• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.2
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• pp.135-139
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• 1999

Objectives : The purpose of this study was to systematically analyze and compare the acoustic characteristics of vocal major students with vocal nodule when singing. Materials and Methods : Ten sopranos with vocal nodule, who have never been treated due to voice problems, were the subject group. Twenty healthy sopranos major students were the control group for this study. The vocal nodule was confirmed by stroboscopy and the acoustic and electroglottographic analysis was conducted on be groups. Additionally, an inquiry on usual voice problems during speaking and singing were performed on each of the groups. Results : The vowel /a/ was spoken and sung by sopranos of each group. There were no significant differences in Fo, jitter, shimmer, NHR at speaking and singing in either group. We did not register any significant differences of closed quotient and speed quotient in electroglottography for both groups at singing, but speed quotient was increased in subject group at speaking(p＜0.05). And the sopranos with nodule demonstrated voice fatigue(70%), strained and tired voice after long period of performance and conversation(60%) on inquiry. Conclusions : Although they had a vocal nodule, this group, who had a long period of voice training, did not present any differences in acoustic and electroglottographic problems during short performance, but, the vocalists noticed delicate voice problems after a long performance. We conclude that the voice training teacher and laryngologist must initiate voice management and speech therapy for vocal nodule, even if there is no specific abnormality in acoustic analysis.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.56-61
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• 2001

This paper presents the real-time implementation of an AMR (Adaptive Multi Rate) vocoder which is included in the asynchronous International Mobile Telecommunication (IMT)-2000 mobile ASIC. The implemented AMR vocoder is a multi-rate coder with 8 modes operating at bit rates from 12.2kbps down to 4.75kbps. Not only the encoder and the decoder as basic functions of the vocoder are implemented, but VAD (Voice Activity Detection), SCR (Source Controlled Rate) operation and frame structuring blocks for the system interface are also implemented in this vocoder. The DSP for AMR vocoder implementation is a 16bit fixed-point DSP which is based on the TeakLite core and consists of memory block, serial interface block, register files for the parallel interface with CPU, and interrupt control logic. Through the implementation, we reduce the maximum operating complexity to 24MIPS by efficiently managing the memory structure. The AMR vocoder is verified throughout all the test vectors provided by 3GPP, and stable operation in the real-time testing board is also proved.