Ring-oscillator (RO)-based phase-locked loops (PLLs) are very attractive for system-on-chip applications for their compactness and tuning range, but suffer from high jitter and supply noise ...sensitivity. This paper presents a sub-sampling phase detector (SSPD)-based feedforward noise cancellation (FFNC) technique to improve these drawbacks of the RO PLL. The FFNC scheme utilizes the already available SSPD output to perform cancellation with high sensitivity while utilizing low power and area overhead. The 2- to 2.8-GHz RO PLL proof-of-principle prototype occupies 0.022 mm 2 active area in 65 nm CMOS; it achieves a 633 fs rms jitter at 2.36 GHz with 5.86 mW power consumption and an figure of merit (FOM jitter ) of -236.3 dB. The cancellation reduces the jitter by 1.4×, the phase noise by 10.2 dB to -123.5 dBc/Hz at 300-kHz offset, and the RO supply sensitivity by 19.5 dB for a 1 mVpp 100-kHz noise tone on the RO supply.
We propose a novel seismic noise attenuation approach based on least-squares Gaussian beam transform (LSGBT). Gaussian beam transform uses time-domain Gaussian beam (TGB), which can be characterized ...by a particular location, arrival time, amplitude, slope, curvature, and width. We implement the local attributes such as beam center, spacing, and width to perform Gaussian beam decomposition. In this approach, we first introduce the plane-wave decomposition (PWD) theory to implement TGB decomposition of noisy seismic data and then apply data reconstruction. Unlike most state-of-the-art algorithms, random noise is attenuated in the process of Gaussian beam reconstruction. In the reconstruction records, the useful events are well preserved simultaneously removing random noise. Comparisons of experimental results on field data using traditional <inline-formula> <tex-math notation="LaTeX">f </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">x </tex-math></inline-formula> deconvolution (FX Decon) and median filter (MF) methods are also provided, which suggest that our method achieves better denoising performance than FX Decon and MF methods. Taking into account that signal loss is sometimes unavoidable in almost all existing denoising methods. In addition to the signal-to-noise ratio (SNR) measurement, we also use local similarity as an efficient tool to evaluate denoising performance. A group of synthetic and field examples demonstrates the effectiveness of the proposed approach.
Environmental noise remains a complex and fragmented interplay between industrialization, population growth, technological developments, and the living environment. Next to the circulatory diseases ...and cancer, noise pollution has been cited as the third epidemic cause of psychological and physiological disorders internationally. A reliable and firm relationship between the cumulative health implications with the traffic annoyance and occupational noise has been established. This agenda has called for an integrated, coordinated, and participatory approach to the reliable protection of noise interference. Despite several fragmented policies, legislation and global efforts have been addressed; the noise pollution complaints have been traditionally neglected in developing countries, especially in Malaysia. This paper was undertaken to postulate an initial platform to address the dynamic pressures, gigantic challenges, and tremendous impacts of noise pollution scenario in Malaysia. The emphasis is speculated on the traffic interference and assessment of industrial and occupational noise. The fundamental importance of noise monitoring and modeling is proposed. Additionally, the confronting conservation program and control measure for noise pollution control are laconically elucidated.
•Block coordinate descent notably reduces complexity without degrading performance.•Momentum integration into block coordinate descent greatly improves convergence rate.•Block coordinate descent ...attains similar noise reduction to McFXLMS in real-time.
Multichannel active noise control (MCANC) is widely regarded as an effective solution to achieve a significantly large noise-cancellation area in a complicated acoustic field. However, the computational complexity of MCANC algorithms, such as the multichannel filter-x least mean square (McFxLMS) algorithm, grows exponentially with an increased channel count. Many modified algorithms have been proposed to alleviate the complexity but at the expense of noise reduction performance. Till now, the trade-off between computational complexity and noise reduction performance has limited the practical implementation of MCANC. The block coordinate descent McFxLMS (BCD McFxLMS) algorithm proposed in this paper substantially reduces the computation cost of an MCANC system, while maintaining the same noise reduction performance as the conventional McFxLMS algorithm. Furthermore, a momentum mechanism is integrated into the BCD McFxLMS in practice to improve the convergence speed. The simulation and experimental results validate the effectiveness of proposed algorithms when dealing with noise in a realistic environment.
Abstract
Passive acoustic monitoring (PAM) can be a powerful tool to survey populations of soniferous species in natural settings. Using PAM allows monitoring of behaviour and activity unobtrusively ...to get a more accurate assessment of behavioural responses than traditional techniques. The use of PAM can also be beneficial for behaviourally cryptic species or other taxa that might be missed by more traditional sampling methods.
To quantify seasonality of reproduction in an aquatic invasive species and to assess possible interactions between both abiotic and biotic noise and acoustic ecology, we deployed multiple hydrophones to fully characterise the acoustic behaviour of round goby (
Neogobius melanostomus
), a highly invasive species. We also aimed to quantify levels of anthropogenic noise around the goby communities. We tested correlations of round goby calling rates with overall noise levels and the presence of boat traffic as direct tests of the hypothesised role of noise on natural acoustic behaviour of fish.
