• Title/Summary/Keyword: Digital Audio Amplifier

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Stability of Digital Audio Amplifier and Analysis on the Effect of Hysteresis (디지털 오디오 앰프의 안정성과 히스테리시스에 의한 영향 해석)

  • Doh, Tae-Yong;Jang, Byung-Tak;Ryoo, Tae-Ha;Ryoo, Ji-Yeol;Park, Hwan-Wook
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.605-607
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    • 2004
  • A class D digital audio amplifier with small size, low cost, and high quality is positively necessary in the multimedia era made of home theater system and the digital audio broadcasting (DAB). It is impossible to analyze the stability of the digital audio amplifier, which is based on the PWM signal processing. To solve this problem, the digital audio amplifier is analyzed using variable structure control theory which is one of nonlinear system theories. Moreover, the magnitude and the frequency of ripple signal, which generated by hysteresis in the comparator, is obtained using describing function which is useful to represent the input-output relation of nonlinear system.

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Modeling and Analysis of Class D Audio Amplifiers using Control Theories (제어이론을 이용한 D급 디지털 오디오 증폭기의 모델링과 해석)

  • Ryu, Tae-Ha;Ryu, Ji-Yeol;Doh, Tae-Yong
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.4
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    • pp.385-391
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    • 2007
  • A class D digital audio amplifier with small size, low cost, and high quality is positively necessary in the multimedia era. Since the digital audio amplifier is based on the PWM signal processing, it is improper to analyze the principle of signal generation using linear system theories. In this paper, a class D digital audio amplifier based ADSM (Advanced Delta-Sigma Modulation) is considered. We first model the digital audio amplifier and then explain the operation principle using variable structure control algorithm. Moreover, the ripple signal generated by the hysteresis in the comparator has a significant effect on the system performance. Thus, we present a method to find the magnitude and the frequency of the ripple signal using describing function. Finally, simulations and experiments are provided to show the validity of the proposed methods.

Interpolated Digital Delta-Sigma Modulator for Audio D/A Converter (오디오 D/A 컨버터를 위한 인터폴레이티드 디지털 델타-시그마 변조기)

  • Noh, Jinho;Yoo, Changsik
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.11
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    • pp.149-156
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    • 2012
  • A digital input class-D audio amplifier is presented for digital hearing aid. The class-D audio amplifier is composed of digital and analog circuits. The analog circuit converts a digital input to a analog audio signal (DAC) with noise suppression in the audio band. An interpolated digital delta-sigma modulator is used to convert data types between digital signal processor (DSP) and digital-to-analog converter (DAC). An 16-bit, 25-kbps pulse code modulated (PCM) input is interpolated to 16-bit, 50-kbps by a digital filter. The output signal of interpolation filter is noise-shaped by a third-order digital sigma-delta modulator (SDM). As a result, 1.5-bit, 3.2-Mbps signal is applied to simple digital to analog converter.

Low-Power and High-Efficiency Class-D Audio Amplifier Using Composite Interpolation Filter for Digital Modulators

  • Kang, Minchul;Kim, Hyungchul;Gu, Jehyeon;Lim, Wonseob;Ham, Junghyun;Jung, Hearyun;Yang, Youngoo
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.1
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    • pp.109-116
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    • 2014
  • This paper presents a high-efficiency digital class-D audio amplifier using a composite interpolation filter for portable audio devices. The proposed audio amplifier is composed of an interpolation filter, a delta-sigma modulator, and a class-D output stage. To reduce power consumption, the designed interpolation filter has an optimized composite structure that uses a direct-form symmetric and Lagrange FIR filters. Compared to the filters with homogeneous structures, the hardware cost and complexity are reduced by about half by the optimization. The coefficients of the digital delta-sigma modulator are also optimized for low power consumption. The class-D output stage has gate driver circuits to reduce shoot-through current. The implemented class-D audio amplifier exhibited a high efficiency of 87.8 % with an output power of 57 mW at a load impedance of $16{\Omega}$ and a power supply voltage of 1.8 V. An outstanding signal-to-noise ratio of 90 dB and a total harmonic distortion plus noise of 0.03 % are achieved for a single-tone input signal with a frequency of 1 kHz.

