• 제목/요약/키워드: envelope signal

검색결과 206건 처리시간 0.02초

음성 하모닉스 스펙트럼의 피크-피팅을 이용한 피치검출에 관한 연구 (A Study on the Pitch Detection of Speech Harmonics by the Peak-Fitting)

  • 김종국;조왕래;배명진
    • 음성과학
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    • 제10권2호
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    • pp.85-95
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    • 2003
  • In speech signal processing, it is very important to detect the pitch exactly in speech recognition, synthesis and analysis. If we exactly pitch detect in speech signal, in the analysis, we can use the pitch to obtain properly the vocal tract parameter. It can be used to easily change or to maintain the naturalness and intelligibility of quality in speech synthesis and to eliminate the personality for speaker-independence in speech recognition. In this paper, we proposed a new pitch detection algorithm. First, positive center clipping is process by using the incline of speech in order to emphasize pitch period with a glottal component of removed vocal tract characteristic in time domain. And rough formant envelope is computed through peak-fitting spectrum of original speech signal infrequence domain. Using the roughed formant envelope, obtain the smoothed formant envelope through calculate the linear interpolation. As well get the flattened harmonics waveform with the algebra difference between spectrum of original speech signal and smoothed formant envelope. Inverse fast fourier transform (IFFT) compute this flattened harmonics. After all, we obtain Residual signal which is removed vocal tract element. The performance was compared with LPC and Cepstrum, ACF. Owing to this algorithm, we have obtained the pitch information improved the accuracy of pitch detection and gross error rate is reduced in voice speech region and in transition region of changing the phoneme.

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Bandwidth and Power Efficient Constant-Envelope BPSK Signals

  • Park, Hyung-Chul
    • 한국통신학회논문지
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    • 제29권6A호
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    • pp.683-689
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    • 2004
  • The power and bandwidth efficient constant-envelope BPSK (CE-BPSK) modulation is proposed. The CE-BPSK signal is realized specifying the phase transition characteristics for the conventional low pass filtered BPSK signal. Since the CE-BPSK signal has constant envelope and modified waveform, the CE-BPSK signal has better power and bandwidth efficiency compared to the conventional BPSK signal while the CE-BPSK signal is backward compatible to the conventional BPSK signal. It is also shown that the bit error rate performance of the CE-BPSK signal is the same as that of the conventional BPSK signal.

HIV-1 Retroviral Vector System의 개발 및 $CD4^+$ T 세포에서 HIV-1 Envelope 당단백질의 발현 (Development and Utilization of an Human Immunodeficiency Virus Type 1 (HIV-1)-Based Retroviral Vector System to Express HIV-1 Envelope Glycoprotein in $CD4^+$ T Cells)

  • 박진서
    • 대한바이러스학회지
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    • 제26권2호
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    • pp.141-150
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    • 1996
  • 본 연구에서는 $CD4^+$ T 세포를 일회성으로 감염시킬 수 있고 $CD4^+$ T 세포에 HIV-1 envelope 유전자를 전달할 수 있는 바이러스 입자를 생산하는 HIV-1 complementation system을 개발하였고 이 system을 이용하여 $CD4^+$ T 세포에 선택적으로 HIV-1 envelope 당단백질을 발현시켰다. 이 system은 Gag/Gag-Pol expressor와 Env expressor로 구성되어있다. Gag/Gag-Pol expressor는 바이러스 입자 생산에 필요한 구조단백질과 기능단백질을 발현시키지만 packaging signal이 결핍되어 바이러스 입자로 유전자가 들어가지 못하도록 제조되었다. Env expressor는 Tat, Rev와 envelope 당단백질을 발현시키고 packaging signal을 갖고 있어 바이러스 입자로 envelope 유전자가 들어가도록 제조되었다. Gag/Gag-Pol expressor로부터 Gag와 Gag-Pol의 발현은 Rev 단백질을 요구하였고 Env expressor로부터 Rev 단백질 이 제공될 때 Gag와 Gag-Pol 단백질은 효율적으로 발현되었다. Gag/Gag-Pol과 Env expressor로 cotransfection된 COS-1 세포에서 $CD4^+$ T 세포를 일회성으로 감염시킬 수 있는 바이러스 입자가 생산되었다. 생산된 바이러스 입자는 $CD4^+$ T 세포에 HIV-1 envelope 유전자를 전달하여 envelope 당단백질을 발현시켰고 복제 가능한 자손 바이러스의 생성을 유도하지 못하였다. 본 연구에서 개발된 방법은 $CD4^+$ T 세포에서 envelope 당단백질의 기능을 분석하고 관심 있는 유전자를 $CD4^+$ T 세포에 전달하는 바이러스 입자의 생산에 이용할 수 있다.

