Amplitude Modulation Detection Research Articles

The impact of M-ary rates on various quadrature amplitude modulation detection

The 5G system-based cognitive radio network is promised to meet the requirements of huge data applications with spectrum. However, the M-ary effect on the detection has not been thoroughly investigated. In this paper, an M-ary of quadrature amplitude modulation detection system is studied. Many rates are used in this study 4, 16, 64, and 256 constellation points. The detection system is applied to cooperative spectrum sensing to enhance the performance of detection for various rates of M-ary with low signal-to-noise ratio (SNR). Further, three kinds of signals based 5G system are sensed: filtered-orthogonal frequency division multiplexing (F-OFDM), filter bank multi-carrier (FBMC), and universal filtered multi-carrier (UFMC). The best detection performance is obtained when the M-ary=4 and number of SUs=50 user, whereas the worst detection performance is obtained when the M-ary=256 and number of SUs=10 user, as revealed in the simulation results. In addition, the detection performance for the F-OFDM signal is better than that of UFMC and FBMC signals for SNR <0 dB.

Quantification of amplitude modulation of wind turbine emissions from acoustic and ground motion recordings

Amplitude modulation (AM) is a common phenomenon associated with wind turbine (WT) related noise annoyance. Within the interdisciplinary project Inter-Wind, acoustic, ground motion, and meteorological data are captured to be evaluated with noise reports of residents living near a wind farm in Southern Germany. The recorded data builds a solid data base for the evaluation of AM. The occurrence of AM is detected within acoustic and ground motion data and set in relation to all available data, including WT operational parameters, meteorology, and noise reports. In this study, the origins of detected AM are tones at 57.8 Hz and 133 Hz, related to the generator and drive train, which are amplitude modulated by the blade passing frequency. AM detection was successful both with acoustic as well as ground motion data. A comparison of a method for AM detection developed by the Institute of Acoustics (IOA reference method) with a method specifically developed to detect AM in ground motion data showed that the reference method detected AM three to six times more often than the newly developed method. AM occurred most likely during stable atmospheric conditions, with a positive lapse rate, and was (albeit to a small degree) more likely to be detected when residents reported higher levels of annoyance.

Cues to reduce modulation informational masking.

The detectability of target amplitude modulation (AM) can be reduced by masker AM in the same carrier-frequency region. It can be reduced even further, however, if the masker-AM rate is uncertain [Conroy and Kidd, J. Acoust. Soc. Am. 149, 3665-3673 (2021)]. This study examined the effectiveness of contextual cues in reducing this latter, uncertainty-related effect (modulation informational masking). Observers were tasked with detecting fixed-rate target sinusoidal amplitude modulation (SAM) in the presence of masker SAM applied simultaneously to the same broadband-noise carrier. A single-interval, two-alternative forced-choice detection procedure was used to measure sensitivity for the target SAM; masker-AM-rate uncertainty was created by randomly selecting the AM rate of the masker SAM on each trial. Relative to an uncued condition, a pretrial cue to the masker SAM significantly improved sensitivity for the target SAM; a cue to the target SAM, however, did not. The delay between the cue-interval offset and trial-interval onset did not affect the size of the masker-cue benefit, suggesting that adaptation of the masker SAM was not responsible. A simple model of within-AM-channel masking captured important trends in the psychophysical data, suggesting that reduced masker-AM-rate uncertainty may have played a relatively minor role in the masker-cue benefit.

