Showing papers on "Impulse noise published in 1968"
TL;DR: In this paper, the impulse noise damage risk criteria based on conclusions of independent British and American studies and on the work of other research workers in this field are presented, and the variables that must be considered in determining the potential hearing hazard and in the practical application of the criteria are presented.
Abstract: This paper presents impulse‐noise damage‐risk criteria based on conclusions of independent British and American studies and on the work of other research workers in this field. Most of the studies that led to this criterion were performed with noise from small arms, but the criterion is general enough to permit assessment of most other types of impulse noise. The variables that must be considered in determining the potential hearing hazard and in the practical application of the criteria are presented, and the parameters that must be measured are defined. The measurement technique and type of transducers to be used are discussed.
103 citations
01 Jul 1968
TL;DR: In this paper, proposed criteria (definitions, basic criterion, and correction factors) are defined and justification and limitations are provided. But the proposed criteria are not applicable to the case of this paper.
Abstract: : Contents: Proposed criteria (definitions, basic criterion, and correction factors); Explanation and justification; and Limitations.
57 citations
TL;DR: A systemwide survey of the transmission performance of Bell System intertoll trunks was undertaken in 1964 as discussed by the authors, where the physical composition and some physical attributes of the trunks were given.
Abstract: A systemwide survey of the transmission performance of Bell System intertoll trunks was undertaken in 1964. The sample design used for the survey is described briefly. The main purpose of the paper is to present survey results. Thus, the physical composition and some physical attributes of the trunks are given. The transmission measurement procedures are summarized, and measurement results are presented in distributional form for 1000-Hz loss, frequency response, background noise, impulse noise, and relative envelope delay. Among the results noted are an increase in average noise level and a decrease in noise level standard deviation as the trunk length is increased. The frequency response of long trunks is superior to that of short trunks. Measurement results are presented separately for major transmission facilities.
10 citations
TL;DR: A memoryless filter is proposed which attenuates the input signal more severely when a second input to the filter indicates the channel is having a noise burst, and performance will not degrade with decreased noise when the nonlinearity is odd and monotonic.
Abstract: In linear-real coding, the transmitted signals are (possibly redundant) linear combinations of the data signals. The linear combination of data signals can have a block pattern, resulting in linear-real block coders, or a stationary pattern, resulting in linear-real stationary (shift-register) coders. Stationary coding is shown to be a limiting case of block coding. Both methods appear to be practical for the control of burst and impulse noise. However, stationary coding appears to have some advantages and is the only one we study here. We propose shift register implementations which promise the required precision and dispersion at less cost than tuned RLC circuits. Error properties of both block and stationary coders are similar, but it is easier to learn concepts by analyzing the block coders. When the receiver is able, by using some of the techniques we discuss, to estimate the noise covariance matrix for each codeblock, the resulting noise power is less than that for receivers not using the statistics for each codeblock. Nonlinear memoryless filters, such as clippers, are especially effective when used with linear-real coders. We propose a memoryless filter which attenuates the input signal more severely when a second input to the filter indicates the channel is having a noise burst. If the memoryless filter is designed for the worst case noise, then performance will not degrade with decreased noise when the nonlinearity is odd and monotonic.
4 citations
TL;DR: For exposure to very short duration steady-state noise, for noise superimposed with impulsive components, and for high-intensity impulsive noise, there is little information regarding damage risk and the problems associated with the assessment of deafness due to impulse noise will be discussed in this paper.
Abstract: The evaluation of the hazards to hearing experienced by exposure of the ear to noise has resulted in the specification of the physical characteristics of the noise in terms of damage risk criteria. In the case of steady state and relatively long on-period intermittent noises the researches carried out have resulted in the formulation of many such criteria (Glorig, Ward & Nixon 1962; Burns 1965; C. H. A. B. A. 1965? Kryter, Ward, Miller & Eldredge 1966), the interpretation of which in terms of an internationally agreed standard is at present being undertaken by the International Organization for Standardization (I. S. O.). For exposure to very short duration steady-state noise, for noise superimposed with impulsive components, and for high-intensity impulsive noise, there is little information regarding damage risk. What does exist and the problems associated with the assessment of deafness due to impulse noise will be discussed in this paper. It must be borne in mind, however, that no criterion will clearly demark safety from danger and, being based on the light of the best available knowledge, may be subject to change as new evidence becomes available.
4 citations
TL;DR: A family of practical data-transmission systems, whose design is motivated by a desire to reduce the required energy per bit (for a specified noise power density) while operating in a well-defined part of the frequency spectrum, is described.
Abstract: A family of practical data-transmission systems, whose design is motivated by a desire to reduce the required energy per bit (for a specified noise power density) while operating in a well-defined part of the frequency spectrum, is described. The blocks of j information bits that are periodically fed to the transmitter are encoded into equal energy waveforms whose design is based upon the use of truncated \sin(kt + b)/(kt + b) impulse response networks, together with an n -dimensional unit hypersphere code. The same waveform generation equipment is used for matched filtering at the receiver terminal. This design approach leads to equipment that performs well in the presence of impulse noise as well as Gaussian noise.