Showing papers on "Noise published in 1982"

Community annoyance from aircraft and ground vehicle noise

Abstract: Data from published noise‐annoyance surveys are related to a common measure of noise exposure Ldn. The results provide means for predicting the annoyance (experienced by percentages of people of normal and of supersensitivity) attributable to noise from aircraft and from street and road traffic. Correlations of 0.90 to 0.95 are found between Ldn and percentages of people annoyed by aircraft noise when low, moderate, and higher levels of annoyance are measured for both a broad range (35 dB) and a restricted range (20 dB) of Ldn. Noise from urban street and road traffic is shown to cause less annoyance than the noise from aircrafts when both have the same Ldn as typically measured or estimated for outdoors. The difference, equivalent to a difference of about 10 dB in Ldn, is attributed to acoustical factors that diminish in‐and‐around‐the‐home noise dosages from ground vehicular traffic compared to dosages from aircraft operations. Generalized functions showing degrees of annoyance and percentages of U.S. u...

Effects of Aircraft Noise on Reading Ability of School–Age Children

Abstract: The percent of students reading below grade level from 1972 to 1976 was regressed on racial, socioeconomic, educational, and noise level variables for all elementary schools in Brooklyn and Queens, New York. Schools were assigned noise exposure scores based on Noise Exposure Forecast contours for New York City airports. The correlations between these noise scores and a variety of noise level metrics ranged from 0.74 to 0.97. The regression coefficients adjusted for confounding factors, indicated that an additional 3.6% of the students in the noisiest schools read at least 1 yr below grade level with 95% confidence limits from 1.5 to 5.8%. The dose-response relationship indicated that the percent reading below grade level increased as noise level increased.

The Lombard Sign as a Function of Age and Task

Abstract: The Lombard sign was investigated as a function of age and task. Twenty adults and 20 5-year-old children spoke in quiet and in the presence of a 90-dB SPL noise. Half the subjects labelled a serie...

Quantitative noise analysis in a modern hospital.

Abstract: Quantitative noise analysis of a general surgical ward in a modern hospital showed that the level of noise was in excess of recommended levels and of sufficient intensity to disturb sleep. Individual noises in excess of 50 dB(A) were recorded in every area at all times of the day. Internal hospital sounds were responsible for most noise; staff and audible warning devices were the main sources of noise over 70 dB(A). Octave waveband analysis showed that both the general ward noise and the noise of the air conditioning were in excess of recommended levels.

The minimum detectable duration of auditory signals for normal and hearing-impaired listeners

Abstract: The minimum detectable duration of a brief burst of noise and a brief gap in a noise were measured by the two‐alternative forced‐choice method. For all listeners the minimum detectable duration of a burst was shorter than the minimum detectable duration of a gap at equal signal‐to‐noise ratios. For 12 listeners with normal hearing, the average minimum detectable duration of a burst with a 10‐dB signal‐to‐noise ratio was 1.2 msec, whereas the average of a gap at the same signal‐to‐noise ratio was 4.2 msec. Nine of ten hearing‐impaired listeners required longer durations, whether for bursts or gaps, than the average of normal listeners. These nine impaired listeners had slower time constants than any of the normal listeners. Both the rise and decay of auditory sensation in the impaired listeners were therefore abnormally slow.

Noise and Degeneration: Theodor Lessing's Crusade for Quiet

Abstract: to Hindenburg’s presidency, and who was assassinated in exile in Czechoslovakia by two local Nazis in 1933. This legacy, as well as the reputation of his books on historicism, Jewish self-hatred, and European and Asian culture, have obscured his role as a pioneer in the noise abatement movement at the beginning of the twentieth century. To Lessing, the din of the metropolis was an effect and a cause of the degeneration of the quality of life in Western civilization. The Deutscher Ldrmschutzverband which he founded represented not only a reformist crusade for quiet, but also a fundamental critique of the modernization process itself and of the ideas which promoted it.4 4

A Study of Annoyance Due to Low Frequency Noise in the Home

Abstract: A survey of complaints of low frequency noise was followed by noise measurements in complainants' homes. The survey showed that annoyance was greatest in the late evening and early morning, leading...