Modulation masking produced by a low-frequency pure tone

An intense low-frequency tone can affect the perception of amplitude modulation (AM) applied to a high-frequency carrier. Here, thresholds for detecting AM of a 3000-Hz carrier were measured in the presence of a 50-Hz pure tone at 91 dB SPL. When the carrier was presented at 20 dB sensation level (SL), the thresholds were higher than in the absence of the 50-Hz tone, increased when the AM frequency was increased from 20 to 100 Hz, and did not show a maximum near 50 Hz, as would be expected if the effect of the 50-Hz tone resulted from modulation detection interference. When the AM frequency was fixed at 50 Hz, the AM detection thresholds showed a minimum when the phase of the AM was 90° ahead of the phase of the 50-Hz tone (denoted Δφ = 90°) and a maximum for Δφ = 270°. To assess the role of the outer hair cells (OHCs), AM detection thresholds were measured as a function of Δφ using SLs of 20 and 50 dB for normal-hearing participants and 20 dB for hearing-impaired participants. It was assumed that the latter would have impaired OHC function. The pattern of the results was similar across SLs and groups: AM detection thresholds were 8–10 dB lower for Δφ = 90° than for Δφ = 270° in all cases. This suggests that the OHCs do not play a large role in these effects and supports the idea that the low-frequency tone biases the responses of inner hair cells tuned to high frequencies.

Streamlining experiment design in cognitive hearing science using OpenSesame

Auditory science increasingly builds on concepts and testing paradigms originated in behavioral psychology and cognitive neuroscience – an evolution of which the resulting discipline is now known as cognitive hearing science. Experimental cognitive hearing science paradigms call for hybrid cognitive and psychobehavioral tests such as those relating the attentional system, working memory, and executive functioning to low-level auditory acuity or speech intelligibility. Building complex multi-stimuli experiments can rapidly become time-consuming and error-prone. Platform-based experiment design can help streamline the implementation of cognitive hearing science experimental paradigms, promote the standardization of experiment design practices, and ensure reliability and control. Here, we introduce a set of features for the open-source python-based OpenSesame platform that allows the rapid implementation of custom behavioral and cognitive hearing science tests, including complex multichannel audio stimuli while interfacing with various synchronous inputs/outputs. Our integration includes advanced audio playback capabilities with multiple loudspeakers, an adaptive procedure, compatibility with standard I/Os and their synchronization through implementation of the Lab Streaming Layer protocol. We exemplify the capabilities of this extended OpenSesame platform with an implementation of the three-alternative forced choice amplitude modulation detection test and discuss reliability and performance. The new features are available free of charge from GitHub: https://github.com/elus-om/BRM_OMEXP.

Schaeffer's Solfège, Percussion, Audio Descriptors: Towards an Interactive Musical System

Pierre Schaeffer's typomorphology (1966) proposes seven criteria of musical perception for the identification and qualification of sound objects, which form the basis of his musical theory. This Solfège fits well into contexts where pitch is not the dominant dimension. Relying on similarities between the practice of reduced listening and the utilization of low-level audio descriptors, we present the first version of a real-time setup in which these descriptors are applied to qualify percussive sounds. The paper describes the tools and strategies used for addressing different criteria: envelope followers with different window sizes and filtering; detection of transients and amplitude modulations; extraction and counting of spectral components; estimation of intrinsic dissonance and spectral distribution; among others. The extracted data is subjected to simple statistical analysis, producing scalar values associated with each segmented object. Finally, we present a variety of examples.

Schaeffer's Solfège, Percussion, Audio Descriptors: Towards an Interactive Musical System

Pierre Schaeffer's typomorphology (1966) proposes seven criteria of musical perception for the identification and qualification of sound objects, which form the basis of his musical theory. This Solfège fits well into contexts where pitch is not the dominant dimension. Relying on similarities between the practice of reduced listening and the utilization of low-level audio descriptors, we present the first version of a real-time setup in which these descriptors are applied to qualify percussive sounds. The paper describes the tools and strategies used for addressing different criteria: envelope followers with different window sizes and filtering; detection of transients and amplitude modulations; extraction and counting of spectral components; estimation of intrinsic dissonance and spectral distribution; among others. The extracted data is subjected to simple statistical analysis, producing scalar values associated with each segmented object. Finally, we present a variety of examples.

Cochlear synaptopathy causes loudness perception impairment without hearing loss.

