• The Journal of the Acoustical Society of Korea
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• v.19 no.5
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• pp.60-64
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• 2000

This paper studies the relation between the Fundamental Frequency (F0) and the formants of simple vowels in the Korean language sung by sopranos. It is hewn that, in soprano singing, the F0 of a vowel affects its formants. For this reason the formants of simple vowels sung by sopranos must be considered in all over the soprano singing range. We recorded the five simple vowel sounds /a/, /e/, /i/, /o/, and /u/ sung by five professional sopranos from A3 (220.0Hz) to A5 (880.0Hz) in the major scale and compared the formants of the sung vowels with those of spoken vowels. We observed that F1 and F2 of sung vowels were stable in low F0 (lower than B4) but in high F0 (higher than B4), F1 and F2 lost their stabilities. In the case of /a/, /o/, and /u/, the slope of the F1-F2 graph was about 2.6, and those of the F0-F2 and F0-Fl graphs were 2.2-2.5 and 0.7-1.0, respectively. And as the F0 increases, the F1 and F2 of sung vowels /a/, /e/, /i/, /o/, and /u/ were almost the same. At A5, the Fl and F2 of five sung vowels had the same values. This results suggest that the relation between the F0 and the formants be used to synthesize soprano's singing vowels.

• Phonetics and Speech Sciences
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• v.1 no.4
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• pp.187-193
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• 2009

For this study, the external laryngeal lengths of 9 females and 9 males with normal voices were measured together with their ages, heights, and weights, and after they read aloud sentences for 3 minutes, their habitual speaking fundamental frequencies, speaking low pitches, speaking high pitches, and vocal fold closed quotients were measured. The Spearman rank correlation analysis on these data showed a significant negative correlation between the external laryngeal length and the habitual speaking fundamental frequency for both females and males, a significant negative correlation between the external laryngeal length and the speaking high pitch for only males, a significant negative correlation between the external laryngeal length and the speaking low pitch for both females and males, and a significant positive correlation between the external laryngeal length and the vocal fold closed quotient for only males.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.3
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• pp.423-431
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• 2002

An experimental study is conducted to investigate the effect of two-frequency forcing on turbulent flow behind a backward-facing step at the Reynolds number of 27000 based on the step height. The forcing is provided from a thin slit located at the edge of the backward-facing step to increase mixing behind the backward-facing step and consequently to reduce the reattachment length. With single frequency forcing, the minimum reattachment length is obtained at the non-dimensional forcing frequency (F) of St$\_$h/ = 0.29. With two-frequency forcing, a subharmonic frequency (F/2) or biharmonic frequency (2F) is combined with the fundamental frequency (F), i.e. (F, F/2) or (F, 2F) forcing is applied. In the case of (F, F/2) forcing, the reattachment length is not much sensitive to the phase difference between F and F/2. However, the reattachment length significantly depends on the phase difference between F and 2F in the case of (F, 2F) forcing. At a certain range of the phase difference, the reattachment length becomes smaller than that of the single frequency forcing.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.468-474
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• 2010

In this paper, a VCHO(Voltage Controlled Harmonic Oscillator) for K-band application has been designed and implemented. The proposed oscillator has a structure of two hair-pin resonators placed on input and output of active device. Using in/out common frequency tuning structure, the VCHO yields some advantages of the enhanced fundamental frequency suppression characteristic as well as the improved output power of second harmonic. According to implementation and measurement results, it was shown that a VCHO provides an output power of -2.41 dBm, a fundamental frequency suppression of -21.84 dBc, and phase noise of -101.44 dBc/Hz at 100 kHz offset. In addition, as for the bias voltage from 0 V to -10 V for the varactor diode, output frequency range of 10.58 MHz is obtained with a power variation of ${\pm}0.19\;dB$ over its frequency range.

• Speech Sciences
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• v.15 no.1
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• pp.87-98
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• 2008

This study compares the pitch production of children using cochlear implants (CI) with that of children with normal hearing. Twenty subjects from six to eight years old participated in the study. Three kinds of sentences were read and analyzed using Visi-Pitch $\blacktriangleright$(KAY Elemetrics, Model 3300). There were no considerable differences between the two groups regarding pitch, mean fundamental frequency (F0) and pitch range. In the cases of the slope value of F0 and duration, however, there were significant differences. Thus, it is concluded that duration and pitch control can be crucial factors in determining the intonation treatment of the children with cochlear implants.