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Binary Power Amplifier with 2-Bit Sigma-Delta Modulation Method for EER Transmitter

  • Lim, Ji-Youn;Cheon, Sang-Hoon;Kim, Kyeong-Hak;Hong, Song-Cheol;Kim, Dong-Wook
    • ETRI Journal
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    • 제30권3호
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    • pp.377-382
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    • 2008
  • A novel power amplifier for a polar transmitter is proposed to achieve better spectral performance for a wideband envelope signal. In the proposed scheme, 2-bit sigma-delta (${\Sigma}{\Delta}$) modulation of the envelope signal is introduced, and the power amplifier configuration is modified in a binary form to accommodate the 2-bit digitized envelope signals. The 2-bit ${\Sigma}{\Delta}$ modulator lowers the noise of the envelope signal by fine quantization and thus enhances the spectral property of the RF signal. The Ptolemy simulation results of the proposed structure show that the spectral noise is reduced by 10 dB in a full transmit band of the EDGE system. The dynamic range is also enhanced. Since the performance is improved without increasing the over-sampling ratio, this technique is best suited for wireless communication with high data rates.

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음장의 공간 복소 포락: 정의와 특성 (Spatial Complex Envelope of Acoustic Field : Its Definition and Characteristics)

  • 박춘수;김양한
    • 한국소음진동공학회논문집
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    • 제17권8호
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    • pp.693-700
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    • 2007
  • We can predict spatial acoustic pressure distribution on the plane of interest by using acoustic holography. However, the information embedded in the distribution plot is usually much more than what we need: for example, source locations and their overall propagation pattern. One possible candidate to solve the problem is complex envelope analysis. Complex envelope analysis extracts slowly-varying envelope signal from a band signal. We have attempted to extend this method to space domain so that we can have spatial information that we need. We have to modulate two dimensional data for obtaining spatial envelope. Although spatial modulation basically follows the same concept that is used in time domain, the algorithm for the spatial modulation turns out to be different from temporal modulation. We briefly describe temporal complex envelope analysis and extend it to spatial envelope of 2-D acoustic field by introducing geometric transformation. In the end, the results of applying the spatial envelope to the holography are envisaged and verified.

Ultrasonic Distance Measurement Method by Using the Envelope Model of Received Signal Based on System Dynamic Model of Ultrasonic Transducers

  • Choe, Jin-Hee;Lee, Kook-Sun;Choy, Ick;Cho, Whang
    • Journal of Electrical Engineering and Technology
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    • 제13권2호
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    • pp.981-988
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    • 2018
  • In order to acquire an accurate TOF, this paper proposes a method that produces TOF by using a mathematical model for the envelope of the received signal obtained from a system dynamic model of ultrasonic transducer. The proposed method estimates the arrival time of the received signal retrospectively by comparing its wave form obtained after triggering point with its mathematical envelope model. Experimental result shows that the error due to variation of triggering point can be dramatically decreased by implementing the proposed method.