In this study, the development of a quantitative measurement method to predict long-term auditory adaptation through the stimuli that have been modulated according to different short-term modulation types was aimed to form a psychoacoustic test battery. It might be used in the evaluation process of individuals with hidden hearing loss. The individuals participating in our study were separated into two groups: high-risk group (n = 39) and low-risk group (n = 30) according to the noise-exposure score. To all participants, auditory brainstem response (ABR), dichotically digit test, Turkish matrix sentence test, otoacoustic emissions test, amplitude modulation detection test, and loudness adaptation test were applied. Stimuli, used in loudness adaptation tests, were provided in three different experiment pairs (experiment 1-2, experiment 3-4, and experiment 5-6). The amplitude of wave I of ABR increased as the intensity level increased in the low-risk group, whereas the amplitude reduced as the intensity level increased in the high-risk group (P < 0.05). When different carrier frequency stimuli were used in amplitude modulation detection test, we found that loudness adaptation was highest at 1 kHz carrier frequency with background noise (P < 0.05). We observed that individuals assumed having hidden hearing loss had high adaptation scores. It was thought that this result might be related to auditory nerve fibers with low spontaneous rate and thus distortion in temporal coding skills might lead to abnormal loudness adaptation, especially with contralateral noise.

Experimental demonstration of 448 Gb/s PS-PDM-PAM8 coherent transmission over multi-core fiber

The combination of pulse amplitude modulation (PAM) and coherent detection is a promising solution for short reach transmission systems which require the transmission rate of 100 Gb/s and above. In this paper, the transmission of probabilistic shaped polarization-division-multiplexed eight-level pulse amplitude modulated (PS-PDM-PAM-8) signal over multi-core fiber (MCF) using coherent detection is investigated. A modified signal-phase-based LMS (SP-LMS) algorithm is proposed to equalize both intensity-modulated and filed modulated PS-PAM signals. By employing PS and MCF transmission, the total rate of 448 Gb/s is achieved and compared with traditional PDM-PAM4 signal, the PS-PDM-PAM8 can achieve a 22.4 Gb/s gain in net bit rate.

Probing temporal modulation detection in white noise using intrinsic envelope fluctuations: A reverse-correlation study.

Part of the detrimental effect caused by a stationary noise on sound perception results from the masking of relevant amplitude modulations (AM) in the signal by random intrinsic envelope fluctuations arising from the filtering of noise by cochlear channels. This study capitalizes on this phenomenon to probe AM detection strategies for human listeners using a reverse correlation analysis. Eight normal-hearing listeners were asked to detect the presence of a 4-Hz sinusoidal AM target applied to a 1-kHz tone carrier using a yes-no task with 3000 trials/participant. All stimuli were embedded in a white-noise masker. A reverse-correlation analysis was then carried on the data to compute "psychophysical kernels" showing which aspects of the stimulus' temporal envelope influenced the listener's responses. These results were compared to data simulated with different implementations of a modulation-filterbank model. Psychophysical kernels revealed that human listeners were able to track the position of AM peaks in the target, similar to the models. However, they also showed a marked temporal decay and a consistent phase shift compared to the ideal template. In light of the simulated data, this was interpreted as an evidence for the presence of phase uncertainty in the processing of intrinsic envelope fluctuations.

The Impact of Observing Strategy on the Reliable Classification of Standard Candle Stars: Detection of Amplitude, Period, and Phase Modulation (Blazhko Effect) of RR Lyrae Stars with LSST