Video and sound recording device with automatic focusing system

Abstract: There are video and sound recording devices such as movie cameras or video cameras with an automatic focusing system of the type for setting a photographic lens to a position at which an object can be sharply focused in response to the signal which is representative of a distance from the camera to the object and obtained by measuring the time interval from the time when the ultrasonic waves are transmitted at a predetermined repetition frequency to the object to the time when the echo from the object is received. Such devices have a common defect that a microphone picks up impulse-like noise generated from an ultrasonic transducer especially at the start point of ultrasonic waves. To overcome this problem, the present invention provides an audible noise elimination or suppression means or a control circuit which operates in synchronism with the ultrasonic wave transmission so that an audio signal processing system attenuates the audio output signal.

Differentiation of Types of Presbycusis Using the Masking-Level Difference

Abstract: Masking-level differences in quiet at 500 Hz were used to demonstrate evidence of elevated noise levels within the auditory systems of subjects with assumed neural presbycusis. The following five g...

Effect of intermittent (traffic) noise on man--temporary threshold shift, and change in urinary 17-OHCS and saliva cortisol levels.

Abstract: Eight healthy male college students were selected and eight noise exposure conditions were planned. The noise exposure time of all the experiments was 14 h. Measurement of the TTS growth at 4 kHz was investigated during these 14 h. Saliva collected every 3 h was also examined for cortisol throughout the 24-h period. The exposure noises used in this experiment were pink noise and pure tone of 3 kHz. The time patterns of trapezoidal noise were as follows. The rise and decay times were 1 s respectively and the peak level was 1 s for the (A I type), being 500 ms and 1.5 s respectively for the (A II type).

Spectral analysis of impulse noise for hearing conservation purposes

Abstract: Damage-risk criteria for impulse noise does not presently take the spectrum of the impulse into account; however, it is known that the human auditory system is spectrally tuned. The present paper advocates the extension to impulse noise of the noise dose concept which is widely used for continuous noise. This approach is based upon sound exposure instead of sound pressure. An A-weighting filter or an octave band analysis can then be used to take the spectral content of the impulses into account. The equipment needed for applying these procedures for impulse noise is an integrating sound level meter or a digital Fourier processor. Generalized spectral methods have been evaluated by means of an impulse simulation applied to a mathematical model of the human hearing mechanism. The results of this simulation agree with the most recent experiments on impulse noise and fully support the proposed rating methods. This conclusion must be emphasized as it leads the derivation of a uniform procedure for predicting loudness and damage risk for hearing which is applicable for continuous noise as well as for impulse noise.

A solid-state image sensor for image recording at 2000 frames per second

Abstract: We describe a solid-state sensor for image recording at frame rates up to 2000 full or 12 000 partial frames per second (fps). The sensor consists of a 192 V × 248 H array of photocapacitors. For high-speed operation the image-sensing area is divided into 6 blocks, each with 32 parallel outputs. The blocks are addressed sequentially, and the 32 outputs are sensed simultaneously. The sensor dynamic range is 46 dB at 2000 fps. Data on sensor speed, spectral sensitivity, noise, and spatial resolution are presented and compared with those of models.

Heart Rate- and ECG-Recording in the Rat by Biotelemetry

Abstract: A method for 24 h recording of the heart rate (HR) in unrestrained, freely moving rats is described. Commercially available biotelemetry transmitters were used in combination with normal ranged FM-receivers. The data presented show a pronounced diurnal rhythm in the HR of the rat. When the rats are exposed to noise a large increase in the HR could be demonstrated. The system described is also suitable for analysis of the time parameters of the electro-cardiogram (ECG).

Differences in Speech Discrimination in the Elderly as a Function of Type of Competing Noise: Speech-Babble or Cafeteria

Abstract: Speech discrimination of place-loaded Modified Rhyme test words in speech-babble and cafeteria noise by elderly hearing-impaired subjects was measured. The stimuli were presented under the following conditions: (1) monotic: the signal was presented to the preferred ear; (2) low-frequency attenuated: the frequency band below 1,000 Hz was attenuated by 5, 10, and 15 dB relative to the high-frequency band; (3) dichotic: the frequency band above 1,000 Hz was presented to the preferred ear and the low-frequency band to the other ear; (4) diotic: the same signal was presented to both ears. Difference scores between the monotic baseline condition and the other listening modes were calculated and compared. Relationships between listening modes differed as a function of type of competing noise. Low-frequency attenuation improved discrimination in speech-babble but not in cafeteria noise. Dichotic-monotic and diotic-monotic superiority were seen with both noises.

