Fundamental Frequency Variation Research Articles

Resonant Frequency Deviation Analysis and Modified Notch Filter-Based Active Damping for SiC-Based PMSM Drive With Sine Wave Filter

In the permanent-magnet synchronous machine (PMSM) drive system, the adoption of silicon carbide (SiC) devices brings up new challenges, such as overvoltage, electromagnetic interference emission, and bearing current. To surmount these barriers, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter designed as the sine wave filter can be introduced into the machine drive system. However, filter and stator inductance can create unwanted electrical resonance issues. For the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> -equipped PMSM drive system, there are two main factors that cause the drift of resonant frequency and change of stable region: (1) synchronous coordinate transformation with variable fundamental frequency, (2) parameter variations due to the magnetic saturation effect. In this paper, the deviation of resonant frequency caused by coordinate transformation is discussed. Then, the inherent damping effects and stability range in the rotating reference frame are derived in detail. Furthermore, considering the parameter mismatch disturbances, an active damping method based on the enhanced notch filter is presented, of which notch frequency is designed lag behind the nominal resonant frequency. The accurate discretization method and theoretical stability analysis in discrete <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> -domain are conducted. The experimental results are presented to verify the effectiveness and robustness of the proposed analysis and method.

Acoustic correlates of perceived anger in the Ferguson clear speech database

Previous work has shown that clear speech is perceived as sounding angry significantly more often than conversational speech (Morgan and Ferguson, 2017; Young, 2021). The current study examined possible acoustic correlates of perceived anger in clear speech. A principal component analysis was completed to guide selection of acoustic variables for analysis. The remaining six acoustic measures, fundamental frequency median, fundamental frequency variability, relative mid-frequency energy from 1000 to 3150 Hz, speaking rate, and degree of amplitude modulation at 2 Hz and 16Hz envelopes, were analyzed using mixed effects regression. Results indicated that after controlling for speaking style, fundamental frequency approached significance but did not significantly predict perceived anger. However, speaking rate significantly predicted perceived anger after controlling for speaking style, with slower rates leading to an increase in perceived anger. Further, there was a significant interaction between speaking rate and speaking style, where slower speech was only perceived as angry in the clear speech style. Finally, a decrease in the degree of low-frequency amplitude modulation (i.e., equal emphasis on both content and function words) led to an increase in perceived anger after controlling for speaking style. The results have implications for counseling individuals in the use of clear speech.

The Relationship Between Pitch Discrimination and Fundamental Frequency Variation: Effects of Singing Status and Vocal Hyperfunction

The purpose of this study was to investigate the relationship between pitch discrimination and fundamental frequency (fo) variation in running speech, with consideration of factors such as singing status and vocal hyperfunction (VH). Female speakers (18-69 years) with typical voices (26 non-singers; 27 singers) and speakers with VH (22 non-singers; 30 singers) completed a pitch discrimination task and read the Rainbow Passage. The pitch discrimination task was a two-alternative forced choice procedure, in which participants determined whether tokens were the same or different. Tokens were a prerecorded sustained /ɑ/ of the participant's own voice and a pitch-shifted version of their sustained /ɑ/, such that the difference in fo was adaptively modified. Pitch discrimination and Rainbow Passage fo variation were calculated for each participant and compared via Pearson's correlations for each group. A significant strong correlation was found between pitch discrimination and fo variation for non-singers with typical voices. No significant correlations were found for the other three groups, with notable restrictions in the ranges of discrimination for both singer-groups and in the range of fo variation values for non-singers with VH. Speakers with worse pitch discrimination may increase their fo variation to produce self-salient intonational changes, which is in contrast to previous findings from articulatory investigations. The erosion of this relationship in groups with singing training and/or with VH may be explained by the known influence of musical training on pitch discrimination or the biomechanical changes associated with VH restricting speakers' abilities to change their fo.