Abstract The Vera C. Rubin Observatory will carry out its Legacy Survey of Space and Time (LSST) with a single-exposure depth of r ∼ 24.7 and an anticipated baseline of 10 yr, allowing access to the Milky Way’s old halo not only deeper than, but also with a longer baseline and better cadence than, e.g., PS1 3π. This will make the LSST ideal to study populations of variable stars such as RR Lyrae stars (RRL). Here, we address the question of observing strategy optimization of LSST, as survey footprint definition, single-visit exposure time, as well as the cadence of repeat visits in different filters are yet to be finalized. We present metrics used to assess the impact of different observing strategies on the reliable detectability and classification of standard candle variable stars, including detection of amplitude, period, and phase modulation effects of RRL (the so-called Blazhko effect), by evaluating metrics for simulated potential survey designs. So far, due to the depths and cadences of typical all-sky surveys, it has been nearly impossible to study this effect on a larger sample. All-sky surveys with relatively few observations over a moderately long baseline allow only for fitting phase-folded RRL light curves, thus integrating over the complete survey length and hiding any information regarding possible period or phase modulation during the survey. On the other hand, surveys with cadences fit to detect slightly changing light curves usually have a relatively small footprint. LSST’s survey strategy, however, will allow for studying variable stars in a way that makes population studies possible.

Verification of a Mobile Psychoacoustic Test System.

Many hearing difficulties can be explained as a loss of audibility, a problem easily detected and treated using standard audiological procedures. Yet, hearing can be much poorer (or more impaired) than audibility predicts because of deficits in the suprathreshold mechanisms that encode the rapidly changing, spectral, temporal, and binaural aspects of the sound. The ability to evaluate these mechanisms requires well-defined stimuli and strict adherence to rigorous psychometric principles. This project reports on the comparison between a laboratory-based and a mobile system’s results for psychoacoustic assessment in adult listeners with normal hearing. A description of both systems employed is provided. Psychoacoustic tests include frequency discrimination, amplitude modulation detection, binaural encoding, and temporal gap detection. Results reported by the mobile system were not significantly different from those collected with the laboratory-based system for most of the tests and were consistent with those reported in the literature. The mobile system has the potential to be a feasible option for the assessment of suprathreshold auditory encoding abilities.

Temporal integration for amplitude modulation in childhood: Interaction between internal noise and memory

It is still unclear whether the gradual improvement in amplitude-modulation (AM) sensitivity typically found in children up to 10 years of age reflects an improvement in “processing efficiency” (the central ability to use information extracted by sensory mechanisms). This hypothesis was tested by evaluating temporal integration for AM, a capacity relying on memory and decision factors. This was achieved by measuring the effect of increasing the number of AM cycles (2 vs 8) on AM-detection thresholds for three groups of children aged from 5 to 11 years and a group of young adults. AM-detection thresholds were measured using a forced-choice procedure and sinusoidal AM (4 or 32 Hz rate) applied to a 1024-Hz pure-tone carrier. All age groups demonstrated temporal integration for AM at both rates; that is, significant improvements in AM sensitivity with a higher number of AM cycles. However, an effect of age is observed as both 5–6 year olds and adults exhibited more temporal integration compared to 7–8 and 10–11 year olds at both rates. This difference is due to: (i) the 5–6 year olds displaying the worst thresholds with 2 AM cycles, but similar thresholds with 8 cycles compared to the 7–8 and 10–11 year olds, and, (ii) adults showing the best thresholds with 8 AM cycles but similar thresholds with 2 cycles compared to the 7–8 and 10–11 year olds. Computational modelling indicated that higher levels of internal noise combined with poorer short-term memory capacities in children accounted for the developmental trends. Improvement in processing efficiency may therefore account for the development of AM detection in childhood.

Basic auditory processing and emotion recognition in individuals at clinical high risk for psychosis