Auditory threshold and the degree of its temporary and permanent shifts in the textile industry workers

Abstract: Hearing threshold was measured with digital audiometer CASK-431 in transportable soundproof booth GIG-AU-1 in 170 women and 75 men before and at the end of the afternoon shift work in the weaving-mill with shuttle looms, where an average noise level was 100 dB(A). The average hearing losses calculated from the formula dB (1000 Hz + 2000 Hz + 4000 Hz): 3 were higher than those calculated from the formula db (500 Hz + 1000 Hz + 2000 Hz): 3. There was also a higher correlation coefficient between the occupational exposure to noise and the values of hearing loss calculated according to the former of the mentioned formulae, as compared to the latter. Workers wearing individual hearing protectors from the glass microfibres suffered from temporary threshold shift (TTS) of few dB whereas in those wearing no hearing protectors the TTS attained 10 to 24 dB on average. Among the women--workers of comparable age and occupational exposure to noise the hearing losses were higher in those living in noisy communities than in those living in quiet communities. This result is indicative of cumulative effects of community and industrial noise in respect to the hearing damage. Regulations for permissible noise levels in occupational environment should involve the kind of exposure to the community noise.

Method and apparatus for noise reduction by head phone

Abstract: PURPOSE:To reduce noise to ears and to effectively listen to required information only, by providing a microphone at the outside of a headphone speaker unit and inputting a signal incident to the microphone to the speaker unit through phase inversion CONSTITUTION:Microphones 4,4' are located outside headphone speaker units 2,2' of a headphone 1, and the output is inputted to addition amplifiers 6,6' of corresponding left and right channels via phase inversion circuits 5,5' With such a construction, if a noise N takes place externally, a noise wave 9 is incident to a microphone 4, and a signal in phase reflection at the circuits 5,5' is formed, and it is applied to the units 2,2' together with the information from a music information supply 3 to cancel noise 8 applied to ears 8, allowing to effectively listen to required audio or music information only

Controller of audio device and the like

Abstract: PURPOSE:To avoid the noise in case various types of audio devices are controlled by a microcomputer, by always keeping logic 1 for each output port of the microcomputer during the key scanning of a normal operation. CONSTITUTION:In case various types of audio devices are controlled by a microcomputer, the routine through which the key scanning of a normal operation is made to turn around a loop. The output ports A and B of a microcomputer are set to keep logic 1 at all times. Thus the routine never gets out of the loop unless either one of the keys on a keyboard 2 is pushed, and accordingly the outputs of the ports A and B have no change. As a result, no noise is produced. When either one of the keys on the keyboard 2 is pushed, whether the signal is given from the port A or B is discriminated. The time required for the discrimination is within several hundreds of s, and the noise may possibly be caused only when the ports A and B have a change, respectively. This noise is, however, can be neglected at all.

Control signal recording system

Abstract: PURPOSE:To control channel selections, etc, easily and securely by recording control signals for exercising control over channel selections, program searches, etc, on respective channels of a magnetic tape, on which audio stereophonic signals are recorded, at the same frequency with the opposite phases CONSTITUTION:On channels 2R and 2L of a magnetic tape 1 for recording a right and a left signal, the right and left signals 3R and 3L of an audio stereophonic signal are recorded Then, control signals 4R and 4L consisting of low-frequency sine waves, etc, are recorded on the channels 2R and 2L at the same frequency with the opposite phases In the reproduction of the tape 1, out-of-phase signals are reproduced from a right and a left speaker to cancel mutually, so that no noise is generated Further, the difference from the audio stereophonic signal is secured and a head dedicated to detection is unnecessary Consequently, control over channel selections, program searches, etc, is exercised easily and securely at a low cost

