The effect of amplitude envelope on the pitch of sine wave tones

1978 ◽  
Vol 63 (4) ◽  
pp. 1105-1113 ◽  
Author(s):  
W. M. Hartmann
Keyword(s):  
2021 ◽  
Vol 263 (2) ◽  
pp. 4634-4640
Author(s):  
Nozomiko Yasui ◽  
Masanobu Miura ◽  
Tetsuya Shimamura

The motor sound on electric powered vehicle is quiet at low speeds. Thus, pedestrians have difficulty detecting the vehicles approaching them under urban noise. Although the vehicles were designed to play an alert sound to solve this problem, it has not been solved yet. Our previous studies found that characteristics of amplitude fluctuation, fluctuation frequency, non-periodic fluctuation and amplitude envelope, are effective to make them detect approaching vehicles. However, those studies were investigated under only a specific actual environment, weren't examined validity of detectability in those studies. Here, this paper investigates under another actual environment, examine the validity. Investigations were carried out by using synthesized complex sounds which were designed to have periodic and non-periodic amplitude fluctuations. Those complex sounds have characteristics of amplitude fluctuations in gasoline powered vehicle. Amplitude envelopes such as modulation wave in amplitude-modulated sound were set for deviations for time and amplitude, and amplitude-modulated complex sounds were synthesized using sine wave, sawtooth wave, and rectangle wave. Then, their effects on detectability by pedestrians were assessed in another actual environment. The results found that amplitude fluctuation enhances the ability with which people detect approaching electric powered vehicles in case of some complex sound.


1991 ◽  
Vol 34 (2) ◽  
pp. 415-426 ◽  
Author(s):  
Richard L. Freyman ◽  
G. Patrick Nerbonne ◽  
Heather A. Cote

This investigation examined the degree to which modification of the consonant-vowel (C-V) intensity ratio affected consonant recognition under conditions in which listeners were forced to rely more heavily on waveform envelope cues than on spectral cues. The stimuli were 22 vowel-consonant-vowel utterances, which had been mixed at six different signal-to-noise ratios with white noise that had been modulated by the speech waveform envelope. The resulting waveforms preserved the gross speech envelope shape, but spectral cues were limited by the white-noise masking. In a second stimulus set, the consonant portion of each utterance was amplified by 10 dB. Sixteen subjects with normal hearing listened to the unmodified stimuli, and 16 listened to the amplified-consonant stimuli. Recognition performance was reduced in the amplified-consonant condition for some consonants, presumably because waveform envelope cues had been distorted. However, for other consonants, especially the voiced stops, consonant amplification improved recognition. Patterns of errors were altered for several consonant groups, including some that showed only small changes in recognition scores. The results indicate that when spectral cues are compromised, nonlinear amplification can alter waveform envelope cues for consonant recognition.


2009 ◽  
Author(s):  
Navin Viswanathan ◽  
James S. Magnuson ◽  
Carol A. Fowler
Keyword(s):  

Author(s):  
Enyu Ma ◽  
Hui Zhao ◽  
Shuo Chen ◽  
Shuai Wang ◽  
Xin Huo ◽  
...  
Keyword(s):  

2012 ◽  
Vol 37 (4) ◽  
pp. 447-454
Author(s):  
James W. Beauchamp

Abstract Source/filter models have frequently been used to model sound production of the vocal apparatus and musical instruments. Beginning in 1968, in an effort to measure the transfer function (i.e., transmission response or filter characteristic) of a trombone while being played by expert musicians, sound pressure signals from the mouthpiece and the trombone bell output were recorded in an anechoic room and then subjected to harmonic spectrum analysis. Output/input ratios of the signals’ harmonic amplitudes plotted vs. harmonic frequency then became points on the trombone’s transfer function. The first such recordings were made on analog 1/4 inch stereo magnetic tape. In 2000 digital recordings of trombone mouthpiece and anechoic output signals were made that provide a more accurate measurement of the trombone filter characteristic. Results show that the filter is a high-pass type with a cutoff frequency around 1000 Hz. Whereas the characteristic below cutoff is quite stable, above cutoff it is extremely variable, depending on level. In addition, measurements made using a swept-sine-wave system in 1972 verified the high-pass behavior, but they also showed a series of resonances whose minima correspond to the harmonic frequencies which occur under performance conditions. For frequencies below cutoff the two types of measurements corresponded well, but above cutoff there was a considerable difference. The general effect is that output harmonics above cutoff are greater than would be expected from linear filter theory, and this effect becomes stronger as input pressure increases. In the 1990s and early 2000s this nonlinear effect was verified by theory and measurements which showed that nonlinear propagation takes place in the trombone, causing a wave steepening effect at high amplitudes, thus increasing the relative strengths of the upper harmonics.


2018 ◽  
Vol 3 (2) ◽  
pp. 1-6
Author(s):  
Raji A. Abimbola

In recent years, Nigeria’s power generation output from all the available energy sources such as coal, natural gas, and water, is far from the expected number required to meet the energy demand of her teeming populace. This culminates in long hours of power outages frequently experienced in many parts of the country. However, there appears to be no end in sight to the problem. Alternatively, few citizens who can afford generator have wittingly resulted to the use of this device to supply power. Generator set has unavoidable disadvantages of high maintenance or running cost, noise pollution, and release of dangerous gases that pose danger to human lives. Evidently, that solution is risky and inadequate. Power inverter is an alternative and better means of generating electricity with little or no maintenance cost, environment or eco- friendly and poses no risk to human health. It is in that connection that we develop in this work 2KVA sine wave inversion system which produces sinusoidal A.C. signal required in homes for lightning and powering electronic gadgets like television, radio, refrigerator, Air conditioner etc. It is an improvement over square wave and modified sine wave inversion systems that generate digital approximations of A.C. signal. An interesting but new addition is the use of LCD display, interfaced with PIC16F688 microcontroller for showing the design specifications of the inverter.


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