The ability to understand others' emotions from subtle cues is a critical skill for navigating the complex social world, with increasing demands placed on this capability as children enter adolescence. Individuals at clinical high-risk (CHR) of developing psychosis exhibit social isolation with specific impairments in social cognition (Thompson et al., 2011) and emotion recognition (Addington et al., 2008; Amminger et al., 2011; Corcoran et al., 2015). The degree of social impairment and the severity of emotion recognition deficits are greater in individuals who later convert to psychosis than in those who do not (Cornblatt et al., 2011). Emotion recognition deficits thus represent promising targets for improving early identification and intervention strategies (Addington et al., 2008; Amminger et al., 2011; Cornblatt et al., 2011; Kee et al., 2003; Niemi et al., 2005). A significant challenge remains however, to identify a precursor of emotional recognition deficits for use as a salient diagnostic tool and therapeutic target. Impairments in basic auditory processes may underlie the auditory emotion identification deficits and social functioning deficits associated with psychotic disorders and at-risk states. The auditory properties of speech convey emotional content (Banse and Scherer, 1996; Hammerschmidt and Jurgens, 2007), and the ability to identify emotion from these vocal cues is impaired in schizophrenia (Addington et al., 2008; Amminger et al., 2011; Bach et al., 2009; Corcoran et al., 2015; Cornblatt et al., 2011; Dickey et al., 2010; Dickey et al., 2008; Kee et al., 2003; Leitman et al., 2007; Leitman et al., 2010; Niemi et al., 2005; Thompson et al., 2011), schizotypal personality disorder (Dickey et al., 2010; Dickey et al., 2008), and CHR subjects (Corcoran et al., 2015; Thompson et al., 2011). We recently reported that individuals with schizophrenia exhibit wide ranging basic auditory processing deficits, and that additional basic auditory processing abilities, including formant discrimination, sinusoidal amplitude modulation detection, and duration discrimination are associated with the ability to recognize emotion in voice (Kraus et al., 2019). In this study, we have aimed to determine whether CHR individuals exhibit similar widespread auditory processing deficits associated with impaired emotion recognition.

Double-pass consistency for amplitude- and frequency-modulation detection in normal-hearing listeners.

Amplitude modulation (AM) and frequency modulation (FM) provide crucial auditory information. If FM is encoded as AM, it should be possible to give a unified account of AM and FM perception both in terms of response consistency and performance. These two aspects of behavior were estimated for normal-hearing participants using a constant-stimuli, forced-choice detection task repeated twice with the same stimuli (double pass). Sinusoidal AM or FM with rates of 2 or 20 Hz were applied to a 500-Hz pure-tone carrier and presented at detection threshold. All stimuli were masked by a modulation noise. Percent agreement of responses across passes and percent-correct detection for the two passes were used to estimate consistency and performance, respectively. These data were simulated using a model implementing peripheral processes, a central modulation filterbank, an additive internal noise, and a template-matching device. Different levels of internal noise were required to reproduce AM and FM data, but a single level could account for the 2- and 20-Hz AM data. As for FM, two levels of internal noise were needed to account for detection at slow and fast rates. Finally, the level of internal noise yielding best predictions increased with the level of the modulation-noise masker. Overall, these results suggest that different sources of internal variability are involved for AM and FM detection at low audio frequencies.

Forward masking of amplitude modulation detection includes a large perceptual effect

Forward masking of amplitude modulation (AM) detection is tuned: target sinusoidal AM (SAM) is masked more easily by masker SAM with a similar, rather than dissimilar, rate. This finding has been interpreted either as a sensory effect related to adapting neural units tuned to the target’s AM rate, or as a perceptual effect related to the perceived similarity of the acoustically similar AM. This study investigated these two alternative possibilities. The minimum modulation depth required to detect 96-Hz target SAM was measured following exposure to suprathreshold masker AM applied to the same broadband-noise carrier. Three forward masker modulators were tested: (1) 32-Hz SAM; (2) a 32-Hz square wave; (3) and 96-Hz SAM with a modulation index equivalent to that of the third harmonic of the square wave. The 96-Hz masker SAM produced substantial amounts of forward masking; the 32-Hz sine- and square-waves, however, did not. These findings were inconsistent with the hypothesis that detection of the target SAM was mediated by adapting neural units tuned to the target’s AM rate, suggesting, instead, that forward masking of AM detection includes a large perceptual effect.

