Sinusoidal Tones Research Articles

Effects of frequency and level on auditory stream segregation.

This study examined the effect of center frequency and level on the perceptual grouping of rapid tone sequences. The sequence ABA-ABA-...was used, where A and B represent sinusoidal tone bursts (10-ms rise/fall, 80-ms steady state, 20-ms interval between tones) and - represents a silent interval of 120 ms. In experiment 1, tone A was fixed in frequency at 62, 125, 250, 500, 1000, 2000, 4000, 6000, or 8000 Hz. Both tones had a level of approximately 40 dB SL. Tone B started with a frequency well above that of tone A, and its frequency was swept toward that of tone A so that the frequency separation between them decreased in an exponential manner. Subjects were required to indicate when they could no longer hear the tones A and B as two separate streams, but heard only a single stream with a "gallop" rhythm. This changeover point between percepts is called the fission boundary. The separation between tones A and B at the fission boundary was roughly independent of the frequency of tone A when expressed as the difference in number of equivalent rectangular bandwidths (ERBs) between A and B, but varied more with frequency when the difference was expressed in barks or cents. In experiment 2, the center frequency was fixed at 250, 1000, or 4000 Hz, and the level of the A and B tones was 40, 55, 70, or 85 dB SPL. The frequency separation of the A and B tones at the fission boundary tended to increase slightly with increasing level, in a manner consistent with the broadening of the auditory filter with increasing level. The results support the "peripheral channeling" explanation of stream segregation advanced by Hartmann and Johnson [Music Percept. 9, 155-184 (1991)], and indicate that the perception of fusion or fission in alternating-tone sequences depends partly upon the degree of overlap of the excitation patterns evoked by the successive sounds in the cochlea, as assumed in the theory of Beauvois and Meddis [J. Acoust. Soc. Am. 99, 2270-2280 (1996)].

Temporal integration: reflections in the M100 of the auditory evoked field.

Previous work investigating temporal integration in the formation of the auditory evoked field component, M100, indicates an accumulation of stimulus attribute information in the processes underlying the M100 response with a temporal window for this integration of approximately 25-32 ms. We investigate the influence of stimulus duration on M100 amplitude using sinusoidal tone stimuli of increasing duration under two experimental conditions: constant intensity, and constant energy (with stimulus intensity decreasing as duration increased). We report that M100 amplitude increases with stimulus duration up to a point of saturation at approximately 40 ms; importantly, this dependence holds in both experimental conditions, despite differing stimulus intensities. Thus we conclude that (within this approximately 40 ms temporal window) stimulus duration itself, and not integrated energy, determines M100 amplitude.

Effects of spectral complexity and sound duration on automatic complex-sound pitch processing in humans – a mismatch negativity study

The pitch of a spectrally rich sound is known to be more easily perceived than that of a sinusoidal tone. The present study compared the importance of spectral complexity and sound duration in facilitated pitch discrimination. The mismatch negativity (MMN), which reflects automatic neural discrimination, was recorded to a 2.5% pitch change in pure tones with only one sinusoidal frequency component (500 Hz) and in spectrally rich tones with three (500–1500 Hz) and five (500–2500 Hz) harmonic partials. During the recordings, subjects concentrated on watching a silent movie. In separate blocks, stimuli were of 100 and 250 ms in duration. The MMN amplitude was enhanced with both spectrally rich sounds when compared with pure tones. The prolonged sound duration did not significantly enhance the MMN. This suggests that increased spectral rather than temporal information facilitates pitch processing of spectrally rich sounds.

Searching for an Explanation for Diphthong Perception: Dynamic Tones and Dynamic Spectral Profiles

The aim was to find a psychophysical explanation for the perception, by naive listeners, of diphthongs as single vowels, even though they are essentially formant movements. Subjects were asked to match sinusoidal tone and resonance glides around 1,000 Hz with two connected steady-state tones or resonances whose frequencies could be controlled independently. The expectation was that short glides (below 120 ms) would give rise to single perceptual events without any movement in a particular direction, so that the two matching steady-state patterns would not show any frequency direction either; long resonance glides (above 120 ms), on the other hand, were expected to be perceived as rising or falling and matched accordingly. The results showed an effect of duration, although it interacted with glide width. At durations shorter than about 120 ms, subjects placed the two steady profiles with which they had to match the dynamic profile closer together than with durations over 120 ms; however, this only occurred if a glide covered more than 500 Hz, and is therefore irrelevant to diphthong perception.