Intonation Parameters in Gender Diverse People

Although intonation is often addressed in speech training for gender diverse individuals, the relationship between intonation and femininity/masculinity ratings remains unclear. The aim of this study was to examine differences in intonation parameters in gender diverse individuals. Moreover, the relationship between acoustic intonation parameters and femininity/masculinity ratings was investigated. Speech samples of semistructured speech were elicited from cisgender (cis) (107 ciswomen, 104 cis men), transgender (trans) (19 trans women, 10 trans men), and non-binary (n=11) individuals using a prosody protocol. An objective acoustic analysis was performed to compare intonation parameters (upward/downward/flat intonation shift, general and final intonation shift, general fundamental frequency range, fundamental frequency variation index) between groups. In addition, a listening experiment was conducted, consisting of a cis and gender diverse listening panel (n=41). The listeners were asked to rate the femininity/masculinity of speech samples (n=57) using a visual analogue scale. Correlational analyses were used to examine the relationship between intonation parameters and femininity/masculinity ratings. Similarity was found in the intonation parameters of participants with a similar gender identity. In non-binary speakers, no significant differences in acoustic intonation parameters were found between these speakers and the cisgender speakers. In addition, no significant correlations were found between the acoustic intonation parameters and the femininity/masculinity ratings in the groups with cis men, cis women, and non-binary participants. However, moderate to strong significant correlations were found between acoustic intonation parameters and femininity/masculinity ratings in the trans participants. Intonation is a "speech marker" that distinguishes between groups with a different gender identity. No relationship was observed between intonation and femininity/masculinity ratings for cisgender and non-binary speakers. However, the significant relationship between these parameters for transgender participants (trans men and trans women) provides evidence for intonation exercises in gender affirming voice, speech, and communication training, and therefore contribute to evidence-based intonation training in transgender persons.

Recurrent Wavelet Fuzzy Neural Network-Based Reference Compensation Current Control Strategy for Shunt Active Power Filter

The usage of a shunt active power filter (SAPF) is one of the helpful means to mitigate the reactive power and harmonic current of a power grid. The compensation performance of the SAPF is related to the accuracy of the reference voltage extraction from the utility grid, the control stability of the DC-link voltage regulation, and the synchronization between the source voltage and the reference compensation current. To modify the performance of the SAPF for the harmonic compensation, the control strategy of the SAPF reference compensation current based on the recurrent wavelet fuzzy neural network (RWFNN) is proposed in this paper. There are three sections in the proposed control strategy, including the regulated fundamental positive-sequence extraction (section A), DC-link voltage regulation (section B), and calculation of reference compensation current (section C). By regulating the analysis mechanism with the variation of fundamental frequency in the section A, the accurate reference voltage would be obtained. The control stability for the regulation of the DC-link voltage can be accomplished by applying the RWFNN-based controller in the section B. With the synchronized reference voltage in the section A and the estimated control current in the section B, the reference compensation current can be correctly obtained in the section C. From the case studies with the real-time simulator produced by OPAL-RT Technologies Inc., the effectiveness of proposed control strategy for the SAPF reference compensation current can be verified.

Exploring the mechanics of fundamental frequency variation during phonation onset.

Fundamental frequency patterns during phonation onset have received renewed interest due to their promising application in objective classification of normal and pathological voices. However, the associated underlying mechanisms producing the wide array of patterns observed in different phonetic contexts are not yet fully understood. Herein, we employ theoretical and numerical analyses in an effort to elucidate the potential mechanisms driving opposing frequency patterns for initial/isolated vowels versus vowels preceded by voiceless consonants. Utilizing deterministic lumped-mass oscillator models of the vocal folds, we systematically explore the roles of collision and muscle activation in the dynamics of phonation onset. We find that an increasing trend in fundamental frequency, as observed for initial/isolated vowels, arises naturally through a progressive increase in system stiffness as collision intensifies as onset progresses, without the need for time-varying vocal fold tension or changes in aerodynamic loading. In contrast, reduction in cricothyroid muscle activation during onset is required to generate the decrease in fundamental frequency observed for vowels preceded by voiceless consonants. For such phonetic contexts, our analysis shows that the magnitude of reduction in the cricothyroid muscle activation and the activation level of the thyroarytenoid muscle are potential factors underlying observed differences in (relative) fundamental frequency between speakers with healthy and hyperfunctional voices. This work highlights the roles of sometimes competing laryngeal factors in producing the complex array of observed fundamental frequency patterns during phonation onset.

