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Controlling Energy Radiations of Electromagnetic Waves via frequency coding Metamaterials

ADVANCED SCIENCE 2017年第9期4卷 1700098页

作者： Wu, Haotian Liu, Shuo Wan, Xiang Zhang, Lei Wang, Dan Li, Lianlin Cui, Tie Jun Southeast Univ State Key Lab Millimeter Waves Nanjing 210096 Jiangsu Peoples R China Peking Univ Sch Elect Engn & Comp Sci Beijing 100871 Peoples R China

Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes. In this case, not only different phase responses of the unit cells are considered, but also different phase sensitivities are also required. Due to different frequency sensitivities of unit cells, two units with the same phase response at the initial frequency may have different phase responses at higher frequency. To describe the frequency coding property of unit cell, digitalized frequency sensitivity is proposed, in which the units are encoded with digits "0" and "1" to represent the low and high phase sensitivities, respectively. By this merit, two degrees of freedom, spatial coding and frequency coding, are obtained to control the EM energy radiations by a new class of frequency-spatial coding metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments.

关键词： energy radiations frequency coding metamaterials multiple controls phase sensitivity

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The Application of the Joint Range and Speed Estimation Method in Short-Range Radars Using Ultra-Wideband Signals with a Pseudo-Random frequency coding

The Application of the Joint Range and Speed Estimation Meth...

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Systems of Signals Generating and Processing in the Field of on Board Communications

作者： D. I. Sapronov I. V. Kamenskiy Moscow Aviation Institute (National Research University) Moscow Russia

ISBN: (数字)9781728147727

ISBN: (纸本)9781728147734

This article uses the previously presented method [1] of joint estimation of range and radial velocity in short-range radars using one ultra-wideband signal with discrete frequency coded waveform (DFCW). The core of the method is the use of the expression of the two-dimensional digital compression function of the output of the radar receiver ADC. The results of the practical implementation of this method are presented in a radar with a generation circuit using a phase-locked loop (PLL) generator, direct digital synthesis generator (DDS) and a quadrature modulator (IQ modulator). The results of the method are compared for signals with linear and pseudo-random frequency codes. The results of the method after using the calibration algorithm are presented.

关键词： Ultra-wideband signals discrete frequency coded waveform linear DFCW pseudo-random DFCW Ultra wideband technologies radar Pseudorandom frequency coding Height finding radar signals joint estimation direct digital synthesis CORING METHODS Speed Estimation RADIAL VELOCITY Phase locked loops

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Cochlear mechanisms of frequency and intensity coding .1. The place code for pitch

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HEARING RESEARCH 1997年第1-2期111卷 65-75页

作者： Chatterjee, M Zwislocki, JJ SYRACUSE UNIV INST SENSORY RESSYRACUSENY 13244

In the past, several researchers have reported a substantial shift in the peak of the tone-evoked excitation pattern toward the base of the cochlea following an increase in the SPL of the stimulating tone. Evidence for such peak shifts has been found in the responses of auditory nerve fibers, cochlear microphonics, and the responses of outer hair cells and supporting cells in the cochlea, as well as in basilar membrane vibration measurements, and indirectly, in psychophysical data. However, direct evidence for such a peak shift in inner hair cell (IHC) responses has been relatively sparse. If the peak shift is preserved in the information conveyed to the auditory nerve fibers by the IHCs, the classical 'place theory' for frequency coding in the cochlea requires modification. In this study, the nature and extent of the SPL-dependent peak shift is examined with the help of recordings in the IHCs and other cells of the organ of Corti in the 0.5-2.5 kHz region of the Mongolian gerbil cochlea. It is demonstrated that the peak shift is a universal phenomenon in the diverse cell types in this region of the cochlea. Most importantly, a large SPL-dependent peak shift is demonstrated in IHC responses. On the other hand, the recordings indicate that the apical cutoff of the spatial excitation pattern is SPL-independent. We conclude, therefore, that the place theory of pitch perception must be abandoned or at least modified.

关键词： cochlea hair cell peak shift pitch frequency coding

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A Solution to Harmonic frequency Problem: frequency and Phase coding-Based Brain-computer Interface

A Solution to Harmonic Frequency Problem: Frequency and Phas...

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International Joint Conference on Neural Networks (IJCNN)

作者： Wong, Chi Man Wang, Boyu Wan, Feng Mak, Peng Un Mak, Pui In Vai, Mang I. Univ Macau Dept Elect & Elect Engn Fac Sci & Technol Taipa Peoples R China

ISBN: (纸本)9781424496365

In this paper, we propose a modified visual stimulus generation method and feature detection algorithm to design a frequency and phase coding steady-state visual evoked potential (SSVEP) based brain-computer interface (BCI). By utilizing both frequency and phase information, we solve the harmonic frequency problem in our proposed SSVEP-BCI system. The offline experimental results show that the proposed feature detection algorithm can enhance the classification rate over 10% (from 69%+/- 12% to 82%+/- 8%) even though only one signal electrode is used and the harmonic frequencies (6367Hz, 13.33Hz, 8357Hz and 17.14Hz) are employed.