Recognition memory for prose items in noise

Abstract: Using a probe-recognition technique the signal detection theory parameters d' and Beta were estimated for three types of probe (common surnames, uncommon surnames and synonyms) for material contained in a prose passage. Subjects were presented with the prose passage either in the presence of noise (85dBA) or in quiet (60dBA). In two experiments the effects of noise on auditory and visual presentation of the passage were studied. In both cases the recognition test took place in quiet. Noise decreased values of Beta for rare names and increased Beta for common names in both auditory and visual versions of the task. Noise influenced d' values in the auditory version only, with d' increasing for common names in loud noise. The results support the view that noise influences performance by disturbing the pigeon-holing mechanism with the qualification that when material may not be recapitulated (as in the auditory presentation in the present study) greater attention may be allocated to easily recognizable material. The findings give little support to theories of noiseinduced deficits in performance based on the masking of inner speech.

That melodious noise: DUET (the Development of University English Teaching project)

Abstract: This article gives a brief account of the DUET 1 and DUET 2 workshops held under the Development of University English Teaching project: and introduces a small anthology drawn from the reports written about DUET 1.

Blank noise tests for spectral analysis

Abstract: Blank noise tests are derived for two types of spectral functions as defined by Vanicek. Their probability density has the beta-distribution which is easily related to Fisher distribution. Two examples are discussed.

Noise rejecting circuit

Abstract: PURPOSE:To reduce noise without voice and audio buzz sound at nonsignal and detuning, by connecting a tuning circuit tuned to frequency of a multiple of horizontal scanning frequency to the output of audio intermediate frequency detection, and attenuating the audio detected output through the detection of noise outside the audio band. CONSTITUTION:When a tuner input signal becomes small or no signal is present, a DC voltage in proportion to the noise component is obtained at an output terminal of a detection circuit 8. When this voltage is at a certain level or more, the gain of an audio amplifier 6 is attenuated in response to amount of noise to reduce the noise to a level or lower. If detuning is made near a broadcasting signal, a horizontal scanning frequency and a signal of multiple of it are picked up from a tuning amplifying circuit 7, and when the buzz component is a level or more, the gain of the circuit 6 is attenuated or cut off depending on the amount of buzz component.

Audio signal recording and reproducing circuit

Abstract: PURPOSE:To reduce adjacent interference noise of VTR of an audio FM multiplex system, by using a noise rejecting circuit affecting to an audio signal for recording and reproduction CONSTITUTION:After the dynamic range of an audio signal from an input terminal 1 is compressed into 1/2 at a 1/2 compression circuit 2, it is modulated at an FM modulator 3 Ater the output of the modulator 3 is added with a video signal at an adder 4, it is recorded on a magnetic tape 6 with a magnetic head 5 A signal reproduced from the tape 6 is given to a BPF 8 An FM audio signal picked up at the BPF is demodulatd into the audio signal at an FM demodulator 9 and the signal is expanded for the original dynamic range at a double expanding circuit 10 Thus, the adjacent interference noise is reduced by using a noise rejecting circuit consisting of the compression circuit 2 and the expanding circuit 10

Video disc player with compensation for stylus holder mechanical resonance

Abstract: A video disc player includes a pick-up cartridge in which the stylus is supported by a stylus holder that is mechanically resonant at a frequency within an audio frequency range. A pick-up converter coupled to the stylus provides a broad audio video output signal that is undesirably modulated due to the stylus holder mechanical resonance. The audio signal is demodulated to baseband and linearly combined with the un-demodulated broadband signal to provide a resultant audio output signal in which audio frequency noise components, due to the mechanical resonance of the resulus holder, are attenuated.

Audio alarming unit for running equipment

Abstract: PURPOSE:To prevent the sound of alarm from being drowned by noise by automatically shifting to an audio alarming system when the failure of each part of running equipment is detected in a passenger truck provided with audio equipment such as radio. CONSTITUTION:When the main switch 15 is closed, speakers 7 and 7a broadcast stereo music. When an emergency such as lack of fuel occurs, the signal of a detector operates an audio alarm unit 11 and selects a switchover system 9. The speakers 7 and 7a are disconnected from a sound generation system 8 and connected to an alarm system 11. Only an alarm sound is broadcasted responding to shortage of fuel by the direction of computer. Therefore, the operator can hear the generation of failure and take a prompt and proper step.