Benchmark characterisation and automated detection of wind farm noise amplitude modulation

Amplitude modulation (AM) is a characteristic feature of wind farm noise and has the potential to contribute to annoyance and sleep disturbance. Detection, quantification and characterisation of AM is relevant for regulatory bodies that seek to reduce adverse impacts of wind farm noise and for researchers and wind farm developers that aim to understand and account for this phenomenon. We here present an approach to detect and characterise AM in a comprehensive and long-term wind farm noise data set using human scoring. We established benchmark AM characteristics, which are important for validation and calibration of results obtained using automated methods. We further proposed an advanced AM detection method, which has a predictive power close to the practical limit set by human scoring. Human-based approaches should be considered as benchmark methods for characterising and detecting unique noise features.

Temporal processing, spectral processing, and speech perception in noise abilities among individuals with chronic kidney disease undergoing hemodialysis

Background In the literature, the effect of chronic kidney disease on the peripheral auditory system has been well documented. But studies investigating the effect of chronic kidney disease on speech perception and auditory processing abilities are limited. Aims/objectives The present study investigated the effect of chronic kidney disease on different auditory processing tasks and speech perception in noise among adults. Material and methods A total of 28 adults participated in the study. Group 1 included 14 individuals with chronic kidney disease undergoing hemodialysis, and Group 2 included 14 individuals with no known kidney complications. Amplitude modulation detection threshold, gap detection threshold, spectral ripple discrimination threshold, and speech recognition threshold in noise were measured. Independent samples t-test was carried out to investigate whether mean thresholds are significantly different between groups. Results Results showed poorer gap detection threshold, amplitude modulation detection threshold, spectral ripple discrimination threshold, and speech recognition threshold in noise among individuals with chronic kidney disease compared to individuals with no known kidney complications. Conclusions The present study showed poorer auditory processing and speech perception abilities in individuals with chronic kidney disease.

Efficacy of behavioral audiological tests in identifying cochlear synaptopathy: a systematic review.

Cochlear synaptopathy or hidden hearing loss is difficult to assess due to the lack of sensitivity with standard audiological tests. Poor speech perception, especially in the presence of noise or tinnitus, is the most common complaint of these patients. The purpose of this systematic review is to identify articles in peer-reviewed journals that used behavioral measures in the effective assessment of cochlear synaptopathy or hidden hearing loss. The manuscripts were searched in various international databases, and the manuscripts were screened based on titles, abstracts, and full-length content. A total of 14 human studies were selected after the appropriate exclusion of other articles. Results showed that high-frequency audiometry could be used for the early identification of cochlear synaptopathy. The tone in noise detection test can also be added in the test battery along with speech perception in noise. The amplitude modulation detection test, interaural phase difference, and differential sensitivity tests require more research before using them for the assessment of cochlear synaptopathy or hidden hearing loss. Self-reports and questionnaires also help in determining the extent of noise exposure.

Frequency selectivity in the modulation domain estimated using forward masking: Effects of masker modulation depth and masker-signal delay

The threshold for detecting amplitude modulation (AM) of a sinusoidal or noise carrier is elevated when the signal AM is preceded by masker AM applied to the same carrier. This effect, called AM forward masking, shows selectivity in the AM domain, consistent with the existence of a modulation filter bank (MFB). In this paper we explore the effect of two factors that can influence AM forward masking, using an 8-kHz sinusoidal carrier and a range of masker AM frequencies, fm, both below and above the signal AM frequency, fs, of 40 Hz. The first factor was the time delay, td, between the end of the masker AM and the start of the signal AM. The second was the AM depth, m, of the masker, which was either 1 or 0.25. The AM forward masking patterns in all conditions showed tuning in the AM domain; signal thresholds were highest when fm was close to fs. The amount of AM forward masking decreased with increasing td in a similar way for all fm, so the shapes of the masking patterns did not change markedly with td. Remarkably, the amount of AM forward masking decreased by only about 3 dB (a non-significant effect) when the masker m was decreased from 1 to 0.25. This result appears to be inconsistent with an explanation of AM forward masking in terms of adaptation in a MFB or in terms of a sliding temporal integrator.