Prosodic features conveying doubt and trust

Research in affective prosody has shown that doubt (specifically, incredulity) is communicated through distinctive features like a slower speech rate, greater variability in fundamental frequency (F0), and a characteristic F0 pattern including an utterance final rise in F0. However, the opposite of doubt, trust (or belief), has not been examined as a prosodically distinct attitude. In response, this study explores the full range of doubt and trust native speakers of American English can express through prosody. In a web-based production experiment, we asked 30 participants to produce 12 utterances in neutral, trusting, and doubting prosody. A multinomial logistic regression analysis revealed that incredulous prosody differed significantly from neutral prosody primarily in its lower initial F0 and longer duration. Trust also differed from neutrality, with a significantly higher utterance initial F0 and less amplitude variability than was observed in neutral utterances. In a perception experiment, 115 participants listened to 36 tokens collected from the production experiment and were asked whether the talker expressed doubt or trust. Participants were generally accurate in their judgement of talker attitude, and acoustic variables of utterance-initial F0 and speech rate significantly predicted participant ratings of the talker's doubt or trust.

Bright Voice Quality and Fundamental Frequency Variation in Non-binary Speakers

1) To investigate if vocal variation produced by assigned-female-at-birth (AFAB) non-binary people differed from vocal variation produced by cisgender (cis) participants. Cue values produced by non-binary participants were predicted to differ from those values produced by cisgender participants. 2) To determine if previous subjective assessments of bright voice quality in AFAB non-binary participants were quantifiable, and if so, if non-binary and cisgender participants differed in their voice quality production. A quantitative comparative research design. Phonetic and statistical analyses of continuous speech samples produced by AFAB non-binary and cisgender participants. Vocal cues were mean fundamental frequency (F0) and bright voice quality, measured by cepstral peak prominence-smoothed and spectral slope, with speaker gender as the predictor. At the group level, non-binary participants produced intermediate F0 values - significantly lower than the cis women's and significantly higher than the cis men's. Individually, the majority of non-binary participants produced mean F0 in this intermediate range. Non-binary participants produced significantly less negative spectral slope and higher cepstral peak prominence-smoothed, indicative of a brighter, more resonant voice quality. Individual-level results indicated that vocal training and vocal tract physiology did not fully account for the results found. Participants' agency, particularly their motivation to alter vocal output to avoid being misgendered, has an effect on the AFAB non-binary participants' F0 production and potentially their voice quality. The majority of AFAB non-binary participants uniquely produced the cue combination of intermediate F0 and bright voice quality.

Long-term Average Spectrum and Nasal Accelerometry in Sentences of Differing Nasality and Forward-Focused Vowel Productions Under Altered Auditory Feedback

To investigate whether voice focus adjustments can alter the audio-vocal feedback and consequently modulate speech/voice motor control. Speaking with a forward-focused voice was expected to enhance audio-vocal feedback and thus decrease the variability of vocal fundamental frequency (F0). Twenty-two healthy, untrained adults (10 males and 12 females) were requested to sustain vowel /a/ with their natural focus and a forward focus and to naturally read the nasal, oral, and mixed oral-nasal sentences in normal noise-masked auditory conditions. Meanwhile, a miniature accelerometer was externally attached on the noise to detect the nasal vibrations during vocalization. Audio recordings were made and analyzed using the long-term average spectrum (LTAS) and power spectral analysis of F0. Compared with naturally-focused vowel production and oral sentences, forward-focused vowel productions and nasal sentences both showed significant increases in nasal accelerometric amplitude and the spectral power within the range of 200∼300 Hz, and significantly decreased the F0 variability below 3 Hz, which has been reported to be associated with enhanced auditory feedback in our previous research. The auditory masking not only significantly increased the low-frequency F0 variability, but also significantly decreased the ratio of the spectral power within 200∼300 Hz to the power within 300∼1000 Hz for the vowel and sentence productions. Gender differences were found in the correlations between the degree of nasal coupling and F0 stability as well as in the LTAS characteristics in response to noise. Variations in nasal-oral acoustic coupling not only change the formant features of speech signals, but involuntarily influence the auditory feedback control of vocal fold vibrations. Speakers tend to show improved F0 stability in response to a forward-focused voice adjustment.