Harmonic partials facilitate pitch discrimination in humans: electrophysiological and behavioral evidence

The effect of the spectral tone structure on pre-attentive and attentive pitch discrimination was investigated. The mismatch negativity (MMN) component was recorded from reading subjects to pitch changes of identical magnitude in pure tones with only one sinusoidal frequency component and in spectrally rich tones with two additional harmonic partials. In a separate condition, subjects were asked to indicate detection of pitch change by a button press. The MMN was elicited with a larger amplitude and shorter latency by change in spectrally rich tones than by change in pure tones. Furthermore, the subjects’ behavioral responses were more accurate for spectrally rich tones than for sinusoidal tones. Together these data indicate that pre-attentive and attentive pitch discrimination is facilitated with spectrally rich sounds in comparison to pure sinusoidal tones.

Electromagnetic recordings reveal latency differences in speech and tone processing in humans

Human auditory electromagnetic brain responses to sinusoidal (tone) and speech stimuli (Finnish vowel /a/ with two different glottal excitations) were studied with whole-head magnetoencephalogram (MEG) and electrodes placed on the subject's scalp. The frequency and intensity of the sinusoidal stimulus were optimally adjusted to match the spectra of the speech stimuli. Both tone and speech sounds elicited a prominent electric N1–P2 and magnetic N1m–P2m response complex. N1 and P2 amplitudes were larger to speech sounds than those to the tone. This amplitude enhancement was not as evident in the N1m and P2m obtained in MEG. Both the N1(m) and P2(m) latency always peaked earlier for the tone than for the vowels. The source origin of N1m for both the tone and speech stimuli was in the auditory cortex, there being no significant location differences as a function of stimulus type. N1m in the right hemisphere was anterior to that on the left, and P2m was anterior to N1m in both hemispheres. Varying the perceptual quality of the vowels by changing their glottal excitations (from “soft” /a/ to “pressed” /A/) had no effect on the response amplitudes or latencies. Thus, the present results show that only the latency behavior of N1(m) and P2(m) reliably dissociates speech and tone processing in humans. The findings are discussed in relation to previous observations on cortical processing of sinusoidal and vowel sounds and with regard to the glottal excitation in speech processing.

An architecture for self-test of a wireless communication system using sampled IQ modulation and boundary scan

An architecture for system-level self-test of a wireless communication transceiver integrates the functional (parametric) self-test of the radio frequency subsystem, and the structural self-test of the digital subsystem. The digital subsystem is tested using extensions of the IEEE 1149.1 boundary scan standard to verify connections within circuit boards and between boards. The RF subsystem is tested using a loopback connection between the RF transmitter and receiver. An RF parametric self-test is performed using a digitally modulated signal (as opposed to a sinusoidal tone) as the test stimulus, and using samples from the receiver digitizer as test data. This loopback test scheme imposes a relatively small overhead on the RF system design.

New kids on the block: pancreatic stellate cells enter the fibrogenesis world

See article on page 534 Two recently published papers have shown that a cell type with morphological features of “vitamin A storing” stellate cells is present in rat and human...

Transcutaneous interruption of ultrasound contrast agents for blood flow evaluation.

The ability to create short boluses in targeted arteries with rapid rise times is limited by the transport of bubbles from the venous to arterial portion of the circulation. Acoustic interruption of contrast agent in arteries may create the short boluses necessary for simple wash-in/wash-out measures of blood flow. An ultrasound contrast agent was used with spectral Doppler ultrasound to observe contrast interruption in femoral arteries and VX2 carcinoma in a rabbit model. At an upstream location in the femoral artery, single, sinusoidal ultrasound tone bursts at 1.8 MHz with durations of 0.25 to 1 seconds were applied to interrupt the flow of contrast agent injected intravenously. In VX2 carcinoma, bursts as short as 40 cycles produced contrast interruption lasting only one cardiac cycle within the tumor periphery and I(SPPA) <3 W/cm2 produced measurable interruptions. Acoustic fields applied transcutaneously interrupted flow of contrast agents to form temporally short negative boluses.