• Advances in nano research
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• v.8 no.3
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• pp.215-228
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• 2020

In this paper, a new method based on the Sander theory is developed for SWCNTs to predict the vibrational behavior of length and ratio of thickness-to-radius according to various end conditions. The motion equation for this system is developed using Rayleigh-Ritz's method. The proposed model shows the vibration frequencies of armchair (5, 5), (7, 7), (9, 9), zigzag (12, 0), (14, 0), (19, 0) and chiral (8, 3), (10, 2), (14, 5) under different support conditions namely; SS-SS, C-F, C-C, and C-SS. The solutions of frequency equations have been given for different boundary condition, which have been given in several graphs. Several parameters of nanotubes with characteristic frequencies are given and vary continuously in length and ratio of thickness-to-radius. It has been illustrated that an enhancing the length of SWCNTs results in decreasing of the frequency range. It was demonstrated by increasing of the height-to-radius ratio of CNTs, the fundamental natural frequency would increase. Moreover, effects of length and ratio of height-to-radius with different boundary conditions have been investigated in detail. It was found that the fundamental frequencies of C-F are always lower than that of other conditions, respectively. In addition, the existence of boundary conditions has a significant impact on the vibration of SWCNTs. To generate the fundamental natural frequencies of SWCNTs, computer software MATLAB engaged. The numerical results are validated with existing open text. Since the percentage of error is negligible, the model has been concluded as valid.

• Proceedings of the KSPS conference
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• 2004.05a
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• pp.199-204
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• 2004

The purpose of this paper is to find prosodic characteristics in voice imitation. Speakers change various phonetic features in voice imitation. Speakers change their pitch ranges in the most cases. Especially, the pitch range is important for word conditions. And, as imitators change the voice, the average value of f0 is close to high frequence than low frequence or middle level.

• Phonetics and Speech Sciences
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• v.13 no.4
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• pp.89-100
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• 2021

This study compared the voice range profiles (VRPs) with glissando and simplified VRP methods with 57 men who were in premutation (8-13 years), mutation (11-16 years), and postmutation (10-24 years) stages. The difference between modal and falsetto areas measured in two VRP methods was also compared. As the results, the average fundamental frequency (F0) was in the order of premuaton>mutation>postmutation. The maximum F0 (F0max), the range of F0 (F0range), the maximum intensity (Imax), and the range of intensity (Irange) were the lowest in the mutation stage, and these variables were higher in falsetto area than in modal area in both methods. In addition, most variables of VRP in glissando were higher than in simplified VRP, but the differences were not significant. This study showed that, in men in mutation stage, due to the temporary anatomical and physiological changes of the larynx, the mechanism of the vocal folds vibration changes and VRP shows a different pattern from that of other age groups. Both the VRPs of glissando and simplifed VRP are suitable for clinical practice by experienced examiners. And it is necessary to measure not only the falsetto area but also the modal area when measuring VRP.

• Phonetics and Speech Sciences
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• v.16 no.2
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• pp.37-47
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• 2024

This study was conducted on 27 male students majoring in or preparing for popular music vocals to determine whether they were aware of their voice classification and vocal range. Additionally, differences in the fundamental frequency and average speaking fundamental frequency were compared among the voice classifications. Moreover, considering that they may differ in their ability to produce high frequencies depending on the vowel, differences in voice ranges among the cardinal vowels, /a/, /i/, and /u/, were examined, and differences in voice ranges between vowels were compared by voice classification. The results showed that more than half of the male students majoring in or preparing for popular music vocals were not accurately aware of their voice types. In addition, statistically significant differences were found in the maximum fundamental frequency and frequency range among vowels, indicating differences in the voice range that can be produced depending on the vowel type. In particular, the voice range decreased in the following order: /a/>/u/>/i/. This suggests that while the vowel /a/ is easier to articulate in the high register compared to other vowels, vowels /u/ and /i/ as high vowels involve narrowing of the oral cavity due to the raised position of the tongue, accompanied by raising of the larynx, resulting in a decrease in voice range and difficulty in vocalizing in the high register.

• Speech Sciences
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• v.14 no.4
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• pp.25-39
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• 2007

The present study investigated some perceptual phonetic attributes of two Korean stop types, aspirated and lax, in medial position of an accentual phrase. The intonational pattern across syllables (Jun, 1993) is argued to depend on the type of stop (aspirated vs. lax) only in the initial position of an accentual phrase. In Kang & Dilley (2007), we showed that significant differences between aspirated and lax stops in medial position of an accentual phrase exist in closure duration, voice-onset time, and fundamental frequency (F0) values for post-stop vowels. In the present perception experiment, we investigated whether these phonetic attributes contribute to the perception of these two types of stops: The closure durations and/or F0's of post-stop vowels on accentual-phrase medial words were altered and twenty native Korean speakers then judged these words as beginning with an aspirated or lax stop. Both closure duration and F0 significantly affected judgments of stop identity. These results indicate that a wider range of acoustic cues that distinguish aspirated and lax Korean stops in production also plays a role in perception. To account for these results we suggest some phonetic and phonological models of consonant-tone interactions for Korean.