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Showing papers on "Impulse noise published in 1992"


Proceedings ArticleDOI
13 Oct 1992
TL;DR: An adaptive impulse noise cancellation device is described, expected to substantially reduce the impact of impulse noise in asymmetrical digital subscriber lines (ADSLs) and will also benefit any digital transmission systems.
Abstract: An adaptive impulse noise cancellation device is described. It is expected to substantially reduce the impact of impulse noise in asymmetrical digital subscriber lines (ADSLs) and will also benefit any digital transmission systems. It is capable of cancelling any of several different impulse shapes on a given loop, and the shapes can be learned by the device after it is installed. The canceler uses a relatively simple neuromorphic network. >

37 citations


Patent
04 Jun 1992
TL;DR: In this paper, the authors present a noise eliminating circuit for a television receiver that outputs an image signal without any noise by detecting and eliminating impulse noise and effecting interpolation for an image.
Abstract: The noise eliminating circuit for a television receiver according to the present invention outputs an image signal without any noise by detecting and eliminating impulse noise and effecting interpolation for an image signal, in the case where C/N of a received signal is lowered and impulse noise is produced. The noise eliminating circuit stated above is a noise detecting circuit, which detects only the noise component and judges whether the C/N is such that impulse noise is produced or not, depending on the level of the detection output. In the case where it is judged that there exists an impulse noise, a noise reduction circuit detects an impulse noise portion in the image signal and a brightness signal and a chrominance signal of this portion are subjected to interpolation processing so that an image signal, from which the impulse noise component is removed.

15 citations


01 Feb 1992
TL;DR: In this paper, the frequency spectrum of an impulse is considered as a variable in the evaluation of the hazards to the auditory system, and a frequency weighting function is used to determine the relative potential that impulsive energy has in causing auditory system trauma.
Abstract: : The energy spectrum of a noise is known to be an important effects of a traumatic exposure. However, existing criteria for exposure to impulse noise do not consider the frequency spectrum of an impulse as a variable in the evaluation of the hazards to the auditory system. This report presents the results of three studies that were designed to determine the relative potential that impulsive energy has in causing auditory system trauma. Four hundred and seventy five (475) chinchilla were used in these experiments. Pre- and post- exposure hearing thresholds were measured on each subject. In the first study, the noise exposure stimuli consisted of six different computer-generated narrow band tone bursts having center frequencies located at 0.260, 0.775, 1.025, 1. 350, 2.450, and 3.550 kHz. Each narrow band exposure stimulus was presented at two to four different intensities. An analysis of the audiometric data allowed a frequency weighting function to be derived. This weighting function de- emphasizes low frequency energy more than the conventional A-weighting function. In the second study, the exposures consisted of two--types of broad band computer synthesized impulses. Subjects were exposed to 100 impulses at a rate of 1-per-3-seconds. Each type of impulse was presented at 3 intensities. The third study used impulses generated by three different diameter shock tubes. Subjects were exposed to 1, 10, or 100 impulses at one of three intensities. The results of the second and third studies were interpreted using the weighting' function derived from the first study. The hearing loss from all three studies is a linear function of the weighted SEL calculated using the weighting function, derived in the first study. Impulse noise, Hearing, Chinchilla, Audiometry and histology.

10 citations


Patent
Byong-Min Min1
02 Jun 1992
TL;DR: In this paper, the noise characteristic in which has no vertical correlation and of which frequency component has 2 MHz or more in a horizontal direction at least is used to reduce the impulse noise component.
Abstract: An image signal processing system such as a television, a video tape recorder, a video disk player, a digital camera and the like, more particularly to an impulse noise reduction method and circuit which can reduce impulse noise component effectively in the image signal without damage of the original input image signal by using the noise characteristic in which has no vertical correlation and of which frequency component has 2 MHz or more in a horizontal direction at least.