A fuzzy system for tone detection applications

In this paper we propose a computationally simple algorithm for the detection of a sinusoidal tone for applications in the field of telecommunication systems. More specifically, we have developed an algorithm based on fuzzy logic (FL) to disable an echo canceller in a telephone exchange. The Fuzzy Tone Detector (FTD) presented uses three simple time-domain parameters and a matching phase based on only three fuzzy rules, trained by a new hybrid learning tool. A fuzzy system called a Fuzzy Phase Reversal Detector (FPRD) was also trained for the detection of phase reversals. The new algorithm outperforms the traditional methods in terms of robustness to channel noise, working up to a signal to noise ratio (SNR) of 0 dB.

Cochlear tuning in the gerbil: a comparison of responses to sinusoidal amplitude modulation and difference tone stimuli.

Vocalizations often have periodic variations of their acoustic waveform envelope. Two simultaneously presented frequencies have an envelope fluctuation with a frequency equal to their difference tone (DT = F2-F1). Sinusoidal amplitude modulation (SAM) of a carrier frequency also produces an envelope fluctuation. Electrical ensemble responses to DT and SAM stimuli were recorded from the gerbil's round window. The predominant frequency of the response to the DT stimuli is F2-F1; to the SAM stimuli, it is the modulation frequency. Both responses are spectrally, temporally, and dynamically non-linear. Forward masking of a low-frequency DT response produced a tuning curve (TC) with a tip at the high-stimulus frequency. Forward masker TCs of a low-frequency SAM ensemble response had tips at the high frequency of the carrier. Tip thresholds and sharpness of tuning of DT and SAM TCs are quite similar, with cochlear neurons having high characteristic frequencies providing sharply tuned information about low frequency acoustic envelope periodicities.

The perception of frequency peaks and troughs in wide frequency modulations. IV. Effects of modulation waveform.

This work extends previous studies on the perceptual asymmetry between the local maxima and minima of wide frequency modulations (FMs) [L. Demany and K. I. McAnally, J. Acoust. Soc. Am. 96, 706-715 (1994); L. Demany and S. Clément, J. Acoust. Soc. Am. 97, 2454-2459 (1995); L. Demany and S. Clément, J. Acoust. Soc. Am. 98, 2515-2523 (1995)]. In experiment 1, subjects had to discriminate frequency shifts in the temporally central vertex of V- and A-shaped FMs imposed on 200-ms sinusoidal tone bursts. The precise shapes of these FMs varied in eight steps from quasi-triangles (with a durationless central vertex) to quasi-squares (with a long-duration central vertex). The central vertex was either a minimum or a maximum, but in each case the corresponding frequency was near 1000 Hz and the FM span was about 0.5 oct. For each FM shape, the discrimination threshold was lower when the vertex was a maximum than when it was a minimum, but (in four subjects out of five) this difference decreased monotonically as the FM became less and less triangular. FM shape had a remarkably small effect on the discrimination of the maxima, and the thresholds measured for the sharpest maxima were unexpectedly low. In subsequent experiments, subjects had to discriminate frequency shifts in the starting point or the final point of unidirectional FMs (tone glides) that spanned about 0.5 oct in 100 ms. The relevant frequency extremum was near 1000 Hz in each condition. At the final point of the glides, discrimination was better for rising glides than for falling glides. At the starting point of the glides, discrimination was better for falling glides than for rising glides. Thus discrimination was always better when the relevant frequency extremum was a maximum than when it was a minimum, and this effect was produced both "forward" and "backward." The latter fact suggests that the perceptual asymmetry of FM originates at least partly from central factors.

The effects of nonconcurrent tonal and noise distractors upon auditory spatial resolution: The temporal, spatial, and spectral parameters underlying the ‘‘disruption effect.’’

