Showing papers on "Bandwidth expansion published in 2019"
TL;DR: In this article, a pole-zero temperature compensation proportional controller (PZTCPC) is proposed to expand the bandwidth of a dual-mass microelectromechanical system (MEMS) gyroscope under different temperatures.
Abstract: This paper presents a bandwidth expansion method for dual-mass microelectromechanical system (MEMS) gyroscopes based on the pole–zero temperature compensation method. When the sense loop operates under open conditions, the mechanical sensitivity of the gyroscope structure conflicts with the bandwidth and is governed by the frequency difference between the drive and the sense modes (min {Δ ω 1, Δ ω 2}), which is proven to change with temperature during the experiment. The pole–zero temperature compensation proportional controller (PZTCPC) is proposed to expand the bandwidth under different temperatures based on the pole–zero compensation method. The force rebalancing combs stimulation method (FRCSM) is used to achieve accurate gyroscope bandwidth characteristics. The mechanical bandwidth of the gyroscope is proven to be approximately 13 Hz when the sense-mode loop is open, and the simulation results show that the PZTCPC method expands the bandwidth to greater than 91.7 Hz after the sense-mode loop is closed. The FRCSM experiments indicate that gyroscope bandwidth is expanded to 95 Hz at –40 °C, 94 Hz at 20 °C and 92 Hz at 60 °C, while the bandwidths at –40, 20, and 60 °C are all 93 Hz with the turntable method. The experimental curves match the simulation curves well and verify the simulation results. The new limiting condition of the closed-loop bandwidth is the trough generated by conjugate zeros, formed by superposition of in-phase and anti-phase sense modes.
84 citations
12 May 2019
TL;DR: This work pairs a new 3-way split variant of the FFTNet neural vocoder structure with a perceptual loss function, combining objectives from both the time and frequency domains, and shows that it outperforms baseline methods from both domains, even for extreme bandwidth expansion.
Abstract: We introduce a perceptually motivated approach to bandwidth expansion for speech. Our method pairs a new 3-way split variant of the FFTNet neural vocoder structure with a perceptual loss function, combining objectives from both the time and frequency domains. Mean opinion score tests show that it outperforms baseline methods from both domains, even for extreme bandwidth expansion.
17 citations
TL;DR: A general framework that establishes a unified model for diversified speech data with different sampling rates and channels is proposed and the proposed methods are verified to be robust on different realistic scenes and can be effectively extended to a long short-term memory framework.
Abstract: Automatic speech recognition (ASR) systems are often built using scene related speech data due to large variations of transmission channels and sampling rates in different scenarios. In this study, we propose a general framework that establishes a unified model for diversified speech data with different sampling rates and channels. The framework is a joint optimization of deep neural network (DNN)-based bandwidth expansion and acoustic modeling to exploit a large amount of diversified training data. First, we design two novel DNN architectures to map the acoustic features from narrowband to wideband speech through direct mapping and progressive mapping. The learning targets of the direct mapping DNN (DNN-DM) are the acoustic features extracted from speech with the largest bandwidth, while the acoustic features from speech with all the other bandwidths are used as input. A progressive stacking network (PSN) gradually maps the features from the low sampling rates to the highest sampling rate through the design of intermediate target layers via multitask training. Then, in addition to these bandwidth expansion networks, we investigate several joint training strategies for DNN-based acoustic models. Our experiments conducted on three diversified large-scale Mandarin speech datasets with different recording channels and sampling rates (6, 8, and 16 kHz) show that the proposed unified model using PSN for bandwidth expansion not only is a more flexible and compact design than conventional multiple acoustic models with each bandwidth for a specific sampling rate, but also yields consistent and significant improvements over bandwidth-dependent models with an average relative word error rate reduction of 6.2%, indicating that the proposed model can fully utilize the diversified cross-channel speech data with multiple bandwidths. Moreover, the proposed methods are verified to be robust on different realistic scenes and can be effectively extended to a long short-term memory framework.
10 citations
TL;DR: In this article, a joint source channel coding (JSCC) problem is considered, where all the sources are partitioned into disjoint power-type classes, and an appropriate measure of the size of each power type class is taken into account in decoding strategy.