8 citations


Journal ArticleDOI
01 Mar 1992
TL;DR: A filter has been devised with the aim of removing impulses in shifting object boundaries while maintaining the remainder of the data unchanged, and tests confirm that, at least for isolated impulse noise spikes, this is achieved.
Abstract: This paper is concerned with the suppression of noise from one- or two-dimensional signals. Commonly, these will arise as acoustic waveforms or images from a variety of sources. The aim of this work is to ensure that the resulting signals are as distortion free as possible. Preceding work using the median filter has shown that it can result in edges being shifted by noise or (in two dimensions) as a result of the curvature of object boundaries. Here the concern is with the effect of impulses in shifting object boundaries. A filter has been devised with the aim of removing such impulses while maintaining the remainder of the data unchanged. Hence, later application of a median or other filter should produce no specific impulse-induced distortion. Tests confirm that, at least for isolated impulse noise spikes, this is achieved. The results are shown to be of particular value in image interpretation using Hough transforms.< >

7 citations


Journal ArticleDOI
TL;DR: In this article, the authors present the results of a study that was designed to determine the relative potential that impulsive energy concentrated at different frequencies has in causing auditory system trauma, where one hundred and thirty (130) chinchilla, divided into 22 groups with 5 to 7 animals per group, were used in these experiments.
Abstract: Existing criteria for safe exposure to impulse noise do not consider the frequency spectrum of an impulse as a variable in the evaluation of the hazards to the auditory system. This report presents the results of a study that was designed to determine the relative potential that impulsive energy concentrated at different frequencies has in causing auditory system trauma. One hundred and thirty (130) chinchilla, divided into 22 groups with 5 to 7 animals per group, were used in these experiments. Pre‐ and post‐exposure audiograms were measured on each animal using avoidance conditioning procedures. Quantitative histology (cochleograms) was used to determine the extent and pattern of the sensory cell damage. The noise exposure stimuli consisted of seven different computer‐generated narrow‐band impulses (approximately 400‐Hz bandwidth) having center frequencies located at 0.260, 0.775, 1.025, 1.350, 2.075, 2.450, and 3.550 kHz. Each narrow‐band exposure stimulus was presented at two to four different intensi...

5 citations


Patent
23 Dec 1992
TL;DR: In this paper, a noise defecting circuit was proposed for a television receiver to detect and eliminate impulse noise and effecting interpolation for an image signal, in the case where the carrier to noise ratio (C/N) of a received signal is lowered and impulse noise is detected.
Abstract: A noise eliminating circuit 6, 8 for a television receiver outputs an image signal 10 without noise by detecting and eliminating impulse noise and effecting interpolation for an image signal, in the case where the carrier to noise ratio (C/N) of a received signal is lowered and impulse noise is detected The noise eliminating circuit 6, 8 comprises a noise defecting circuit 8, which detects only the noise component and judges whether the C/N is such that impulse noise is likely to be produced or not When it is judged that there exists impulse noise, a noise reduction circuit 6 detects noise pulses in the image signal and a brightness signal and a chrominance signal of this portion are separately interpolated so that an image signal from which the impulse noise component is removed is produced If impulse noise is not likely to be produced, the noise reduction circuit is rendered inoperative In an alternative, image ratios may be taken into account (figs 14, 15)

4 citations


Patent
10 Feb 1992
TL;DR: In this article, an absolute value circuit was proposed to detect the presence of impulse noise in a high-pass filter and a comparator circuit to discriminate the level of the high-frequency component.
Abstract: PURPOSE:To easily detect impulse noise by providing an absolute value circuit to get the absolute value of a high frequency component extracted by a high- pass filter, and a comparator circuit to discriminate the level of the high frequency component, which is turned to the absolute value by this absolute value circuit, and to generate an impulse noise detection signal showing the presence of the impulse noise when this high frequency component is larger than a prescribed value. CONSTITUTION:A reference level generation circuit 10 generates a reference level voltage showing a reference level for deciding whether the impulse noise is included in an FM modulation signal or not, and supplies this voltage to the inverted input terminal of a comparator 14. A signal obtained by detecting the FM modulation signal in an FM detection circuit 11 is divided into a component to be modulated and the impulse noise component after executing a filtering processing in a high-pass filter 12, and the impulse noise component is turned to the signal of positive polarity by an absolute value circuit 13. The signal is compared with the reference level voltage by a comparator 14, and the presence/absence of the impulse noise is decided.