The minimum audible angle (MAA) thresholds obtained by Mills [A. W. Mills, J. Acoust. Soc. Am. 30, 237–246 (1958)] involved two 1000-ms sinusoidal tone pulses presented sequentially with an interstimulus interval (ISI) of 1000 ms. In contrast to the generally good localization performance obtained by Mills, localization of two simultaneous events (concurrent localization or CMAA) results in relatively poor performance [D. R. Perrott, J. Acoust. Soc. Am. 76, 1704–1712 (1984)]. The current set of experiments attempts to bridge the gap between these two extreme paradigms. While the target tones (14-ms, 1000-Hz sinusoids) were presented sequentially (an MAA task), an attempt was made to systematically examine the consequences of the addition of a nonoverlapping, auditory event (tones or noise) during the interval between the target events. The results of this work indicate that localization performance is extremely sensitive to events that occur between the target events. The disruptive effect of a ‘‘nontarget’’ event during the ISI could even be observed when relatively long ISIs (814-ms) and very brief (14-ms) distractors events were used. Interesting interactions were encountered as a function of the spatial positioning of the nontarget (‘‘distractor’’) event. Implications of these results will be discussed.

Time dependent perturbation theory and tones in cascaded erbium-doped fiber amplifier systems

The time dependent perturbation theory of the gain dynamics of erbium-doped fiber amplifiers (EDFAs) is presented in this paper. The perturbed output is expressed explicitly in terms of the input perturbation. The general theory is then applied to sinusoidal tones; the results agree well with the experiment.

Matching frequency glides with two steady tones

Subjects were asked to match sinusoidal tone glides, of various durations (30–210 ms) and sweep widths (50–600 Hz) around a center frequency of 1000 Hz, with two connected steady-state tones whose frequencies could be controlled independently. The expectation was that short glides would give rise to single perceptual events without any movement in a particular direction, so that the two matching steady-state tones would not show any frequency direction either; long glides, on the other hand, were expected to be perceived as rising or falling tones and matched accordingly. It was hoped that this would provide a basis for an explanation of diphthongs as unitary percepts. However, no effect of duration was found at all; on average, glides were matched with tones whose frequencies corresponded to those reached by the glides after one-third and two-thirds of their course had been completed, regardless of duration.

Toxic waste or hormone? Carbon monoxide as a regulator of sinusoidal tone.

HepatologyVolume 24, Issue 5 p. 1319-1321 Hepatology ElsewhereFree Access Toxic waste or hormone? Carbon monoxide as a regulator of sinusoidal tone R A Weisiger, R A WeisigerSearch for more papers by this authorD C Rockey, D C RockeySearch for more papers by this author R A Weisiger, R A WeisigerSearch for more papers by this authorD C Rockey, D C RockeySearch for more papers by this author First published: November 1996 https://doi.org/10.1002/hep.510240555AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume24, Issue5November 1996Pages 1319-1321 ReferencesRelatedInformation

Toxic waste or hormone? Carbon monoxide as a regulator of sinusoidal tone

Toxic waste or hormone? Carbon monoxide as a regulator of sinusoidal tone

Broadband acoustic imaging of complex shaped targets

In some recent experiments conducted at the ARL:UT Lake Travis Testing Facility, acoustic images were created from scattering data of targets with complex geometries. The acoustic measurements were made in the volume in a monostatic scattering configuration at an approximate range of 40 m. The targets were constructed of either fiber-reinforced plastics and/or metals. A variety of large and small bandwidth product waveforms were chosen for the experiments including LFMs, simulated dolphin clicks, and short sinusoidal tone bursts. The frequencies of the waveforms span the range from 15 to 160 kHz. Data were taken by rotating the targets through 360 deg in finely spaced increments about several prechosen axes. The scattering data are processed in several ways. The processed data from different aspects are combined to reconstruct the shape of the object using image processing algorithms based on synthetic aperture and tomographic techniques. By varying the parameters of the incident waveforms, the resulting quality of the acoustic images is examined as a function of frequency and bandwidth. [Work supported by ONR.]