Quality of Voice in Patients With Partial Deafness Before and After Cochlear Implantation

Quality of Voice in Patients With Partial Deafness Before and After Cochlear Implantation

A dynamic binaural harmonic-cancellation model to predict speech intelligibility against a harmonic masker varying in intonation, temporal envelope, and location

The aim of this study was to extend the harmonic-cancellation model proposed by Prud’homme et al. [J. Acoust. Soc. Am. 148 (2020) 3246-–3254] to predict speech intelligibility against a harmonic masker, so that it takes into account binaural hearing, amplitude modulations in the masker and variations in masker fundamental frequency (F0) over time. This was done by segmenting the masker signal into time frames and combining the previous long-term harmonic-cancellation model with the binaural model proposed by Vicente and Lavandier [Hear. Res. 390 (2020) 107937]. The new model was tested on the data from two experiments involving harmonic complex maskers that varied in spatial location, temporal envelope and F0 contour. The interactions between the associated effects were accounted for in the model by varying the time frame duration and excluding the binaural unmasking computation when harmonic cancellation is active. Across both experiments, the correlation between data and model predictions was over 0.96, and the mean and largest absolute prediction errors were lower than 0.6 and 1.5 dB, respectively.

Acoustic voice variation in spontaneous speech.

This study replicates and extends the recent findings of Lee, Keating, and Kreiman [J. Acoust. Soc. Am. 146(3), 1568-1579 (2019)] on acoustic voice variation in read speech, which showed remarkably similar acoustic voice spaces for groups of female and male talkers and the individual talkers within these groups. Principal component analysis was applied to acoustic indices of voice quality measured from phone conversations for 99/100 of the same talkers studied previously. The acoustic voice spaces derived from spontaneous speech are highly similar to those based on read speech, except that unlike read speech, variability in fundamental frequency accounted for significant acoustic variability. Implications of these findings for prototype models of speaker recognition and discrimination are considered.

The Effects of Intensive Voice Treatment in Mandarin Speakers With Parkinson's Disease: Acoustic and Perceptual Findings.

This study investigated the effects of intensive voice treatment on subjective and objective measures of speech production in Mandarin speakers with hypokinetic dysarthria. Nine Mandarin speakers with hypokinetic dysarthria due to Parkinson's disease received 4 weeks of intensive voice treatment (4 × 60 min per week). The speakers were recorded reading a passage before treatment (PRE), immediately after treatment (POST), and at 6-month follow-up (FU). Listeners (n = 15) rated relative ease of understanding (EOU) of paired speech samples on a visual analogue scale. Acoustic analyses were performed. Changes in EOU, vocal intensity, global and local fundamental frequency (f o) variation, speech rate, and acoustic vowel space area (VSA) were examined. Increases were found in EOU and vocal intensity from PRE to POST and from PRE to FU, with no change found from POST to FU. Speech rate increased from PRE to POST, with limited evidence of an increase from PRE to FU and no change from POST to FU. No changes in global or local f o variation or in VSA were found. Intensive voice treatment shows promise for improving speech production in Mandarin speakers with hypokinetic dysarthria. Vocal intensity, speech rate, and, crucially, intelligibility, may improve for up to 6 months posttreatment. In contrast, f o variation and VSA may not increase following the treatment. https://doi.org/10.23641/asha.19529017.