3 citations


ReportDOI
01 Jan 1992
TL;DR: The Committee on Hearing, Bioacoustics, and Biomechanics (CHABA) proposed a limit for exposure to impulse noise (gunfire) in which the response was a specific amount of temporary threshold shift (TTS) and dose was specified in terms of the peak pressure and two aspects of the duration of a particular impulse, with correction factors for number of impulses and for the angle of incidence on the ear.
Abstract: : Limits for exposure to hazardous agents are set by defining some specific acceptable effect (the response) and then determining what exposure conditions (the dose) produce that effect. In 1968, the Committee on Hearing, Bioacoustics, and Biomechanics (CHABA) proposed a limit for exposure to impulse noise (gunfire) in which the response was a specific amount of temporary threshold shift (TTS) and dose was specified in terms of the peak pressure and two aspects of the duration of a particular impulse, with correction factors for number of impulses and for the angle of incidence on the ear. The proposal was basically an endorsement of one advanced by an Anglo-American team of investigators (Coles, Garinther, Hodge, and Rice, 1968) that was based on the very limited pool of information then available about the auditory hazard of gunfire. Coles, Garinther, and Hodge were members of the Working Group on Proposed Damage-Risk Criterion for Impulse Noise (Gunfire).

3 citations


Book ChapterDOI
01 Jan 1992
TL;DR: In this paper, the authors discuss how noise and interference affects a signal, and how to reduce the effects of noise and interfere in a communications link. But the effects cannot be eliminated entirely, but by careful design and construction, they can be reduced to very acceptable levels.
Abstract: This chapter discusses how noise and interference affects a signal. Noise in the communications sense is any spurious signal that tends to corrupt a wanted one. It is, thus, a destroyer of information and can be the ultimate limiting factor in a communications link. Noise may be natural or artificial in origin. The former, which includes electromagnetic radiation from solar, galactic or thermal sources, is often described collectively as sky noise. The effects of noise cannot be eliminated entirely, but by careful design and construction, they can be reduced to very acceptable levels. Noise appears as random variation of signal voltages or currents, unrelated in phase or frequency. Such signals have a large peak-to-RMS ratio typically in the order of 4:1, so the annoyance factor is related to the noise power or its mean square voltage or current. Another type of noise that is usually described as interference is produced by other RF carriers present. In this case, the noise tends to be periodic and regular in form. Nevertheless, it creates a major problem. Even a transmitter generates noise. Its nonlinearities cause distortion, which in turn produces unwanted radiation of harmonics.

3 citations


Proceedings ArticleDOI
19 Oct 1992
TL;DR: This paper presents the measurement techniques, the results and a brief analysis of: instantaneous and average power; large scale fading characteristics; delay spread characteristics; temporal variance of the channel; analysis of noise samples;Analysis of the impact of impulse noise on barker sequence correlation peaks.
Abstract: The quest for a robust, reliable open standard for wireless communication which would support manufacturing applications, required a thorough understanding of the channel characteristics. At the time this work was undertaken (summer 1989), relatively little literature on factory environments existed. In addition the published tests recorded received power and did not measure the phase, but assumed that it was randomly distributed. The test at G.M. measured both amplitude and phase to provide the complete impulse response. Given this impulse response, it is possible to evaluate the performance of any type of bandwidth limited modulation in this channel. This paper presents the measurement techniques, the results and a brief analysis of: instantaneous and average power; large scale fading characteristics; delay spread characteristics; temporal variance of the channel; analysis of noise samples; analysis of the impact of impulse noise on barker sequence correlation peaks. >

Patent
29 Jun 1992
TL;DR: An impulse noise detector for detecting impulse noise in video signal includes a band pass filter for passing a band of video signal frequencies centered in the spectral region of video signals which exhibit a relative energy minimum as mentioned in this paper.
Abstract: An impulse noise detector for detecting impulse noise in video signal includes a band pass filter for passing a band of video signal frequencies centered in the spectral region of video signals which exhibit a relative energy minimum. The band pass filtered signal is applied to a vertical comb filter. A threshold detector is coupled to the output connection of the comb filter for detecting the occurrences of impulse noise.