Abstract: We consider a joint source channel coding (JSCC) problem in which we desire to transmit an arbitrary memoryless source over an arbitrary additive channel. We propose a mismatched coding architecture that consists of Gaussian codebooks for both the source reproduction sequences and channel codewords. The natural nearest neighbor encoder and decoder, however, need to be judiciously modified to obtain the highest communication rates at finite blocklength. In particular, we consider an unequal error protection scheme in which all sources are partitioned into disjoint power-type classes. We also regularize the nearest neighbor decoder so that an appropriate measure of the size of each power type class is taken into account in the decoding strategy. For such an architecture, we derive ensemble-tight second-order and moderate deviations results. Our first-order (optimal bandwidth expansion ratio) result generalizes the seminal results by Lapidoth (1996 and 1997). The dispersion of our JSCC scheme is a linear combination of the mismatched dispersions for the channel coding saddle-point problem by Scarlett, Tan, and Durisi (2017) and the rate-distortion saddle-point problem by the present authors, thus also generalizing these results.
9 citations
01 Jul 2019
TL;DR: This work shows that for the problem of transmitting i.i.d uniform bits over a binary symmetric channels with Hamming distortion, the smallest attainable distortion is at least Ω(n−1/2) above the asymptotic value, if the "bandwidth expansion ratio" is above 1.
Abstract: We consider the classic joint source-channel coding problem of transmitting a memoryless source over a memoryless channel. The focus of this work is on the rate of convergence of the smallest attainable expected distortion to its asymptotic value, as a function of blocklength n. Our main result is that in general the convergence rate is not faster than n−1/2. In particular, we show that for the problem of transmitting i.i.d uniform bits over a binary symmetric channels with Hamming distortion, the smallest attainable distortion (bit error rate) is at least Ω(n−1/2) above the asymptotic value, if the "bandwidth expansion ratio" is above 1.
8 citations
27 Feb 2019
TL;DR: It is showed that the proposed method to expand the bandwidth from 10 MHz to 15 MHz can avoid congestion problem and impact on improving the performance of LTE network.
Abstract: QoS (Quality of Service) of LTE networks can bring the providers to provide broadband services with high performance to end user. Furthermore, the expected data rate transfer is up to 300 Mbit/s per user while the range of bandwidth varies from 1.4 MHz to 20 MHz. The network worked in 1800 MHz bands, 64 QAM modulation technique and used 10 MHz and 15 MHz channel bandwidth. There is a congestion problem for LTE network with 10 MHz channel bandwidth due to high utilization. The paper tries to analyze the QoS parameters, named Key Performance Indicators (KPI) for LTE Networks to solve the problem using bandwidth expansion. The KPIs parameter that is measured by drive test is accessibility, retainability, PRB downlink utilization, and user number. Based on the KPIs measurements results, it is showed that the proposed method to expand the bandwidth from 10 MHz to 15 MHz can avoid congestion problem and impact on improving the performance of LTE network.
7 citations
TL;DR: In this article, a linear polarization converter based on a square split ring metasurface is proposed, which can achieve ultra-broadband, high efficiency, wide-angle, and simple geometry simultaneously.
Abstract: Polarization state of electromagnetic wave has important applications in satellite communication, radar detection, and stereoscopic display imaging. Therefore, the control of polarization state of electromagnetic wave is an important direction in scientific research. The traditional method of manipulating the polarization state is mainly realized based on Faraday effect and birefringent crystal, which has a certain requirement for the material thickness (leading to large volume), and does not have broadband characteristics (leading to narrow band). Recently, metamaterial with subwavelength meta-atoms, has achieved many exotic phenomena and functionalities that cannot be found in nature. As an important branch of metamaterial-based devices, polarization converter has attracted great attention and achieved significant progress. However, most of them cannot realize ultra-broadband, high-efficiency, wide-angle, and simple geometry simultaneously. In this paper, a linear polarization converter based on a square split ring metasurface is proposed. Due to the anisotropic structure, the amplitudes of the reflected electric field along the two diagonal lines are equal, and their phase difference is 180°. As a result, the polarization direction of the incident wave can be rotated 90°. The simulation results show that the polarization conversion ratio (PCR) is higher than 90% in a frequency range from 7.12 to 18.82 GHz, which means that the relative bandwidth reaches 90%. The significant bandwidth expansion is attributed to the four electromagnetic resonances generated in a square-split-ring unit. We investigate the influence of geometric parameters on PCR in detail. We also examine the performance of the proposed structure under oblique incidence. It has little effect on the co-polarization and cross-polarization reflection coefficients when the incident angle is changed from 0° to 45°. Even if the incident angle reaches 45°, the mean PCR remains above 80%. The PCRs of the four electromagnetic resonant points are all close to 100%. Finally, we fabricate and measure the proposed polarization converter that contains \begin{document}$30\times30$\end{document} unit cells. The experimental results are in good agreement with the simulation results, and thus validating the design. In conclusion, we propose both theoretically and experimentally a linear polarization converter that possesses ultra-broadband, high-efficiency, wide-angle, and simple geometry simultaneously. The proposed scheme can be extended to terahertz and even optical frequencies.
