The Experts below are selected from a list of 33084 Experts worldwide ranked by ideXlab platform
L J Leblanc - One of the best experts on this subject based on the ideXlab platform.
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atomic microwave to optical signal transduction via magnetic field coupling in a resonant microwave cavity
Applied Physics Letters, 2020Co-Authors: Andrei Tretiakov, C A Potts, T S Lee, M J Thiessen, J P Davis, L J LeblancAbstract:Atomic vapors offer many opportunities for manipulating electromagnetic signals across a broad range of electromagnetic spectra. Here, a microwave signal with an Audio Frequency modulation encodes information in an optical signal by exploiting an atomic microwave-to-optical double resonance and magnetic-field coupling that is amplified by a resonant high-Q microwave cavity. Using this approach, Audio signals are encoded as amplitude or Frequency modulations in a GHz carrier, transmitted through a cable or over free space, demodulated through cavity-enhanced atom-microwave interactions, and, finally, optically detected to extract the original information. This atom-cavity signal transduction technique provides a powerful means by which to transfer information between microwave and optical fields, all using a relatively simple experimental setup without active electronics.
Andrei Tretiakov - One of the best experts on this subject based on the ideXlab platform.
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atomic microwave to optical signal transduction via magnetic field coupling in a resonant microwave cavity
Applied Physics Letters, 2020Co-Authors: Andrei Tretiakov, C A Potts, T S Lee, M J Thiessen, J P Davis, L J LeblancAbstract:Atomic vapors offer many opportunities for manipulating electromagnetic signals across a broad range of electromagnetic spectra. Here, a microwave signal with an Audio Frequency modulation encodes information in an optical signal by exploiting an atomic microwave-to-optical double resonance and magnetic-field coupling that is amplified by a resonant high-Q microwave cavity. Using this approach, Audio signals are encoded as amplitude or Frequency modulations in a GHz carrier, transmitted through a cable or over free space, demodulated through cavity-enhanced atom-microwave interactions, and, finally, optically detected to extract the original information. This atom-cavity signal transduction technique provides a powerful means by which to transfer information between microwave and optical fields, all using a relatively simple experimental setup without active electronics.
Jun Yang - One of the best experts on this subject based on the ideXlab platform.
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Estimating ear canal geometry and eardrum reflection coefficient from ear canal input impedance
2016 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2016Co-Authors: Huiqun Deng, Jun YangAbstract:Based on the signal model of ear canals, a novel method for solving the inverse problem of estimating the unique solution of the ear canal area function and the eardrum reflection coefficient given the acoustic input impedance at the entrance of an ear canal is presented. Up-sampling techniques to improve the accuracy of the estimates are also presented. The performance of this method and factors affecting the accuracy of the estimates are investigated via simulations. It is found that the accuracy of the estimates is limited by the measurement bandwidth of the given ear canal input impedance. In the Audio Frequency range, the estimates obtained approximate well to the true ones. To obtain more accurate estimates, a wider measurement bandwidth of the ear canal input impedance is required.
Hui Zhang - One of the best experts on this subject based on the ideXlab platform.
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an acoustic metamaterial composed of multi layer membrane coated perforated plates for low Frequency sound insulation
Applied Physics Letters, 2015Co-Authors: Zhe Chen, Jin Ding, Xiaojuan Li, Shuyi Zhang, Hui ZhangAbstract:Insulating against low-Frequency sound (below 500 Hz) remains challenging despite the progress that has been achieved in sound insulation and absorption. In this work, an acoustic metamaterial based on membrane-coated perforated plates is presented for achieving sound insulation in a low-Frequency range, even covering the lower Audio Frequency limit, 20 Hz. Theoretical analysis and finite element simulations demonstrate that this metamaterial can effectively block acoustic waves over a wide low-Frequency band regardless of incident angles. Two mechanisms, non-resonance and monopolar resonance, operate in the metamaterial, resulting in a more powerful sound insulation ability than that achieved using periodically arranged multi-layer solid plates.
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An acoustic dual filter in the Audio frequencies with two local resonant systems
Applied Physics Letters, 2014Co-Authors: Z. G. Liu, Shuyi Zhang, Hui Zhang, Li FanAbstract:We report an acoustic dual filter to realize the sound regulation in the Audio Frequency range, in which resonant vibrations of two membrane-air and metal-elastomer systems generate two sound transmission peaks and a sound blocking below 3000 Hz. The local vibrational profiles manifest that the transmission peak at lower Frequency is mainly dependent on the resonant vibration of the membrane-air system, and the coupling vibrations of two systems generate the blocking Frequency and transmission peak at higher Frequency. Importantly, two transmission peaks can be controlled independently. It is feasible to realize the acoustic device in sound shield and dual filters.
David W Graham - One of the best experts on this subject based on the ideXlab platform.
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a low power and high precision programmable analog filter bank
IEEE Transactions on Circuits and Systems Ii-express Briefs, 2012Co-Authors: Brandon Rumberg, David W GrahamAbstract:Analog filter banks befit remote Audio- and vibration-sensing applications, which require Frequency analysis to be performed with low-power consumption and with moderate-to-high precision. The precision of a filter bank depends on both the signal-path precision (i.e., dynamic range) and also the parameter precision (e.g., accuracy of the center frequencies). This brief presents a new bandpass filter for Audio-Frequency filter banks and provides a procedure for designing this filter. The filter is used in a 16-channel filter bank which has been fabricated in a 0.35- CMOS process. This filter bank has a dynamic range exceeding 62 dB and consumes only 63.6 when biased for speech frequencies. The filter bank's parameters are set via floating-gate current sources. This brief shows how to use these floating gates to obtain a versatile filter bank that can be precisely reprogrammed to arbitrary filter spacings and Frequency weightings, with a parameter accuracy exceeding 99%.
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a low power magnitude detector for analysis of transient rich signals
IEEE Journal of Solid-state Circuits, 2012Co-Authors: Brandon Rumberg, David W GrahamAbstract:Magnitude detection, such as envelope detection or RMS estimation, is needed for many low-power signal-analysis applications. In such applications, the temporal accuracy of the magnitude detector is as important as its amplitude accuracy. We present a low-power Audio-Frequency magnitude detector that simultaneously achieves both high temporal accuracy and high amplitude accuracy. This performance is achieved by rectifying the signal with a high-ripple peak detector and then averaging this rectified signal with an adaptive-time-constant filter. The time constant of this filter decreases with increasing amplitude, enabling the filter to quickly respond on a short time scale to transients, while steady-state ripple is averaged on a longer time scale. The circuit has been fabricated in a 0.18 μm CMOS process and consumes only 1.1 nW-1.08 μW when tuned for operation from 20 Hz-20 kHz. It exhibits a dynamic range of 70 dB across typical speech frequencies.
