Investigating the relationship between carrier frequency and effective bandwidth of peripheral filtering in an amplitude‐modulation notch detection task.

2011 ◽  
Vol 129 (4) ◽  
pp. 2489-2489
Author(s):  
Allison I. Shim ◽  
Bruce G. Berg ◽  
Ewa M. Borucki
Keyword(s):  
Amplitude Modulation ◽  
Carrier Frequency ◽  
Detection Task ◽  
Effective Bandwidth ◽  
The Relationship

The Response of Nonlinear Systems to Modulated High-Frequency Input

1993 ◽  
Author(s):  
S. A. Nayfeh ◽  
A. H. Nayfeh
Keyword(s):  
Nonlinear Systems ◽  
Natural Frequency ◽  
Amplitude Modulation ◽  
Carrier Frequency ◽  
High Frequency ◽  
Degree Of Freedom ◽  
Resonant Excitation ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Different Types

Abstract We study the response of a single-degree-of-freedom system with cubic nonlinearities to an amplitude-modulated excitation whose carrier frequency is much higher than the natural frequency of the system. The only restriction on the amplitude modulation is that it contain frequencies much lower than the carrier frequency of the excitation. We apply the theory to different types of amplitude modulation and find that resonant excitation of the system may occur under some conditions.

scholarly journals Sound Design for Vocalizations: Quality in the Woods, Consistency in the Fields

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Timothy J. Brown ◽  
Paul Handford
Keyword(s):  
Long Range ◽  
Amplitude Modulation ◽  
Carrier Frequency ◽  
Sound Design ◽  
Habitat Types ◽  
Acoustic Adaptation ◽  
Acoustic Adaptation Hypothesis ◽  
Closed Habitat ◽  
Long Range Communication ◽  
Low Rate

AbstractThe acoustic adaptation hypothesis (AAH) predicts that vocalizations intended for unambiguous long range communication should possess amplitude modulation (AM) characteristics such that the temporal patterning of amplitude degrades less than alternative patterns during transmission through native habitat. The specific predictions are that open habitat signals should be structured as rapid AM trills, whereas closed habitat signals should be structured as low-rate AM tonal whistles. To investigate the benefit of trill- and whistle-structured signals in open and closed habitats, respectively, a high and low carrier frequency set of four synthetic signals which ranged from rapid AM trills to low rate AM whistles were transmitted 3 hours after sunrise through five different habitat types ranging from closed mature forest to open grassland. Results indicate that, on average, whistles degrade less than trills in both habitats. Trills benefit in open habitats through their tendency to be received with a more consistent quality than whistles. Such differences in transmission consistency among AM patterns are not found in closed habitats. While not degrading less on average, lower frequency signals are received with a more consistent quality than are higher frequency signals of the same AM structure, in both open and closed habitats.

scholarly journals The relationship between alertness and spatial attention under simulated shiftwork

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
D. Chandrakumar ◽  
J. Dorrian ◽  
S. Banks ◽  
H. A. D. Keage ◽  
S. Coussens ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Health And Safety ◽  
Reaction Times ◽  
Vigilance Task ◽  
Detection Task ◽  
Future Research ◽  
Tentative Evidence ◽  
Stanford Sleepiness Scale ◽  
Psychomotor Vigilance ◽  
The Relationship

Abstract Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M = 24.6 ± 5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness; suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left side and a narrowing of attention with lowered alertness. The possibility that one’s ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.

The Relationship between Psychoacoustic and Electrophysiological Assessments of Temporal Resolution

2021 ◽  
Author(s):  
Kamran Heydari ◽  
Ali Akbar Tahaei ◽  
Akram Pourbakht ◽  
Hamid Haghani ◽  
Ahmadreza Nazeri
Keyword(s):  
Temporal Resolution ◽  
Carrier Frequency ◽  
Significant Positive Correlation ◽  
Modulation Depth ◽  
Detection Threshold ◽  
Positive Correlation ◽  
Phase Increment ◽  
Electrophysiological Measurements ◽  
Modulation Rate ◽  
The Relationship

Abstract Background Temporal resolution is essential to speech acoustic perception. However, it may alter in individuals with auditory disorders, impairing the development of spoken and written language. The envelope of speech signals contains amplitude modulation (AM) that has critical information. Any problem reducing the listener's sensitivity to these amplitude variations (auditory temporal acuity) is likely to cause speech comprehension problems. The modulation detection threshold (MDT) test is a measure for evaluating temporal resolution. However, this test cannot be used for patients with poor cooperation; therefore, objective evaluation of MDT is essential. Purpose The main aim of this study is to find the association between the auditory steady-state response (ASSR) and psychoacoustic measurement of MDT at different intensity levels and to assess the amplitude and phase of ASSR as a function of modulation depth. Design This was a correlational research. Study Sample Eighteen individuals (nine males and nine females) with normal hearing sensitivity, aged between 18 and 23 years, participated in this study. Data Collection and Analysis ASSR was recorded at fixed AM rates and variable AM depths for carrier frequencies of 1,000 and 2,000 Hz with varying intensities. The least AM depth, efficient to evoke an ASSR response, was interpreted as the physiological detection threshold of AM. The ASSR amplitude and phase, as a function of AM depth, were also evaluated at an intensity level of 60 dB hearing level (HL) with modulation rates of 40 and 100 Hz. Moreover, the Natus instrument (Biologic Systems) was used for the electrophysiological measurements. An AC40 clinical audiometer (Intra-acoustic, Denmark) was also used for the psychoacoustic measurement of MDT in a similar setting to ASSR, using the two-alternative forced choice method. Pearson's correlation test and linear regression model and paired t-test were used for statistical analyses. Results A significant positive correlation was found between psychoacoustic and electrophysiological measurements at a carrier frequency of 1000 Hz, with a modulation rate of 40 Hz at intensity levels of 60 dB HL (r = 0.63, p = 0.004), 50 dB HL (r = 0.52, p = 0.02). A significant positive correlation was also found at a carrier frequency of 2000 Hz, with a modulation rate of 47 Hz at 60 dB HL (r = 0.55, p = 0.01) and 50 dB HL (r = 0.67, p = 0.002) and a modulation rate of 97 Hz at 60 dB HL (r = 0.65, p = 0.003). Moreover, a significant association was found between the modulation depth and ASSR amplitude and phase increment at carrier frequencies of 1,000 and 2000 Hz, with modulation rates of 40 and 100 Hz. Conclusion There was a significant correlation between ASSR and behavioral measurement of MDT, even at low intensities with low modulation rates of 40 and 47 Hz. The ASSR amplitude and phase increment was a function of modulation depth increase. The findings of this study can be used as a basis for evaluating the relationship between two approaches in the clinical population.

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