Processing of modulation frequency in the dorsal cochlear nucleus of the guinea pig: sinusoidal frequency-modulated tones

Frequency- and amplitude-modulated (FM and AM. respectively) tones are important information-bearing elements in voice sounds and can also be produced by the spatial movement of sound sources. Zhao and Liang (1995) recently reported the response features of dorsal cochlear nucleus (DCN) neurons to AM tones. In the present study, the responses of the guinea pig DCN neurons to sinusoidal FM (SFM) tones were examined. Discharges of the DCN units to the SFM tones phase-locked to the stimulus modulation frequencies ( f m). The phase-locked discharge patterns existed over broad ranges of modulation parameters and at stimulus levels as high as 95 dB SPL or modulation depths ( d m) as low as 2%. Robust phase-locking to the f m was observed in samples of all DCN unit types studied. The means of best f m ( Bf m and upper limit f m ( ULf m) of all recorded units were 510 Hz and 940 Hz, respectively. Pauser/Buildup (P/B) units had mean maximum synchronization index ( SI max) of 0.57. ON units had the highest Bf m with the mean of 646 Hz and subtype ON-S showed the highest mean of Sl max at 0.63. Phase-locking to the ƒ m was independent of discharge rates and existed even when th discharge rates were reduced to the background spontaneous rate (SR). A few units showed stronger synchronous responses to the square and triangular FM stimuli instead of the SFM tones. The relationship between the modulated responses and the unit's response area were further examined. The f, phase-locking occurred to modulation bands (or frequency ranges) within the response area, with the modulation bands as narrow as ± 160 Hz in the central inhibitory areas of the type IV units. As the width of the modulation band changed within a unit's response area, the phases of the f m, phase-locked responses of P/B units linearly changed while for Onset units, the change was lesser. The P/B and Onset units had a π phase shift and a π/2 phase change, respectively, as carrier frequencies ( f cs) passed through characteristic frequencies (CF) and the excitatory/inhibitory response boundaries. The phase-locked responses to the f ms were dependent on the SR but were independent of the CF. Low-SR ( > 2 spikes/s) units had higher synchronization of responses to the f m, than the high-SR ( > 2 spikes/s) units ( SI max = 0.64 and 0.42, respectively). These results suggest that the temporal characteristics of the fm is effectively represented in the responses of DCN units to the SFM tones. Such temporal encoding behavior can play an important role in the processing of the complex sounds in the auditory system. These results also have implications for a possible role for the DCN is in identifying the spatial movement of a sound source.

The probe-signal method and auditory-filter shape: Results from normal- and hearing-impaired subjects

In the probe-signal method, subjects are required to detect a signal in noise that is presented on the majority of trials at an "expected" (target) frequency but on a minority of trials at an "unexpected" probe frequency. Detection of the probes worsens with increasing separation between the target and probe frequencies. This result has often been interpreted as indicating that subjects monitor the output of a single auditory filter centered at the target frequency. To test this idea, a two-stage experiment was conducted. In the first stage, auditory-filter shapes were estimated using the notched-noise method at center frequencies of 1000, 1259, 1585, and 2000 Hz. These were the frequencies that were used for the targets in the second stage of the experiment. In the second stage, low-pass filtered white noise was presented continuously. On each trial, a cue tone was presented at one of the four possible target frequencies. The specific frequency was selected randomly on each trial. This was followed by two observation intervals during one of which a further sinusoidal tone was presented. This tone was either a target (the same as the cue frequency) (on 60% of trials), or had one of four possible probe frequencies corresponding to that target. The four probe frequencies were chosen to correspond to specific points on the estimated response curve of the auditory filter centered at the target frequency. The percentage of correct detections of a given probe was compared with that obtained in a separate condition where the frequency of the tone was fixed throughout, the cue frequency always equaled the target frequency, and the target was attenuated by an amount corresponding to the attenuation of the auditory filter at the probe frequency. Two subjects with normal hearing and two subjects with unilateral cochlear hearing loss were used. Comparison of the results for the normal and impaired ears suggests that the detectability of the probes is governed more by the selectivity of the auditory filters than by the ratios of the expected and probe frequencies. However, detection of the probes was generally better than would occur if subjects monitored the output of a single auditory filter centered at the target frequency.