共查询到20条相似文献,搜索用时 15 毫秒
1.
A Faulkner 《The Journal of the Acoustical Society of America》1985,78(6):1993-2004
Two models for pitch discrimination of harmonic complex sounds are discussed, a multiple-band probability summation model using comparisons among component frequencies, and a model in which residue pitches are compared. The second model is based on Goldstein's optimum-processor pitch theory [J. Acoust. Soc. Am. 54, 1496-1516 (1973)], and is distinguished from the multiple-band model by an internal noise process. Pitch difference limens from 2I2AFC tasks show that when the test signals comprise corresponding harmonics, relative pitch difference limens are less than the smaller relative difference limens for the component frequencies, which is consistent with the multiple-band model. The absence of corresponding harmonics significantly reduces relative pitch discriminability; this effect supports the model on Goldstein's theory. It appears that residue pitch comparisons are not used for pitch discrimination between sounds with corresponding components; rather, comparisons based on residue pitch are only employed where there are no common resolved components in the signals to be discriminated. 相似文献
2.
Reports using a variety of psychophysical tasks indicate that pitch perception by hearing-impaired listeners may be abnormal, contributing to difficulties in understanding speech and enjoying music. Pitches of complex sounds may be weaker and more indistinct in the presence of cochlear damage, especially when frequency regions are affected that form the strongest basis for pitch perception in normal-hearing listeners. In this study, the strength of the complex pitch generated by iterated rippled noise was assessed in normal-hearing and hearing-impaired listeners. Pitch strength was measured for broadband noises with spectral ripples generated by iteratively delaying a copy of a given noise and adding it back into the original. Octave-band-pass versions of these noises also were evaluated to assess frequency dominance regions for rippled-noise pitch. Hearing-impaired listeners demonstrated consistently weaker pitches in response to the rippled noises relative to pitch strength in normal-hearing listeners. However, in most cases, the frequency regions of pitch dominance, i.e., strongest pitch, were similar to those observed in normal-hearing listeners. Except where there exists a substantial sensitivity loss, contributions from normal pitch dominance regions associated with the strongest pitches may not be directly related to impaired spectral processing. It is suggested that the reduced strength of rippled-noise pitch in listeners with hearing loss results from impaired frequency resolution and possibly an associated deficit in temporal processing. 相似文献
3.
Gockel H Carlyon RP Moore BC 《The Journal of the Acoustical Society of America》2005,117(6):3860-3866
Gockel, Carlyon, and Plack [J. Acoust. Soc. Am. 116, 1092-1104 (2004)] showed that discrimination of the fundamental frequency (F0) of a target tone containing only unresolved harmonics was impaired when an interfering complex tone with fixed F0 was added to the target, but filtered into a lower frequency region. This pitch discrimination interference (PDI) was greater when the interferer contained resolved harmonics than when it contained only unresolved harmonics. Here, it is examined whether this occurred because, when the interferer contained unresolved harmonics, "pitch pulse asynchrony (PPA)" between the target and interferer provided a cue that enhanced performance; this was possible in the earlier experiment because both target and interferer had components added in sine phase. In experiment 1, it was shown that subjects were moderately sensitive to the direction of PPA across frequency regions. In experiments 2 and 3, PPA cues were eliminated by adding the components of the target only, or of both target and interferer, in random phase. For both experiments, an interferer containing resolved harmonics produced more PDI than an interferer containing unresolved harmonics. These results show that PDI is smaller for an interferer with unresolved harmonics even when cues related to PPA are eliminated. 相似文献
4.
Towards a model for discrimination of broadband signals 总被引:2,自引:0,他引:2
The conventional model for broadband discrimination assumes that resolution is limited by peripheral internal noise that is statistically independent across channels. In this paper, we extend this model in a number of directions. In particular, we compute, compare, and discuss the effects of interchannel correlation and central noise on the sensitivity index d', for discrimination of overall level and discrimination of spectral shape. 相似文献
5.
One reason for the poor pitch performance in current cochlear-implant users may be the highly synchronized neural firing in electric hearing that lacks stochastic properties of neural firing in normal acoustic hearing. This study used three different electric stimulation patterns, jittered, probabilistic, and auditory-model-generated pulses, to mimic some aspects of the normal neural firing pattern in acoustic hearing. Pitch discrimination was measured at standard frequencies of 100, 250, 500, and 1000 Hz on three Nucleus-24 cochlear-implant users. To test the utility of the autocorrelation pitch perception model in electric hearing, one, two, and four electrodes were stimulated independently with the same patterned electric stimulation. Results showed no improvement in performance with any experimental pattern compared to the fixed-rate control. Pitch discrimination was actually worsened with the jittered pattern at low frequencies (125 and 250 Hz) than that of the control, suggesting that externally introduced stochastic properties do not improve pitch perception in electric stimulation. The multiple-electrode stimulation did not improve performance but did not degrade performance either. The present results suggest that both "the right time and the right place" may be needed to restore normal pitch perception in cochlear-implant users. 相似文献
6.
