as the sensing head, the signal processing circuit is based on SH79F32 microcontroller as the core, the single-chip microcomputer, integration with ADC, the analog signal from the sensor to convert them into digital signals, in the procedure, carries on processing to the signal frequency components, filter out low-frequency components, acoustic signal was finally measured on a screen display. including hardware design, production, processing, software programming, to obtain the acoustic fault detector, and to test its performance, results show successful.

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Vorob’ev, M. D., and D. N. Yudaev. "Mobile Adaptable Measuring Instrument of Low-Frequency Noise Characteristics in Diagnostics of Vacuum Tube Devices." Measurement Techniques 60, no. 7 (October 2017): 731–35. http://dx.doi.org/10.1007/s11018-017-1262-8.

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Chanerley, A. A., and N. A. Alexander. "Obtaining estimates of the low-frequency ‘fling’, instrument tilts and displacement timeseries using wavelet decomposition." Bulletin of Earthquake Engineering 8, no. 2 (August 14, 2009): 231–55. http://dx.doi.org/10.1007/s10518-009-9150-5.

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