关键词： Joints Neural networks USA Councils brain-computer interfaces coding-based brain-computer interface encoding feature detection algorithm frequency 13.33 Hz frequency 17.14 Hz frequency 6.67 Hz frequency 8.57 Hz frequency coding harmonic frequency problem medical signal processing phase coding signal classification signal classification rate signal electrode steady-state visual evoked potential visual evoked potentials visual stimulus generation method

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Study on thick circuit decoding of resonant isolated frequency coding

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Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University 2005年第2期29卷 88-90页

作者： Sun, Wei Wei, Xue-Ye Sch. of Electron. and Info. Eng. Beijing Jiaotong Univ. Beijing 100044 China

The track circuit decoding of the resonant isolated frequency coding named UM2000 is studied in this paper. An advanced decoding method with low frequency acquired after frequency inspected is presented. And the simul... 详细信息

关键词： Decoding frequency acquired frequency coding frequency inspected

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Identification of neural firing patterns, frequency and temporal coding mechanisms in individual aortic baroreceptors

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FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2015年第AUGUST期9卷 108页

作者： Gu, Huaguang Pan, Baobao Tongji Univ Sch Aerosp Engn & Appl Mech Shanghai 200092 Peoples R China

In rabbit depressor nerve fibers, an on-off firing pattern, period-1 firing, and integer multiple firing with quiescent state were observed as the static pressure level was increased. A bursting pattern with bursts at the systolic phase of blood pressure, continuous firing, and bursting with burst at diastolic phase and quiescent state at systolic phase were observed as the mean level of the dynamic blood pressure was increased. For both static and dynamic pressures, the firing frequency of the first two firing patterns increased and of the last firing pattern decreased due to the quiescent state. If the quiescent state is disregarded, the spike frequency becomes an increasing trend. The instantaneous spike frequency of the systolic phase bursting, continuous firing, and diastolic phase bursting can reflect the temporal process of the systolic phase, whole procedure, and diastolic phase of the dynamic blood pressure signal, respectively. With increasing the static current corresponding to pressure level, the deterministic Hodgkin-Huxley (HH) model manifests a process from a resting state first to period-1 firing via a subcritical Hopf bifurcation and then to a resting state via a supercritical Hopf bifurcation, and the firing frequency increases. The on-off firing and integer multiple firing were here identified as noise-induced firing patterns near the subcritical and supercritical Hopf bifurcation points, respectively, using the stochastic HH model. The systolic phase bursting and diastolic phase bursting were identified as pressure-induced firings near the subcritical and supercritical Hopf bifurcation points, respectively, using an HH model with a dynamic signal. The firing, spike frequency, and instantaneous spike frequency observed in the experiment were simulated and explained using HH models. The results illustrate the dynamics of different firing patterns and the frequency and temporal coding mechanisms of aortic baroreceptor.

关键词： neural coding neural firing pattern frequency coding temporal coding Hopf bifurcation aortic baroreceptor blood pressure depolarization block

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Prestin derived OHC surface area reduction underlies age-related rescaling of frequency place coding

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HEARING RESEARCH 2022年 423卷 108406页

作者： Zhang, Yu Lin, Guotong Wang, Yi Xue, Na Lin, Xin Du, Tingting Xiong, Wei Song, Lei Shanghai Jiao Tong Univ Shanghai Peoples Hosp 9 Dept Otolaryngol Head & Neck Surg Sch Med Shanghai Peoples R China Shanghai Jiao Tong Univ Ear Inst Sch Med Shanghai Peoples R China Shanghai Key Lab Translat Med Ear & Nose Dis Shanghai Peoples R China Tsinghua Univ Sch Life Sci Beijing Peoples R China Tsinghua Univ McGovern Inst Brain Res Tsinghua Univ IDG Beijing Peoples R China Fudan Univ Shanghai Zhongshang Hosp Dept Otolaryngol Head & Neck Surg Sch Med Shanghai Peoples R China

