Emulating the Statistical Properties of Indoor Power Line Colored Background Noise for Development of a Power Line Noise Simulator

This paper deals with the development of a realistic power line channel simulator wherein power line communication devices can be tested before implementation to meet the massive need of data transfer. The statistics of the noise follow the experimentally observed in different sites, namely the time-varying non-white power spectral densities (PSDs) of the background noise and a target non Gaussian amplitude distribution. The procedure based on the inverse cumulative distribution function method of generation of random numbers and iteratively updating a target spectrum necessitates knowledge of a maximum of 17 parameters for successful implementation and has been validated for three sites in the low-frequency ([Formula: see text]500[Formula: see text]kHz) and high-frequency (1–30[Formula: see text]MHz) bands. The average percentage errors in prediction of the mean of the channel capacity (CC) are 12.68% and 10.66% in the two bands, respectively. The minimum correlations of the distribution of BER of OFDM in a channel corrupted by the simulated and observed noises are is 0.883 and 0.801 in the two bands which are high compared to 0.422 and 0.355, respectively, when the requirement of a target amplitude distribution is neglected. With low-frequency noise emulated by a data acquisition card, an average percentage error of 11.82% in the CC and a correlation of 0.867 (against 0.498) in BER are obtained. The noise thus generated can be used as a testbed for system testing, instead of the conventional static models (additive white Gaussian noise or with time-invariant colored PSD), leading to better optimization of the implemented devices.

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Single JFET Front-End Amplifier for Low Frequency Noise Measurements with Cross Correlation-Based Gain Calibration

Electronics ◽

10.3390/electronics8101197 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1197

Author(s):

Graziella Scandurra ◽

Gino Giusi ◽

Carmine Ciofi

Keyword(s):

Background Noise ◽

Cross Correlation ◽

Low Frequency ◽

Open Loop ◽

Low Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Front End ◽

Voltage Amplifier ◽

Noise Measurements

We propose an open loop voltage amplifier topology based on a single JFET front-end for the realization of very low noise voltage amplifiers to be used in the field of low frequency noise measurements. With respect to amplifiers based on differential input stages, a single transistor stage has, among others, the advantage of a lower background noise. Unfortunately, an open loop approach, while simplifying the realization, has the disadvantage that because of the dispersions in the characteristics of the active device, it cannot ensure that a well-defined gain be obtained by design. To address this issue, we propose to add two simple operational amplifier-based auxiliary amplifiers with known gain as part of the measurement chain and employ cross correlation for the calibration of the gain of the main amplifier. With proper data elaboration, gain calibration and actual measurements can be carried out at the same time. By using the approach we propose, we have been able to design a low noise amplifier relying on a simplified hardware and with background noise as low as 6 nV/√Hz at 200 mHz, 1.7 nV/√Hz at 1 Hz, 0.7 nV/√Hz at 10 Hz, and less than 0.6 nV/√Hz at frequencies above 100 Hz.

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Ambient noise from ocean surf drives frequency shifts in non-passerine bird song

10.1101/2020.06.17.156232 ◽

2020 ◽

Author(s):

Matteo Sebastianelli ◽

Daniel T. Blumstein ◽

Alexander N. G. Kirschel

Keyword(s):