Usefulness of Water-Resistance Straw Phonation in Discrimination of Adductor-Type Spasmodic Dysphonia and Muscle Tension Dysphonia

Objectives: Although Adductor-type spasmodic dysphonia (AdSD) and Muscle tension dysphonia (MTD) show similar phonetic symptoms, the causes and treatment methods are different. Therefore, discrimination is necessary for the proper treatment of the two diseases. The purpose of this study is to investigate the usefulness of Water-resistance straw phonation (WSP) as a diagnostic therapy for the differentiation of AdSD and MTD. To that end, Both patients with AdSD and MTD performed WSP, and their voices was measured before and after diagnostic therapy.Methods: A total of 27 (18 MTD, 9 AdSD) individuals participated in this study. The MTD group (4 male, 14 female) mean age was 30.01 years and the AdSD (2 male, 7 female) group mean age was 31.03. Both groups were treated with diagnostic therapy using WSP which took approximately 90 seconds. The acoustic analysis and auditory–perceptual assessment were completed after diagnostic therapy.Results: The MTD group was significantly lower in Jitter Percent (Jitter) (p= .003), Pitch Perturbation Quotient (PPQ) (p= .007), Fundamental Frequency Variation (vF0) (p= .004), Shimmer Percent (Shimmer) (p= .010), Amplitude Perturbation Quotient (APQ) (p= .012), Peak to Peak Amplitude Variation (vAm) (p= .005) and auditory–perceptual grade (p= .007). However, the AdSD group was not significantly different for all variables after performing the WSP.Conclusion: WSP is one of the methods that relieve laryngeal hypertension. In this study, the voice improvement of the MTD group after diagnostic therapy using WSP meant that the laryngeal hypertension was relieved. This change indicates a high probability of MTD as opposed to AdSD. Whereas, no improvement or worsening of the voice problem suggests neither the probability of MTD nor no confirmation of AdSD. Therefore, a diagnostic therapy using WSP may be useful as one of the evaluation methods for discrimination between AdSD and MTD.

Age and Gender Differences in Belgian Dutch Intonation

This study investigated whether intonation is influenced by age and gender and obtained normative data for the intonation of Flemish (Belgian Dutch) speaking cis women and cis men in Flanders, Belgium, per age group. A total of 105 cis women and 102 cis men were included and equally spread in five age groups by gender. Semi-structured speech samples were elicited using a prosody protocol. An objective acoustic analysis was performed to determine four intonation parameters (general intonation shift, general fundamental frequency range, final intonation shift, and fundamental frequency variation index). Cis women used a higher percentage of general upward and downward intonation shifts than cis men. Cis men generally used more flat intonation shifts than cis women. A larger mean value was observed in cis women as compared to cis men for each of the continuous intonation parameters per sentence type. In terms of age, differences in continuous intonation parameters were found between younger and older age groups, mostly with the 46-55-year-old age group, in which the younger age groups showed smaller mean values for all parameters. Cis women use a more expressive intonation than cis men. In terms of age, older persons showed a more expressive intonation in a number of sentences compared to younger persons. The prosody protocol and the normative data from this study can be used to determine speech therapy goals.

Speed Control of Induction Motor Using Variable Frequency Driver (VFD) Method Based On Arduino Nano

This research aims to control the speed of an induction motor by exploiting changes in the fundamental frequency. The inverter as the main part of the variable frequency driver (VSD) uses the IRFZ44n Mosfet as a power switch with a full bridge topology to convert the DC source to AC power. Fundamental frequency manipulation takes place during the conversion process. The method used is to change the variable fundamental frequency of the SPWM signal generated by the Arduino nano to control the power switch. Experiments are carried out based on two stages, namely simulation, and experiment. The simulation is performed using the Pspice A/D Lite software to take time sample data (HIGH and LOW) at each frequency change of 13Hz, 25Hz, 38Hz, and 50Hz, then the sample data is input on the Arduino nano as an SPWM signal generator to control the power switch. The results of the variable frequency drive test are the frequencies generated to drive the induction motor at 12.50 Hz, 24.04 Hz, 35.71 Hz, and 48.54 Hz at motor speeds from 227.7 to 1359.6 rpm.

Voice modulatory cues to structure across languages and species.