J Wang T Baer BR Glasberg MA Stone D Ye BC Moore 《The Journal of the Acoustical Society of America》2012,132(1):339-356
Fundamental frequency difference limens (F0DLs) were measured for a target harmonic complex tone with nominal fundamental frequency (F0) of 200 Hz, in the presence and absence of a harmonic masker with overlapping spectrum. The F0 of the masker was 0, ± 3, or ± 6 semitones relative to 200 Hz. The stimuli were bandpass filtered into three regions: 0-1000 Hz (low, L), 1600-2400 Hz (medium, M), and 2800-3600 Hz (high, H), and a background noise was used to mask combination tones and to limit the audibility of components falling on the filter skirts. The components of the target or masker started either in cosine or random phase. Generally, the effect of F0 difference between target and masker was small. For the target alone, F0DLs were larger for random than cosine phase for region H. For the target plus masker, F0DLs were larger when the target had random phase than cosine phase for regions M and H. F0DLs increased with increasing center frequency of the bandpass filter. Modeling using excitation patterns and "summary autocorrelation" and "stabilized auditory image" models suggested that use of temporal fine structure information can account for the small F0DLs obtained when harmonics are barely, if at all, resolved. 相似文献
7.
Ultrasound Doppler methods are widely used in clinical practice as prospective investigational tool to study the vascular system and soft biological tissues. Meanwhile, the most general relationship between the power Doppler spectra, spectral characteristics of the scattering fluctuations and the probing ultrasound field parameters for some clinical implementations are still unexplored. Based upon the continuum model of scattering inhomogeneities, a set of the closed-form expressions for the correlation functions and the spectra of Doppler response of soft tissues and blood have been derived. The influence of the correlation among inhomogeneities and the diffusion processes on the Doppler power spectra formed by stationary flows have been examined. Computer simulations of Doppler spectra were performed for different values of correlation radius and diffusion coefficient. With simulation results the effects of the correlation among inhomogeneities and the diffusion processes on the spectral width and mean frequency are established and discussed in respect to turbulent flows. Closed-form expressions for correlation functions and Doppler spectra for the vibrational sonoelastography technique for visualizing malignant tumors in tissues have been derived. Based on the peculiarities of the obtained Doppler spectra, it is shown that the differentiation of soft tissues with respect to the amplitude value of constrained oscillations is feasible. The expressions were derived for the cases of non-stationary accelerated blood movement. It has been found that the frequency dependence reveals solely at a finite time of observation and depends on the initial phase of the accelerated movement. 相似文献
8.
This study evaluated the reliability of pitch judgments as a basic step toward increasing interrater and intrarater reliability of multidimensional perceptual judgments of the speaking voice. Forty-five undergraduate university students studying speech/language pathology made piano-to-piano tone pitch matches and vowel-to-piano pitch matches using a computer software program. The mean percentage correct of piano-to-piano tone matches was 91.3% and of vowel-to-piano matches was 75.6%. Subjects who scored 100% correct were significantly faster at the pitch matching task. Further research of perceptual judgments of pitch and its contribution to multidimensional rating tasks is warranted. 相似文献
9.
The problem of resolving a weak broadband signal against the background of a strong broadband signal using adaptive superresolution algorithms for signals with distorted coherence is considered. The correlation matrix is estimated using not only time but also frequency accumulation with a differently formed focusing matrix. Imitative simulation has been carried out and the simulation results are analyzed. 相似文献
10.
11.
Cochlear implant users may perceive intermediate place-pitches between those elicited by the individual electrodes when two electrodes are stimulated simultaneously or sequentially. This study examined pitch discrimination between adjacent electrodes using sequential dual-electrode stimulation in terms of the sensitivity index, d', which was obtained by adding d's from intermediate dual-electrode stimuli. Loudness was balanced for each tested pair and the intensities were roved. Twelve ears with the Nucleus 24 or Freedom implants demonstrated a wide range of d', from 0.7 to 9.6. "Virtual channels" can be implemented through nonsimultaneous stimulation, with comparable pitch discrimination to that observed with simultaneous stimulation. 相似文献
12.