다상포결선검파법에 의한 생체신호의 검출에 관한 연구 (A Study on Observation Techniques of Physiological Signal by Polyphase Envelope Detection)

  • 이충웅
    • 대한전자공학회논문지
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    • 제15권5호
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    • pp.25-28
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    • 1978
  • 생체로 부터의 전기적인 파형의 관찰 및 기록에 있어서 파형의 포각선이 불명확하여 생체반응의 판단 또는 생체신호의 데이터처리가 곤란한 경우가 많다. 본 논문에서는 이 문제를 다상포각선검파법을 응용하여 종전에는 관측하기 어려됐던 생체신호의 포각선을 관측할 수 있음을 제시하였다.

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3-Level Envelope Delta-Sigma Modulation RF Signal Generator for High-Efficiency Transmitters

  • Seo, Yongho;Cho, Youngkyun;Choi, Seong Gon;Kim, Changwan
    • ETRI Journal
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    • 제36권6호
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    • pp.924-930
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    • 2014
  • This paper presents a $0.13{\mu}m$ CMOS 3-level envelope delta-sigma modulation (EDSM) RF signal generator, which synthesizes a 2.6 GHz-centered fully symmetrical 3-level EDSM signal for high-efficiency power amplifier architectures. It consists of an I-Q phase modulator, a Class B wideband buffer, an up-conversion mixer, a D2S, and a Class AB wideband drive amplifier. To preserve fast phase transition in the 3-state envelope level, the wideband buffer has an RLC load and the driver amplifier uses a second-order BPF as its load to provide enough bandwidth. To achieve an accurate 3-state envelope level in the up-mixer output, the LO bias level is optimized. The I-Q phase modulator adopts a modified quadrature passive mixer topology and mitigates the I-Q crosstalk problem using a 50% duty cycle in LO clocks. The fabricated chip provides an average output power of -1.5 dBm and an error vector magnitude (EVM) of 3.89% for 3GPP LTE 64 QAM input signals with a channel bandwidth of 10/20 MHz, as well as consuming 60 mW for both channels from a 1.2 V/2.5 V supply voltage.

하모닉 구조 확장과 NMF 기반의 인공 대역 확장 기술 (Artificial Bandwidth Extension Based on Harmonic Structure Extension and NMF)

  • 김기준;박호종
    • 전자공학회논문지
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    • 제50권12호
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    • pp.197-204
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    • 2013
  • 본 논문에서는 주파수 영역에서 협대역 신호를 광대역으로 확장하는 새로운 인공 대역 확장 기술을 제안한다. 제안한 기술은 협대역 신호를 여기 신호와 스펙트럼 포락선 성분으로 분리하고, 주파수 영역에서 각각 독립적인 방법으로 확장한다. 여기 신호는 저대역의 하모닉 구조가 고대역에서 유지되도록 확장하고, 스펙트럼 포락선은 부대역별 에너지를 기반으로 NMF방법으로 확장한다. 마지막으로 시간 축에서 프레임 사이의 상관관계를 기반으로 스펙트럼 위상을 결정하여 최종 광대역 신호를 생성한다. 주관적 청취 평가를 통하여 제안한 방법으로 대역 확장된 신호가 원 협대역 신호보다 음질이 향상된 것을 확인하였다.

Envelope ADI-FDTD의 수치적 특성에 관한 연구 (A Study of the Numerical Characteristics of the Envelope ADI-FDTD)

  • 주세훈;정경영;김형훈;김형동
    • 한국전자파학회논문지
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    • 제14권6호
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    • pp.584-590
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    • 2003
  • 본 논문에서는 최근에 개발된 Envelope ADI-FDTD의 수치적 특성에 대하여 고찰하였다. 수치 실험을 통하여 Envelope ADI-FDTD가 시간간격에 상관없이 무조건 안정하고, 신호의 포락선을 해석함으로써 기존의 ADI-FDTD보다 더 좋은 분산특성을 얻을 수 있음을 보였다. 이러한 특성은 특별한 경우에서는 Nyquist 극한값까지 시간간격을 키울 수 있는 가능성을 제공한다 수치결과를 통해서 Envelope ADI-FDTD가 단일주파수 또는 대역이 제한된 시스템의 해석에 있어 유용하게 사용될 수 있음을 확인하였다.