Background Noise ◽

Ambient Noise ◽

Selective Pressure ◽

Low Frequency ◽

Vocal Learning ◽

Passerine Bird ◽

Anthropogenic Noise ◽

Masking Effect ◽

Frequency Noise ◽

Natural Noise

AbstractEffective communication in birds is often hampered by background noise, with many recent studies focusing on the effect of anthropogenic noise on passerine bird song. Continuous low-frequency natural noise is predicted to drive changes in both frequency and temporal patterning of bird vocalizations, but the extent to which these effects may also affect birds that lack vocal learning is not yet fully understood. Here we use a gradient of exposure to natural low-frequency noise to assess whether it exerts selective pressure on vocalizations in a species whose songs are innate. We tested whether three species of Pogoniulus tinkerbirds adapt their song when exposed to a source of continuous low-frequency noise from ocean surf. We show that dominant frequency increases the closer birds are to the coast in all the three species, and in line with higher noise levels, indicating that ocean surf sound may apply a selective pressure on tinkerbird songs. As a consequence, tinkerbirds adapt their songs with an increase in frequency to avoid the masking effect due to overlapping frequencies with ambient noise, therefore improving long-range communication with intended receivers. Our study provides for the first time, compelling evidence that natural ambient noise affects vocalizations in birds whose songs are developed innately. We believe that our results can also be extrapolated in the context of anthropogenic noise pollution, hence providing a baseline for the study of the effects of low-frequency ambient noise on birds that lack vocal learning.Significance StatementBirdsong is constantly under selection as it mediates key interactions such as mate attraction, competition with same-sex individuals for reproduction and competition with heterospecifics for space-related resources. Any phenomenon that interferes with communication can therefore have a profound impact on individual fitness. Passerines are more likely to avoid the masking effect of background noise because of their higher vocal flexibility. Many non-passerine species lacking such flexibility might therefore be more vulnerable to the negative effects on their fitness of exposure to low-frequency background noise. Species incapable of adapting their signals to background noise are predicted to disappear from noisy areas. Despite this, we show that species that lack song learning may show an adaptive response to natural noise which may develop over evolutionary timescales.

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Spatiotemporal patterns of avian vocal activity in relation to urban and rural background noise

Journal of Ecoacoustics ◽

10.22261/jea.z9tqhu ◽

2017 ◽

Vol 1 (1) ◽

pp. 1-1 ◽

Cited By ~ 4

Author(s):

Katherine E. Gentry ◽

David A. Luther

Keyword(s):

Background Noise ◽

Activity Patterns ◽

Low Frequency ◽

Rural Landscape ◽

Signal Interference ◽

Frequency Noise ◽

Low Frequency Noise ◽

Noise Levels ◽

Frequency Bands ◽

Vocal Activity

Background noise can interfere with and influence acoustic communication behavior. Signal interference is dependent on the amplitude and spectral characteristic of background noise, which varies over space and time. The likelihood of signal interference is greater when background noise is concentrated within the same frequency bands of an animal’s vocalization, but even a partial masking effect can elicit signaling behavior modification. Relative to a rural landscape, background noise in an urban landscape is disproportionately comprised by anthro- pogenic sound, which fluctuates in amplitude throughout the day and occurs primarily in low frequencies (0–2 kHz). In this study, we examined if urban-rural differences in vocal activity patterns exist in a species Zonotrichia leucophrys nuttalli that communicates above the frequency range of anthropogenic noise (2–8 kHz). We tested whether vocal activity patterns changed in relation to sound in the high or low frequency bands within and between urban and rural locations. Automated acoustic recording devices (ARDs) continuously recorded throughout the morning song chorus, 0500 to 1,100 h, during the 2014 breeding season in San Francisco (urban) and Marin (rural) Counties, CA. Supervised learning cluster analysis was used to quantify vocal activity by totaling the number of songs. In general, vocal activity was greater in urban locations com- pared to rural locations. However, within rural and urban study sites, we found vocal activity decreased where low frequency noise levels were higher. There was not a relationship between vocal activity and high frequency, biotic sound. In both urban and rural locations, low frequency noise levels increased through the morning, while vocal activity remained relatively consistent. Our results demonstrate how patterns of vocal activity can change with low frequency, abiotic noise, even when there is no direct spectral overlap with the acoustic signal.

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Baseline Correction of Digital Accelerograms from Field Testing of a Seismically Isolated Building

Earthquake Spectra ◽

10.1193/022817eqs040m ◽

2018 ◽

Vol 34 (2) ◽

pp. 915-939 ◽

Cited By ~ 5

Author(s):

Anastasia Athanasiou ◽

Giuseppe Oliveto ◽

Felice Ponzo

Keyword(s):

Background Noise ◽

Low Frequency ◽

Field Testing ◽

Computational Effort ◽

Frequency Noise ◽

Processing Scheme ◽

End Conditions ◽

Concrete Building ◽

Sudden Release ◽

Baseline Fitting

A three-story reinforced-concrete building in Augusta, Sicily, isolated at the base and designed according to the provisions of the latest Italian seismic regulations, was subjected to a series of push and sudden release tests in March 2013. During the tests, the displacements at the isolation level were measured along with the accelerations at each floor. The obtained records were then treated for the removal of low-frequency noise using a simple baseline-fitting scheme. The developed signal-processing scheme consists of defining the duration of the main event, removing the background noise, and using polynomial curves for the adjustment of the distorted baseline. The method does not require significant computational effort and accounts for initial and end conditions provided that these are known. Implementation of the method provides the adjusted response in terms of absolute and relative floor accelerations, velocities, and displacements, as well as interstory drifts.