01 May 1992
TL;DR: In this paper, the authors developed a mathematical model of the ear that reproduces the response of ear from free field pressures to basilar membrane displacements and calculates hazard there (modeled as mechanical stress), which can be used to calculate a hazard index for virtually any impulse.
Abstract: : Research indicates that traditional measures fail to rate hazard from intense impulses accurately. This failure may be due to increased complexities in the ear's response at such high sound pressure levels. Therefore, to gain insight into the problem, we have been developing a mathematical model of the ear that reproduces the response of the ear from free field pressures to basilar membrane displacements and calculates hazard there (modeled as mechanical stress). This model is conformal with the structure of the ear and includes the spectral tuning of the external and middle ears, a non-linear stapes, and a changing susceptibility along the cochlear partition. The model can be used to calculate a hazard index for virtually any impulse and although work is still continuing on the development of the model, it is thus far able to explain the hearing loss data better than any other system. If the model were incorporated into an integrated circuit/meter, it would have the virtues of being complex enough to rate hazard accurately, be simple to use, and because it is theoretically based, be useful in suggesting design changes for impulse- producing sources as well as more effective designs for hearing protectors. hazard rating, spectrum, impulse noise, impulse noise, noise hazard.

Patent
05 Oct 1992
TL;DR: In this article, a video signal, a signal obtained by delaying this video signal by a 1H delaying circuit and a signal generated by further delaying this signal by another 1H delay circuit are input to a noise detecting circuit through BEFs 26, 25 and 24, respectively, and they are inputted to a 3-line comb line filter 18 through BPFs 12, 13 and 14, respectively.
Abstract: PURPOSE:To eliminate the impulse noise generated in a video signal CONSTITUTION:A video signal, a signal obtained by delaying this video signal by a delaying circuit 10, and a signal obtained by further delaying this signal by a 1H delaying circuit 11 are inputted to a noise detecting circuit 27 through BEFs 26, 25 and 24, respectively Simultaneously, they are inputted to a 3-line comb line filter 18 as well through BPFs 12, 13 and 14, respectively The noise detecting circuit 27 executes an arithmetic processing based on three inputted signals, and outputs a control signal for discriminating whether an impulse noise exists or not The 3-line comb line filter 18 also executes an arithmetic processing based on three inputted signals, and outputs a chrominance signal In such a state, when the impulse noise is detected, an SW 17 is turned off In this case, an SW 23 selects a signal obtained by inverting the output of the 3-line comb line filter 18 as a chrominance signal Subsequently, an SW 22 selects a signal obtained by adding this chrominance signal and an output signal of a delay circuit 15 as a luminance signal

Patent
29 Sep 1992
TL;DR: In this paper, the average value of each of the measured values is computed by computing an average value excluding the maximum value of a measured value sampled in a specified cycle, and the measured data obtained in this way is not influenced by the impulse noise and its measuring error is small.
Abstract: PURPOSE:To carry out accurate measurement and data processing of analog data even in the case when an irregular impulse noise is superimposed by computing an average value excluding the maximum value of a measured value sampled in a specified cycle. CONSTITUTION:A processing device is constituted of a sampling means 1. to sample an input analog signal, a computing means 2 to gain an average value except for the maximum value of a sampled measured value and an impulse detection means 3 to detect an impulse noise contaminated in an input signal. When a corrugated analog signal B with an impulse noise C contaminated in it is input, it is sampled in a specified sampling cycle T, and an average value of each of the measured values is computed. At this time, the maximum value of the sampled measured value is excluded and the average value is computed, and this is processed as measured data. The measured data obtained in this way is not influenced by the impulse noise and its measuring error is small, and it comes to be possible to carry out accurate measurement and data processing.

