• 제목/요약/키워드: Sigma-delta modulation

검색결과 48건 처리시간 0.03초

오버샘플링 시그마-델타 변환기의 설계와 응용 (The Design and Application of Oversampling Sigma-Delta Converters)

  • 신종한;박송배
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1991년도 하계학술대회 논문집
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    • pp.861-865
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    • 1991
  • Sigma delta modulation has been the preferred technique for oversampling conversion. In this paper we present the basic principles of oversampled sigma-delta Converters. Basic operation and theory behind sigma-delta modulation is reviewed. The different structures of the sigma-delta converters are described and the concepts of designing modulators and digital filters are discussed. The latest designs are also reviewed.

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Elimination of Idle Tones by a 2-Bit Adaptive Sigma-Delta Modulation System

  • Prosalentis, Evangelos;Tombras, George S.
    • ETRI Journal
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    • 제31권4호
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    • pp.393-398
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    • 2009
  • The operation of a first-order 2-bit adaptive sigma-delta modulation system is described and discussed in this paper. The system operation is based on the combination of both "memory" and "look-ahead" estimation in the employed step-size adaptation algorithm of the basic quantizer. In comparison to simple systems and other adaptive sigma-delta systems, computer simulation results show that these features of the described system are responsible for the high SNR values and the extended dynamic range achieved for AC signals as well as the noise power reduction of almost 10 dB and the complete elimination of the idle tones for DC signals. However, such an advantageous performance requires the least possible multiplicative error accumulation, and this cannot be achieved without analog circuits of the highest possible accuracy.

2차 Space Dithered Sigma-Delta Modulation 기반의 Random PWM 스위칭 기법을 이용한 강압형 DC-DC 컨버터의 성능 개선 (Performance Improvement of a Buck Converter using a End-order Space Dithered Sigma-Delta Modulation based Random PWM Switching Scheme)

  • 김서형;주성탁;정해광;이교범;정규범
    • 전력전자학회논문지
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    • 제14권1호
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    • pp.54-61
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    • 2009
  • 본 논문에서는 강압형 DC-DC 컨버터의 성능 개선을 위한 스위칭 기법인 2차 SDSDM (Space Dithered Sigma Delta Modulation)방식을 제안한다. PWM (Pulse Width Modulation) 방식은 일정 스위칭 주파수 대역에서의 고조파로 인해 소음, 전자파 장애, 스위칭 손실 등을 유발한다. 이러한 문제를 해결하기 위한 DSDM 방식의 일종인 1차 SDSDM은 랜덤 디더(Random Dither) 발생기가 1차 SDM의 양자화기(quatizer) 입력단에 위치하여 스위칭 주파수가 분산된다. 강압형 DC/DC 컨버터에 제안하는 2차 SDSDM의 방식을 적용한 실험 결과를 통해 타당성을 검증한다.

시그마 델타변조 방식의 노이즈 특성 (Noise characteristics in sigma-delta modulator)

  • 김상민;배창한;이광원
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 B
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    • pp.1321-1323
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    • 2000
  • Sigma-delta modulation can perform A/D conversion with a high-resolution. It is useful for simplifing the system and spreading out inband signal noise. When the sigma-delta modulation is applied to a switching converter, it can suppress the harmonic frequencies of output signal and be realized with a simple structure. In this paper, some methods of sigma-delta modulation are discussed so as to find the suitable structure for a switching converter. Noise characteristics are calculated and analyzed through simulations.

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Combined Dithered Sigma-Delta Modulation based Random PWM Switching Scheme

  • Kim, Seo-Hyeong;Choi, Woo-Jin;Choi, Se-Wan;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • 제9권5호
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    • pp.667-678
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    • 2009
  • The PWM (Pulse Width Modulation) control signals have a drawback in that their power spectrum tends to be concentrated around the switching frequency and the resulting harmonic spikes cause an EMI (Electromagnetic Interference) and switching losses in semiconductors, etc. The SDM (Sigma-Delta Modulation) is a type of switching modulation used to reduce these harmonic spikes, and several SDM schemes are investigated in this paper. In the DSDM (Dithered SDM), the SDSDM (Space-Dithered SDM) and TDSDM (Time-Dithered SDM), the signals are classified by the location of their random dither additions. In these schemes, the switching frequency is spread by a random dither generator placed on the input or the output parts. Experimental results are presented where the advantages of the new proposed CDSDM (Combined Dithered SDM) are confirmed by applying to a buck converter.

Sigma-Delta 변조기법을 이용한 Boost Converter의 전도 노이즈 저감 (Reduction of Conducted EMI Noise in Boost Converter using Sigma-Delta Modulation Technique)

  • 이성희;최태영;구자성;원충연;김규식;최세완
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2002년도 전력전자학술대회 논문집
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    • pp.494-497
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    • 2002
  • Conducted electromagnetic interference (EMI) from switch mode power supplies (SMPS) has become a major problem due to the proliferation of these devices employing dc-dc converters using standard pulse width modulation (PWM). In this paper, we proposed the sigma-delta modulation $({\sum}{\Delta}M)$ as an alternative switching technique to reduce the conducted EMI in SMPS. A comparative investigation on conducted EMI generated by PWM and ${\sum}{\Delta}M$ techniques are experimentally performed on a 300W Boost converter.

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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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LMS 알고리즘을 이용한 Sigma Delta Modulator (Improved Sigma Delta Modualtor Based On LMS Algorithm)

  • 신원화;한건희;강성호;이철희
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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    • pp.81-84
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    • 2000
  • This paper proposes a new sigma delta modulator structure based on a LMS(Least Mean Square) algorithm that minimizes the quantization noise. The proposed architecture provides 40dB SNR improvement and 35dB wider dynamic range over conventional sigma delta modulation. The proposed architecture provides superior performance especially when the input signal is small.

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랜덤 스위칭 주기를 갖는 시그마 델타 변조기 (A Sigma-Delta Modulator With Random Switching Periods)

  • 배창한;김상민;이광원
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제50권10호
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    • pp.513-519
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    • 2001
  • This paper proposed a random sigma-delta modulator(RSDM), which is constructed by a 1st order sigma-delta modulator(SDM) and a simple structured random binary generator(RBG). The 1st order SDM produces a switching pulse waveform which has the same low-frequency component as the reference input, while the RBG spreads the distribution of the number of sampling per switching cycle, and thus disperses the spectrum spikes in the output. The relationship between the harmonic spectra and the number of sampling per switching cycle is studied through computer simulations, and the frequency spectra of the RSDM are confirmed in an experimental setup.

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Fractional-N Frequency Synthesis: Overview and Practical Aspects with FIR-Embedded Design

  • Rhee, Woogeun;Xu, Ni;Zhou, Bo;Wang, Zhihua
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제13권2호
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    • pp.170-183
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    • 2013
  • This paper gives an overview of fractional-N phase-locked loops (PLLs) with practical design perspectives focusing on a ${\Delta}{\Sigma}$ modulation technique and a finite-impulse response (FIR) filtering method. Spur generation and nonlinearity issues in the ${\Delta}{\Sigma}$ fractional-N PLLs are discussed with simulation and hardware results. High-order ${\Delta}{\Sigma}$ modulation with FIR-embedded filtering is considered for low noise frequency generation. Also, various architectures of finite-modulo fractional-N PLLs are reviewed for alternative low cost design, and the FIR filtering technique is shown to be useful for spur reduction in the finite-modulo fractional-N PLL design.