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DEDICATED INSTRUMENTATION FOR HIGH SENSITIVITY, LOW FREQUENCY NOISE MEASUREMENT SYSTEMS

Fluctuation and Noise Letters ◽

10.1142/s0219477504001963 ◽

2004 ◽

Vol 04 (02) ◽

pp. L385-L402 ◽

Cited By ~ 23

Author(s):

C. CIOFI ◽

G. GIUSI ◽

G. SCANDURRA ◽

B. NERI

Keyword(s):

Background Noise ◽

Flicker Noise ◽

Low Frequency ◽

High Sensitivity ◽

Design Guidelines ◽

Low Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Low Frequencies ◽

Noise Measurements

Low Frequency Noise Measurements (LFNM) can be used as very sensitive tool for the characterization of the quality and the reliability of electron devices. However, especially in those cases in which the frequency range of interest extends below 1 Hz, instrumentation with an acceptable low level of background noise is not easily found on the market. In fact, at very low frequencies, the flicker noise introduced by the electronic components which make up the instrumentation becomes predominant and several interesting phenomena which could be detected by means of LFNM may result completely hidden in the background noise. This consideration is not limited to the case of input preamplifiers but does extend to any piece of instrumentation that contributes to the LFNM systems, and in particular to the power supplies used for biasing the Device Under Test. During the last few years, our research groups have been strongly involved in the design of very low noise instrumentation for application in the field of LFNM. In this work we report the main results which we have obtained together with a discussion of the design guidelines that have allowed us, in a few cases, to reach noise levels not to be equalled by any instrumentation available on the market.

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Spectral Characteristics of Heart Rate Variability in Noise Exposure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1079-1080.515 ◽

2014 ◽

Vol 1079-1080 ◽

pp. 515-521

Author(s):

Li Ho Tseng ◽

Ching Chang Yang ◽

Yuan Po Lee ◽

Hong Zhun Wu ◽

Chia Yi Chou

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Spectral Analysis ◽

Background Noise ◽

Low Frequency ◽

Cardiovascular Responses ◽

Frequency Noise ◽

Cardiovascular Activity ◽

Low Frequency Noise ◽

Noise Levels

Ecological studies have shown that the chronic effects of exposure to environmental noise cause annoyance. However, in the past, most studies have used questionnaires to evaluate the effects of noise pollution on psychosomatic responses. This study investigated cardiovascular activity changes in exposure to low-frequency noise at various noise intensities. The authors hypothesized that distinct noise intensities affect cardiovascular activity, which would be reflected in the spectral analysis parameters. The evaluation intensities of low frequency noises (from 20 to 200 Hz) were background noise (BN), 70-dBC, 80-dBC, and 90-dBC. The electrocardiographic (ECG) data was recorded for 5 minutes under various noise levels. The cardiovascular responses were evaluated using spectral analysis of the beat-to-beat (RR) intervals obtained from ECG signals. The results showed that the average blood pressure and mean RR interval variability did not substantially change relative to the noise levels. However, the low-frequency (LF) power and the ratio of LF power to high-frequency power (LF/HF) from ECG under the BN condition were significantly lower than the 80-dBC, and 90-dBC noise levels. In addition, the normalized LF of the background noise condition was significantly lower than the low-frequency of the noise levels at various intensities. In conclusion, the frequency-domain-based measures appear to be a powerful tool for exposure to low-frequency noise, even in short-term heart rate variability time series.

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HEMTs for low-power and low-frequency noise 4.2 K cryoelectronics : fabrication and characterization

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:1998330 ◽

1998 ◽

Vol 08 (PR3) ◽

pp. Pr3-131-Pr3-134 ◽

Cited By ~ 4

Author(s):

Y. Jin

Keyword(s):

Low Power ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Fabrication And Characterization

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Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.4.2020.08.0582 ◽

2020 ◽

Vol 14 (4) ◽

pp. 7396-7404

Author(s):

Abdul Malek Abdul Wahab ◽

Emiliano Rustighi ◽

Zainudin A.

Keyword(s):

Theoretical Model ◽

Resonance Frequency ◽

Dynamic Testing ◽

Experimental Results ◽

Percentage Error ◽

Initial Tension ◽

Average Percentage ◽

Soft Actuator ◽

Average Percentage Error ◽

Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

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