Proceedings ArticleDOI
06 Dec 1992
TL;DR: It is shown that impulse noise can significantly affect the performance of QAM systems, such as the QAM-based ADSL, when they operate on local telephone loops.
Abstract: An analytical method for estimating the bit error probability performance of a quadrature amplitude modulation (QAM) transmission system in the presence of impulse noise is presented. Numerical results are demonstrated, using parameters that are typical of the recently proposed asymmetrical digital subscriber lines (ADSLs) for digital transmission over the local copper telephone loop plant. It is shown that impulse noise can significantly affect the performance of QAM systems, such as the QAM-based ADSL, when they operate on local telephone loops. >

Patent
10 Feb 1992
TL;DR: In this article, a deemphasis circuit was proposed to remove impulse noise without degrading picture quality by providing a de-emphasis circuit to de-emphasize a signal interpolated by an interpolation circuit as needed, and a lowpass filter circuit to generate a demodulated signal by executing a low-pass filtering processing to the deemphasized signal.
Abstract: PURPOSE:To remove impulse noise without degrading picture quality by providing a de-emphasis circuit to de-emphasize a signal interpolated by an interpolation circuit as needed, and a lowpass filter circuit to generate a demodulated signal by executing a low-pass filtering processing to the de-emphasized signal. CONSTITUTION:When an impulse noise detection signal is not supplied from an impulse noise detection circuit 2, an interpolation circuit 3 fetches a signal to be supplied from an FM detection circuit 1 and supplies this signal to a de-emphasis circuit 4 as it is. When the impulse noise detection signal is supplied from the impulse noise detection circuit 2, the interpolation circuit 3 fetches a signal to be supplied from the FM detection circuit 1 and supplies this signal to the de-emphasis circuit 4 after interpolating the above-mentioned signal by a normal signal before or after one horizontal period or the like. The de- emphasis circuit 4 de-emphasizes the signal to be supplied form the interpolation circuit 3, returns a pre-emphasized part to be original and supplies this to a low-pass filter circuit 5.

Patent
03 Feb 1992
TL;DR: In this paper, a median filter 10 is used for a picture element discriminated to have noise therein and the original signal passes as it is when not to eliminate noise without incurring deterioration in the picture due to the movement.
Abstract: PURPOSE:To suppress production of distortion in a movement part of a picture while keeping the noise reduction effect by providing a circuit extracting a signal commanding a position of a picture element including noise from a signal difference between an original signal and an output signal at a median filter and using the signal to select either an input or an output of the median filter. CONSTITUTION:A minimum value circuit 40 eliminates impulse noise by one scanning line width included in a distortion signal. A maximum value filter 50 expands the width. As a result the obtained signal is very close to the distortion generated fro a median filter 10 at the moving region. A subtractor 60 subtracts an output of a maximum value circuit 50 from an output of an absolute value circuit 30 to extract only a signal corresponding to impulse noise. An output of the median filter 10 is used for a picture element discriminated to have noise therein and the original signal passes as it is when not to eliminate noise without incurring deterioration in the picture due to the movement.

Journal ArticleDOI
TL;DR: In this paper, the efficiency of trellis-coded modulation (TCM) schemes against Gaussian noise has been well known, however, its performance for impulse noises, which degrade the quality of urban radios, wire communications, and so on, remains unknown.
Abstract: The efficiency of trellis-coded modulation (TCM) schemes against Gaussian noise has been well known. However, its performance for impulse noises, which degrade the quality of urban radios, wire communications, and so on, remains unknown. This paper pays special attention to a trellis-coded QPSK modulation scheme, for example, and clarifies the analysis method of lower bounds of bit error rates. Also, computer simulations were made to verify the analytical results. As a result, the efficiency of the TCM scheme against the impulse noise has been clarified.

Journal ArticleDOI
TL;DR: Familiarity, ease of access, trust, and awareness of risks and benefits will all be important.
Abstract: 衝撃工具から発せられる衝撃騒音をテープに記録し, その波形パターンと衝撃周期を調査した. その結果, 波形パターンは指数減衰型が多く, 衝撃周期は500ms未満であることを明らかにした.次に衝撃騒音のラウドネスを調べるため, 調査した波形に類似し, RMS値の等しいモデル波形を作成し, 被験者調整法によるラウドネス実験を行った. 実験結果によると, 等RMSの波形であっても, 衝撃周期が増加するほどラウドネスも増加することを明らかにした.さらに, 衝撃周期とラウドネスの関係から, 指数減衰型の繰り返し衝撃波形入力に伴う聴覚の応答特性を検討した. 聴覚の立ち上がりの時定数を90msとした場合, 実験結果との整合性が得られることを明らかにした.