7 citations
TL;DR: The generalized sensor fusion framework, named the closed-loop fusion (CLF), is analyzed, and the optimal design principle of filter is proposed in detail in order to improve measurement of the bandwidth of MEMs gyro by integrating information of MEMS accelerometers.
Abstract: Micro-electro-mechanical system (MEMS) gyro is one of the extensively used inertia sensors in the field of optical target tracking (OTT). However, velocity closed-loop bandwidth of the OTT system is limited due to the resonance and measurement range issues of MEMS gyro. In this paper, the generalized sensor fusion framework, named the closed-loop fusion (CLF), is analyzed, and the optimal design principle of filter is proposed in detail in order to improve measurement of the bandwidth of MEMS gyro by integrating information of MEMS accelerometers. The fusion error optimization problem, which is the core issue of fusion design, can be solved better through the feedback compensation law of CLF framework and fusion filter optimal design. Differently from conventional methods, the fusion filter of CLF can be simply and accurately designed, and the determination of superposition of fusion information can also be effectively avoided. To show the validity of the proposed method, both sensor fusion simulations and closed-loop experiments of optical target tracking system have yielded excellent results.
3 citations
16 May 2019
TL;DR: It is demonstrated that 14.2-nm bandwidth for −20-dB crosstalk in a strictly-non-blocking Si switch, corresponding to four-times expansion from conventional design, is demonstrated.
Abstract: We demonstrate 14.2-nm bandwidth for −20-dB crosstalk in a $32 \times 32$ strictly-non-blocking Si switch, corresponding to four-times expansion from conventional design. The cross-port extinction that exhibits inherently low wavelength dependency is exploited.
3 citations
01 Sep 2019
TL;DR: This paper explores a method to combine multiple simultaneous Software Defined Radio (SDR) collections to achieve instantaneous bandwidth expansion through both Matlab simulations and hardware testing.
Abstract: An increase in instantaneous bandwidth without the use of custom designed equipment is desirable for nearly every application involving a receiver. Current bandwidth expansion methods focus on custom designed solutions along with known transmitted signals to aid in the bandwidth expansion. These methods also focus on sub-band collections one after the other, which is useless with non-Wide Sense Stationary (WSS) applications that vary over time. This paper explores a method to combine multiple simultaneous Software Defined Radio (SDR) collections to achieve instantaneous bandwidth expansion through both Matlab simulations and hardware testing.
2 citations
Patent•
09 Apr 2019
TL;DR: In this paper, an audio frequency bandwidth expansion method based on GA optimized model parameters is proposed, where the root-mean-square energy of each sub-band is calculated so as to obtain a low frequency spectrum envelope sequence.
Abstract: The invention discloses an audio frequency bandwidth expansion method based on genetic algorithm optimized model parameters. The audio frequency bandwidth expansion method based on genetic algorithm optimized model parameters comprises following steps: 1, input audio frequency signal x(n) is subjected to pretreatment so as to obtain filtering signal; 2, the filtering signal is subjected to modulated lapped transform so as to obtain low frequency modulated lapped transform coefficient; 3, the low frequency modulated lapped transform coefficient is divided into sub-bands, the root-mean-square energy of each sub-band is calculated so as to obtain a low frequency spectrum envelope sequence; 4, based on the low frequency spectrum envelope sequence, gray model GM (1, 1) is adopted for estimationof high frequency sub-band energy of the audio frequency signal so as to obtain a high frequency spectrum envelope; 5, frequency spectrum coping, frequency spectrum folding, non-linear calculating, integration multi-band excitation or non-linear predicting method are adopted for audio frequency spectrum detail expansion so as to obtain high frequency spectrum details; 6 based on the high frequency spectrum envelope and high frequency spectrum details, recovery of high frequency spectrum information of the audio frequency signal x(n) is carried out; and 7, modulated lapped inverse transform isadopted to realize x(n) bandwidth expansion.
01 Aug 2019
TL;DR: In this paper, an ultra-wideband tightly coupled array antenna with low profile is proposed, which utilizes the mutual coupling between elements to expand the array bandwidth, solve the problem of coupling suppression, and achieves the bandwidth expansion.