Voice modulatory cues such as variations in fundamental frequency, duration and pauses are key factors for structuring vocal signals in human speech and vocal communication in other tetrapods. Voice modulation physiology is highly similar in humans and other tetrapods due to shared ancestry and shared functional pressures for efficient communication. This has led to similarly structured vocalizations across humans and other tetrapods. Nonetheless, in their details, structural characteristics may vary across species and languages. Because data concerning voice modulation in non-human tetrapod vocal production and especially perception are relatively scarce compared to human vocal production and perception, this review focuses on voice modulatory cues used for speech segmentation across human languages, highlighting comparative data where available. Cues that are used similarly across many languages may help indicate which cues may result from physiological or basic cognitive constraints, and which cues may be employed more flexibly and are shaped by cultural evolution. This suggests promising candidates for future investigation of cues to structure in non-human tetrapod vocalizations.This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part I)’.

Effects of dynamic pitch manipulation methods on speech perception in noise by older listeners with hearing loss

Dynamic pitch, as defined by the variation in fundamental frequency (f0) of speech, is a major acoustic cue in speech perception. While dynamic pitch manipulation negatively affects speech perception in noise on a group level, there is substantial variability across older listeners with hearing loss. The manipulation method used in previous studies, however, may distort pitch contours in natural speech. In this study, a new manipulation method is employed by exaggerating pitch contours above mean pitch. The primary purpose of the study is to compare the effects of these two manipulation methods on speech recognition in noise by older listeners with hearing loss. The secondary purpose is to examine the connection between individuals’ responses to dynamic pitch manipulation and intonation perception. Speech reception threshold in noise was measured from 8 older listeners (mean age 74.5 years) with mild-moderate sensorineural hearing loss. Intonation perception was measured by a 2-alternative discrimination paradigm. Data up to date suggest a stronger effect from the new method, with the weakened dynamic pitch being more beneficial than the original pitch contour. Further, individuals’ intonation perception is associated with their response to pitch manipulation. The theoretical and clinical implications will be discussed. [Word supported by NIH.]

How intonation and articulation cues impact gender perception for cisgender and transgender speakers

Gender identities beyond cisgender male and female are poorly represented in speaker gender perception research. Incorporating transgender speakers may reveal speech characteristics that extend beyond hetero-cis-normative standards and better reflect listeners' real-world experiences and cognitive representations of gender. This study compared how intonation and articulation impact listeners’ judgements of speaker gender identity and masculinity/femininity using cisgender male and female, transfeminine, and transmasculine speakers. Cisgender speakers' fundamental and formant frequencies were shifted to gender-ambiguous range and transfeminine and transmasculine speakers to prototypically cisgender female or male range, respectively. Listeners judged speaker gender in conditions that either removed fundamental frequency variation, frequencies above 500 Hz, or both cues. There were nonuniform effects of intonation and articulatory modifications on listener perceptions of gender across speaker groups. However, articulation influenced listener perception more than intonation. When listeners heard articulatory as compared to intonation cues, gender identification scores were generally higher for all speaker groups and masculinity/femininity scores more aligned with cisgender female and transfeminine speakers’ gender identities. Although most prior work with transgender speakers has focused on intonation, articulation can substantially impact gender perception and should be considered in gender affirming communication training.

Low-Profile Harmonic Transponder for IoT Applications

This paper proposes a novel single-layer, low-profile harmonic transponder to be integrated with the printable diodes based on Si particles. The introduced prototype consists of two bowtie dipoles that are directly matched to the harmonic generation element at a fundamental 2.45GHz frequency and also at the corresponding second harmonic 4.9GHz frequency. Therefore, the antennas and T-matching parts can be manufactured as separate inlays using a single layer-substrate. Besides the new prototype, the harmonic conversion loss (CL) is theoretically and experimentally investigated. In this regard, the equivalent circuit is driven and utilized to analyze the CL performance with variations in fundamental frequency and input power. The introduced transponder outperforms the state-of-the-art work from the printability, size, and CL point of views.