Outer hair cells (OHC) are key to the mammalian cochlear amplifier, powered by the lateral membrane protein Prestin. In this study, we explored age-related OHC changes and how the changes affected hearing in mouse. OHC nonlinear membrane capacitance measurements revealed that, starting upon completion of postnatal auditory development, a continuous reduction of total Prestin in OHCs accompanied by a sig-nificant reduction in their cell surface area. Prestin's density is unaffected by Prestin level drop over the whole age range tested, suggesting that the OHC size reduction is Prestin-dependent. Stereocilia length in aged OHCs remained unchanged but the first row stereocilia on the aged inner hair cells (IHCs) were elongated. Distortion product otoacoustic emission (DPOAE) group delays became longer with aging, sug-gesting an apical shift in vibration on basilar membrane. Acoustic lesion experiments revealed an apical shift in damage place in old cochleae accompanied by a shallower progression in synaptic damage over a wider frequency range that was indicative of a broader frequency filter. Overall, these findings suggest that in aging cochlea, a shift in frequency place coding could occur due to the changes in cochlear active and passive *** article is part of the Special Issue Outer hair cell Edited by Joseph Santos-Sacchi and Kumar Navaratnam.(c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://***/licenses/by-nc-nd/4.0/ )

关键词： Aging Prestin Outer hair cell DPOAE group delay Cochlear mechanics frequency coding

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Metamaterials: Controlling Energy Radiations of Electromagnetic Waves via frequency coding Metamaterials (Adv. Sci. 9/2017)

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Advanced Science 2017年第9期4卷 n/a-n/a页

作者： Haotian Wu Shuo Liu Xiang Wan Lei Zhang Dan Wang Lianlin Li Tie Jun Cui State Key Laboratory of Millimeter Waves Southeast University Nanjing 210096 China School of Electronic Engineering and Computer Sciences Peking University Beijing 100871 China

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Electrical stimulation of the auditory nerve: The coding of frequency, the perception of pitch and the development of cochlear implant speech processing strategies for profoundly deaf people

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CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY 1996年第9期23卷 766-776页

作者： Clark, GM Special Research Centre for Human Communication Research Department of Otolaryngology The University of Melbourne The Co-operative Research Centre for Cochlear Implant Speech and Hearing Research and The Bionic Ear Institute Melbourne Victoria Australia

1. The development of speech processing strategies for multiple-channel cochlear implants has depended on encoding sound frequencies and intensities as temporal and spatial patterns of electrical stimulation of the auditory nerve fibres so that speech information of most importance for intelligibility could be transmitted, 2. Initial physiological studies showed that rate encoding of electrical stimulation above 200 pulses/s could not reproduce the normal response patterns in auditory neurons for acoustic stimulation in the speech frequency range above 200 Hz and suggested that place coding was appropriate for the higher frequencies, 3. Rate difference limens in the experimental animal were only similar to those for sound up to 200 Hz. 4. Rate difference limens in implant patients were similar to those obtained in the experimental animal. 5. Satisfactory rate discrimination could be made for durations of 50 and 100 ms, but not 25 ms, This made rate suitable for encoding longer duration suprasegmental speech information, but not segmental information, such as consonants, The rate of stimulation could also be perceived as pitch, discriminated at different electrode sites along the cochlea and discriminated for stimuli across electrodes, 6. Place pitch could be scaled according to the site of stimulation in the cochlea so that a frequency scale was preserved and it also had a different quality from rate pitch and was described as tonality, Place pitch could also be discriminated for the shorter durations (25 ms) required for identifying consonants, 7. The inaugural speech processing strategy encoded the second formant frequencies (concentrations of frequency energy in the mid frequency range of most importance for speech intelligibility) as place of stimulation, the voicing frequency as rate of stimulation and the intensity as current level, Our further speech processing strategies have extracted additional frequency information and coded this as place of stimulation,

关键词： auditory nerve cochlear implant electrical stimulation electrophysiology frequency coding psychophysics speech processing

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An Angle Insensitive Chipless Tag Using frequency Domain And Polarization coding 10

An Angle Insensitive Chipless Tag Using Frequency Domain And...

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IEEE 10th Asia-Pacific Conference on Antennas and Propagation (APCAP)

作者： Li, Sen Tian, Yijia Zhuang, Lu Ouyang, Jun Univ Elect Sci & Technol China Chengdu 611730 Peoples R China

ISBN: (纸本)9781665489546

In this paper, a ring chipless tag insensitive to the incident wave angle is proposed. The tag adopts the patch type frequency selective surface structure, the surface of the dielectric substrate is composed of three groups of rings. By designing the coding frequency band as the staggered arcs, designing the radius and radian of them, in addition extracting and processing the dual polarization Radar Cross Section(RCS), the frequency domain and polarization coding are realized. Changing the incident angle of the plane wave to the tag, due to the good symmetry of the tag, the shift of the RCS absorption extreme frequency point of the tag is small, which improves the feasibility of tag coding.

关键词： chipless tag angle insensitive frequency coding polarization coding

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