Round goby showed a clear diel patterning of calling behaviour, with the highest activity during the night and ceasing at midday; supporting the importance of acoustic—as opposed to visual—signalling for mate attraction. Calls also allowed us to pinpoint spawning areas for possible remediation. We saw no correlation between measures of background noise and calling behaviour or presence of boats and calling, suggesting that increased levels of noise have no effect on the natural calling behaviour of this species.
Passive acoustic monitoring of round goby calling behaviour is a promising technique for those interested in remediation of this highly invasive species, as it can be difficult to quantify population levels by more conventional means. The lack of noise effects we see suggests that noise from recreational boats does not disrupt signalling in this species with limited hearing range, although more investigation is needed to ascertain whether noise could be a stressor in other contexts.
•Discrepancies between standard corrections and experimental results have been shown.•Detailed studies regarding the standard and its Annex B (informative) are necessary.•The measurement stand allows ...to perform research on any high building facades.
The article presents capabilities and application ranges of a newly designed portable device (a test stand) for a measurement of sound waves reflected from a building’s facade. What is more, the developed device can be also used to monitor the environmental noise. A detailed description of construction and assembly of the test stand was included. In many countries, ISO 1996-2 standard is a guideline on how to measure and assess acoustic environment. In this study, we made reference to the −3 and −5.7 dB corrections recommended in ISO 1996-2, depending on the location of the microphone at the facade of the building. Significant discrepancies between standard norm corrections and experimental results were indicated. In measurement conditions on the facade of a tall building, the research usefulness and ease of use of the constructed portable test stand was demonstrated. Thanks to the simplicity of the construction and the applied meter, the measurement stand allows to perform advanced research on any high building facades.
We propose a new robust recursive fixed-interval smoother for nonlinear systems under non-Gaussian process and measurement noises, i.e., the nominal Gaussian noise is polluted by large noise from ...unknown distributions. Taking advantage of correntropy in handling non-Gaussian noise, a robust Rauch-Tung-Striebel smoother is derived according to the maximum-correntropy-criterion-based cost functions with nonlinear functions linearized by their first-order Taylor series expansions, where two weights are utilized to adjust the estimation gains of forward filtering and backward smoothing, respectively. Simulation results demonstrate the effectiveness of the proposed smoother in the presence of various non-Gaussian process and measurement noises, especially the shot sequences and multimodal noise.
Multiplicative noise (also known as speckle noise) models are central to the study of coherent imaging systems, such as synthetic aperture radar and sonar, and ultrasound and laser imaging. These ...models introduce two additional layers of difficulties with respect to the standard Gaussian additive noise scenario: (1) the noise is multiplied by (rather than added to) the original image; (2) the noise is not Gaussian, with Rayleigh and Gamma being commonly used densities. These two features of multiplicative noise models preclude the direct application of most state-of-the-art algorithms, which are designed for solving unconstrained optimization problems where the objective has two terms: a quadratic data term (log-likelihood), reflecting the additive and Gaussian nature of the noise, plus a convex (possibly nonsmooth) regularizer (e.g., a total variation or wavelet-based regularizer/prior). In this paper, we address these difficulties by: (1) converting the multiplicative model into an additive one by taking logarithms, as proposed by some other authors; (2) using variable splitting to obtain an equivalent constrained problem; and (3) dealing with this optimization problem using the augmented Lagrangian framework. A set of experiments shows that the proposed method, which we name MIDAL (multiplicative image denoising by augmented Lagrangian), yields state-of-the-art results both in terms of speed and denoising performance.
Photovoltaic noise barriers (PVNBs) have the potential to contribute to sustainable urban development by increasing the supply of renewable energy to cities while decreasing traffic noise pollution. ...However, estimating the power generation of PVNBs at the city or national scale remains a challenge due to the complexities of the urban environment and the difficulties associated with collecting data on road noise barriers (RNBs) and radiation. This study used RNBs, 2.5-dimensional (2.5D) buildings, and hourly time resolution radiation data, to estimate the power generation of PVNBs in 52 of China's major cities. First, hourly building shadows were estimated for each day of the year, covering the period from sunrise to sunset, to identify areas of RNB that are shaded at any given time. Second, hourly clear-sky radiation data were collected and corrected using a radiation correction model to simulate real weather radiation. Finally, utilizing an inclined surface radiation estimation model, the photovoltaic (PV) potential both inside and outside RNBs affected by building shadows was assessed. Subsequently, the power generation of PVNB was estimated based on parameters of mainstream PV systems in the market. The results show that the RNB mileage in 52 selected cities represents 87.7% of China's total RNB mileage. Building shadows often result in a radiation loss of approximately 30% for RNBs reception. The installed capacity and annual power generation of PVNBs in all investigated cities are 2.04 GW and 690.74 GWh, respectively. This study estimates the comprehensive PV potential of potentially exploitable PVNBs in China, offering essential scientific insights to inform and facilitate the strategic development of PVNB projects at both the national and municipal levels.
•A framework to assess the photovoltaic (PV) potential of noise barriers is developed.•Building shadows are considered when assessing the PV potential of photovoltaic noise barriers (PVNB).•The RNB mileage of each city is closely and positively related to the PV potential on RNBs.•The annual power generation of PVNBs in China's 52 cities was estimated.
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