Abstract: An ultra-wideband tightly coupled array antenna with low profile is proposed in this paper. The tightly coupled array utilize the mutual coupling between elements to expand the array bandwidth, solves the problem of coupling suppression, and achieves the bandwidth expansion. This paper uses dual-polarized dipole array to reduce the array size and increase the gain. At the same time, the resistance absorption layer (RFSS) is located between the antenna and the floor to change reflection of the floor, expand the bandwidth while greatly reducing the profile. The dual-polarized antenna bandwidth of the dipole array can achieve 2 ∼9.53 GHz ( $\text{VSWR} ), the bandwidth ratio is close to 5:1, and the profile is lower than $\lambda_{\text{max}}/15$ .
24 Apr 2019
TL;DR: This work shows that the bit-error rate (BER) of the OPPM scheme can be further improved using a priority decoding method, without additional expansion in bandwidth.
Abstract: Offset pulse position modulation (OPPM) the signal modulation scheme offers key advantages compared to other existing pulse position modulation (PPM) schemes, namely greater sensitivity and reduced bandwidth expansion. Most error correction schemes result in bandwidth reduction of the system. This work shows that the bit-error rate (BER) of the OPPM scheme can be further improved using a priority decoding method, without additional expansion in bandwidth. An experimental link incorporating visible light communication (VLC) system based on ‘cool’ 30 W LED was used. This study also addresses the difference of using cool and warm white LEDs for a VLC system. The experimental results show cool white LED achieves improved performance compared to previously studied warm white LED. The OPPM scheme, along with priority decoding, was implemented on FPGA, using VHDL. This study compares the BER results between original and improved OPPM, showing significant improvement in BER of priority decoding OPPM. The analysis has also been made on how the priority decoding operates and limitations of the system.
01 Nov 2019
TL;DR: In this paper, the authors proposed a novel approach of DNN-based statistical parametric speech synthesis where non-negative matrix factorization (NMF) is effectively utilized, which can potentially incorporate some applications of NMF, such as bandwidth expansion, voice conversion, or noise reduction.
Abstract: This paper proposes a novel approach of DNN-based statistical parametric speech synthesis where non-negative matrix factorization (NMF) is effectively utilized. In statistical parametric speech synthesis, Mel-frequency cepstrum is often employed for acoustic features. However, it represents a spectral envelope as a linear combination of fixed envelope curves (sines and cosines), and the envelope predicted by a DNN-based acoustic model loses its fine structure. On the other hand, in NMF, multiple spectral envelopes (spectrogram) are decomposed into two factors; spectral bases and their activity patterns (activation). Since the obtained bases keep the fine structure of envelopes, the remaining factor, i.e. activation can be employed for acoustic features. Due to its sparseness, the spectral envelope obtained by the predicted activation also keeps fine structure. In this study, activation derived from NMF is utilized for spectral representation, and DNN-based text-to-speech synthesis incorporating NMF is proposed. In addition, this framework can potentially incorporate some applications of NMF, such as bandwidth expansion, voice conversion, or noise reduction. In this study, bandwidth expansion is achieved, and experimental results demonstrate that the proposed method can generate more natural spectral parameters especially in 48 kHz sampling rate, and that 16 kHz-to-48 kHz bandwidth expansion, where natural synthetic speech is produced, is achieved in the proposed framework.
TL;DR: The problem of transmitting a Gaussian source over a slow-fading channel, when the aim is to adjust system parameters so that the source is reconstructed with minimum expected distortion is considered.
Abstract: In this paper, we consider the problem of transmitting a Gaussian source over a slow-fading channel, when the aim is to adjust system parameters so that the source is reconstructed with minimum expected distortion. In the considered scenario, the spatial distribution of users is modelled by a homogeneous Poisson point process. These users transmit their symbols by means of multicarrier frequency hopping modulation in which the frequency diversity characteristic is implemented by dividing the available bandwidth into several subbands where each subband consists of several subchannels. The number of subbands has a significant effect on the improvement of the system’s performance. We can have as many descriptions as the number of available subbands. In this way, we consider a combination of symmetric multiple description coding as the source coding and direct channel transmission coding as the channel coding so as to code the source signal into several descriptions which have the same number as the subbands. Considering separate source-channel coding strategy, we compute the expected distortion and evaluate the effects of system parameters on it. Furthermore, with the goal of minimizing the expected distortion, the optimum values of some system parameters in general and also for the case where the bandwidth expansion ratio is equal to one, are calculated. Through the optimization process, the optimum number of subbands and the optimum value of source coding rate are determined which lead to a significant improvement in the network performance.