Watkinson RK Plack CJ Fantini DA 《The Journal of the Acoustical Society of America》2005,118(2):934-945
Complex tone bursts were bandpass filtered, 22nd-30th harmonic, to produce waveforms with five regularly occurring envelope peaks ("pitch pulses") that evoked pitches associated with their repetition period. Two such tone bursts were presented sequentially and separated by an interpulse interval (IPI). When the IPI was varied, the pitch of the whole sequence was shifted by between +2% and -5%. When the IPI was greater than one period, little effect was seen. This is consistent with a pitch mechanism employing a long integration time for continuous stimuli that resets in response to temporal discontinuities of greater than about one period of the waveform. Similar pitch shifts were observed for fundamental frequencies from 100 to 250 Hz. The pitch shifts depended on the IPI duration relative to the period of the complex, not on the absolute IPI duration. The pitch shifts are inconsistent with the autocorrelation model of Meddis and O'Mard [J. Acoust. Soc. Am. 102, 1811-1820 (1997)], although a modified version of the weighted mean-interval model of Carlyon et al. [J. Acoust. Soc. Am. 112, 621-633 (2002)] was successful. The pitch shifts suggest that, when two pulses occur close together, one of the pulses is ignored on a probabilistic basis. 相似文献
13.
Modulation detection thresholds (as a function of sinusoidal amplitude modulation frequency) and temporal gap detection thresholds were measured for three low-pass-filtered noise signals (fc = 1000, 2000, and 4000 Hz), a high-pass-filtered noise signal (fc = 4000 Hz), and a broadband signal. The two latter noise signals were effectively low-pass filtered (fc = 6500 Hz) by the earphone. Each of the filtered signals was presented with a complementary filtered noise masker. Modulation and gap detection thresholds were lowest for the broadband and high-pass signals. Thresholds were significantly higher for the low-pass signals than for the broadband and high-pass signals. For these tasks and conditions, the high-frequency content of the noise signal was more important than was the signal bandwidth. Sensitivity (s) and time constant (tau) indices were derived from functions fitted to the modulation detection data. These indices were compared with gap detection thresholds for corresponding signals. The gap detection thresholds were correlated inversely (rho = -1.0, p less than 0.05) with s (i.e., smaller gap detection thresholds were correlated with greater sensitivity to modulation), but were not correlated significantly with tau, which was relatively invariant across signal conditions. 相似文献
14.
Raymond H. Colton 《Journal of voice》1987,1(3)
Pitch is an important attribute of a musical sound. With it the melody of a song is established. With it the beauty of a voice is showcased. But how does pitch affect the perception of voice? Is it used to help to distinguish among voices or does it merely exist in the background, affecting the fine details of a voice but not radically altering the voice? The purpose of this paper is to review some of the evidence on the role of pitch in the perception of voice quality; specifically for the discrimination of one voice quality from another. The objective of the discussion is to understand how pitch affects our perception of voice quality and its importance to the perception of musical sound. 相似文献
15.
J W Horst 《The Journal of the Acoustical Society of America》1989,85(5):2022-2030
Detection and discrimination of frequency modulation were studied for harmonic signals with triangular spectral envelopes. The center frequency of the stimuli was near 2 kHz; the fundamental frequency was near 100 Hz. To prevent the possibility that the discrimination was based on differences of initial or final frequencies, these frequencies were equal within and across modulations in each individual experiment. Differences between modulations consisted of differences in the trajectories between the initial and final frequencies. Performance worsened as the slopes of the spectral envelopes decreased. Addition of noise also impaired modulation discrimination. The dependence on the signal-to-noise ratio was similar to what is found for stationary stimuli: Discrimination of frequency modulation deteriorated more rapidly with decreasing signal-to-noise ratio when stimuli had shallow spectral slopes than when they had steep spectral slopes. In spite of the precautions taken (i.e., initial and final frequency the same), the discrimination of these stimuli was more likely based on quasistationary frequency discrimination than on discrimination of modulation rate. This conclusion is consistent with previous findings for pure tones presented in quiet that frequency discrimination is more acute than modulation-rate discrimination. 相似文献
16.
17.
《声学学报:英文版》2012,(4):474-481
The main goal of this study was to systematically investigate the relative contribution of spectral resolution and temporal envelope periodicity to musical pitch discrimination. Stimuli from four instruments(clarinet,trumpet,piano and violin) and synthetic complex tone were utilized.A noise-excited vocoder was used to control the spectral resolution and temporal envelope periodicity of the musical stimuli.Ten normal-hearing subjects were recruited for the study.Psychoacoustic experiments on pitch discrimination were carried out.Results showed that the spectral cue was important for musical pitch discrimination.Relative good performance could be achieved when there were 16 frequency channels.No clear effect was found for the temporal envelope periodicity to pitch discrimination. 相似文献
18.
19.