Patent•
13 Jun 2019
TL;DR: In this article, a mobile terminal for bandwidth expansion of an LET B42 band and an implementation method thereof, the terminal comprising: a radio frequency circuit combining LTE downlink three-carrier aggregation technology for the 1.7-2.7 GHz band, a 4×4 multimode multiband antenna design, and 256-QAM coding technology; and a B42 transmit path and a receive path provided on the radio frequency circuits.
Abstract: A mobile terminal for bandwidth expansion of an LET B42 band and an implementation method thereof, the terminal comprising: a radio frequency circuit combining LTE downlink three-carrier aggregation technology for the 1.7-2.7 GHz band, a 4×4 multimode multiband antenna design, and 256-QAM coding technology; and a B42 transmit path and a receive path provided on the radio frequency circuit. The B42 transmit path comprises a B42 radio frequency power amplifier and a B42 power coupler connected to a transmit end of a main antenna on the radio frequency circuit. The receive path comprises a B42 transceiver filter and a frequency divider connected onto four antennas of the radio frequency circuit.
TL;DR: This work considers the broadcasting of a scalar memoryless Gaussian source over a two-user Gaussian broadcast channel with bandwidth expansion and derives a necessary condition for the achievability of a mean-squared-error distortion pair at the two receivers, which extends the Reznic–Feder–Zamir bound.
Abstract: We consider the broadcasting of a scalar memoryless Gaussian source over a two-user Gaussian broadcast channel with bandwidth expansion. In concurrent with the source description, a message that should be decoded reliably just by the “higher quality” user is sent. Conditioned on the message rate, we derive a necessary condition for the achievability of a mean-squared-error distortion pair at the two receivers, which extends the Reznic–Feder–Zamir bound. This necessary condition and a sufficient condition that we derive establish the set of achievable energy-distortion exponents for this setting.
Patent•
03 Dec 2019
TL;DR: In this paper, an implementation method of a spatial information network large-scale link simulator is described, which consists of a basic link simulator, an SDN controller and a switch, where the controller comprises a bandwidth allocation module and the switch comprises a link expansion module.
Abstract: The invention discloses an implementation method of a spatial information network large-scale link simulator. The system comprises a basic link simulator, an SDN controller and an SDN switch, whereinthe SDN controller comprises a bandwidth allocation module, the basic link simulator comprises a link simulation module and a bandwidth expansion module, and the link simulation module is used for realizing the most basic function of simulating link characteristics and simultaneously realizing accurate simulation of a plurality of spatial links so as to meet the basic requirements of simulation ofa plurality of links among spatial information network nodes; the bandwidth extension module effectively breaks through the bandwidth upper limit of a single link originally simulated by a link simulator through an SDN group table and a link aggregation technology; a bandwidth allocation algorithm is integrated in the bandwidth allocation module, the number of links supported by the link simulator is effectively increased through the algorithm, and the link simulator has the advantages of being authentic, flexible, extensible and the like and can be well applied to a spatial information network.
Patent•
21 May 2019
TL;DR: In this article, a pre-stack seismic data spectrum expansion method based on angle division processing is proposed, in which the energy information of the high-frequency end and the lowfrequency end can be effectively predicted, the seismic signal bandwidth is expanded, signal resolution is obviously improved, and a high signal-to-noise ratio is kept.
Abstract: The invention discloses a pre-stack seismic data spectrum expansion method based on angle division processing. The method comprises the following steps: step 01, reading CRP gather data, and dividingthe data into a far angle, a middle angle and a near angle; step 02, setting corresponding ratio parameters at the CRP gather sub-angles in the step 01, and determining a reference frequency and a frequency expansion range for each gather of data in the sub-angles; step 03, performing continuous wavelet transform on each gather of data of the CRP gather sub-angles in the step 02, and converting the data from time domain to time-scale domain; and step 04, expanding the signal bandwidth in the time-scale domain, carrying out inverse transformation of continuous wavelet transformation, reconstructing a spread-spectrum high-resolution time signal, and obtaining CRP gather data after bandwidth expansion; repeating the steps 03 and 04 till finishing processing all gathers of data. By applying the method, the energy information of the high-frequency end and the low-frequency end can be effectively predicted, the seismic signal bandwidth is expanded, the signal resolution is obviously improved, and a high signal-to-noise ratio is kept.