A novel controller for switching audio power amplifier with digital input (디지털 PWM 입력 D급 음향 증폭기를 위한 새로운 제어기법)

  • Park, Jong-Hu;Kim, C.G.;Cho, B.H.
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.976-979
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    • 2002
  • A new controller for switching audio power amplifier with digital PWM input is proposed- Bi-directional Saw-tooth Error Correction (BSEC). This control method for high quality switching amplifier is based on a pulsed edge correction approach using PWM audio signal input as a reference of power switching digital to analog converter. The proposed controller has excellent features such as wide error correction range and no limitation on the modulation index. The controller is implemented in the half-bridge class D amplifier and the performance is verified through hardware experiments. It delivers 100W into 4${\Omega}$ load with less than 0.2% of total harmonic distortion (THD) all over operating range and an maximum efficiency of 82%.

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A New High Efficiency and Low Pronto On-Board DC/DC Converter for Digital Car Audio Amplifier

  • Kim Chong-Eun;Han Sang-Kyoo;Moon Gun-Woo
    • Proceedings of the KIPE Conference
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    • 2004.07b
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    • pp.601-605
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    • 2004
  • A new high efficiency and low profile on-board DC/DC converter for digital car audio amplifier is proposed. The proposed converter shows the continuous input current, no DC excitation current of the transformer, the minimized electro-magnetic interference (EMI), no output inductor, and the low voltage stress of the secondary rectifier diodes. The 60W industrial sample of the proposed converter is implemented for digital car audio amplifier and the measured efficiency is $88.3\%$ at nominal input voltage.

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Design of an S/PDIF 7.1-Channel Digital Amplifier for Home Theater Speakers (홈시어터 스피커를 위한 S/PDIF 7.1 채널 디지털 앰프의 구현)

  • Kwon, Oh-Kyun;Song, Moon-Vin;Jun, Kye-Suk;Chung, Yun-Mo
    • The Journal of the Acoustical Society of Korea
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    • v.26 no.5
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    • pp.188-193
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    • 2007
  • In general, analog amplifiers for 5.1 or more channels have been used to configure home theater systems. In order to make high-performance systems, it is desirable to process audio signals in digital techniques in consideration of output and efficiency of speakers. Especially we need 7.1-channel system to separate audio signals efficiently. In this paper we implemented the architecture of S/PDIF 7.1-channel digital amplifier for home theater systems. The amplifier shows good performance with less loss of original sounds because of both strong characteristics against noises and direct processing of input data.

A New High Efficiency and Low Profile On-Board DC/DC Converter for Digital Car Audio Amplifiers

  • Kim Chong-Eun;Han Sang-Kyoo;Moon Gun-Woo
    • Journal of Power Electronics
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    • v.6 no.1
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    • pp.83-93
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    • 2006
  • A new high efficiency and low profile on-board DC/DC converter for digital car audio amplifiers is proposed. The proposed converter shows low conduction loss due to the low voltage stress of the secondary diodes, a lack of DC magnetizing current for the transformer, and a lack of stored energy in the transformer. Moreover, since the primary MOSFETs are turned-on under zero-voltage-switching (ZVS) conditions and the secondary diodes are turned-off under zero-current-switching (ZCS) conditions, the proposed converter has minimized switching losses. In addition, the input filter can be minimized due to a continuous input current, and an output inductor is absent in the proposed converter. Therefore, the proposed converter has the desired features, high efficiency and low profile, for a viable power supply for digital car audio amplifiers. A 60W industrial sample of the proposed converter has been implemented for digital car audio amplifiers with a measured efficiency of $88.3\%$ at nominal input voltage.

Compensation of the Non-linearity of the Audio Power Amplifier Converged with Digital Signal Processing Technic (디지털 신호 처리 기술을 융합한 음향 전력 증폭기의 비선형 보상)

  • Eun, Changsoo;Lee, Yu-chil
    • Journal of the Korea Convergence Society
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    • v.7 no.3
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    • pp.77-85
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    • 2016
  • We propose a digital signal processing technic that can compensate the non-linearity inherent in audio amplifiers, and present the result of the simulation. The inherent non-linearity of the audio power amplifier arising from analog devices is compensated via a digital signal processing technic consisting of indirect learning architecture and an adaptive filter. The simulation results show that the compensator can be realized using a third-order polynomial and compensates odd-order non-linearity efficiently. The even-oder non-linearity is mainly due to the dc offset at the output, which is difficult to eliminate with the proposed method. Care must be taken in designing the bias circuit to avoid the DC offset at the output. The proposed technic has significance in that digital signal processing technic can compensate for the impairment that is an inherent characteristic of an analog system.

RF Receiver design for Satellite Digital Audio Reception (Antenna)

  • Kim, Jang-Wook;Jeon, Joo-Seong
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.7
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    • pp.71-78
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    • 2019
  • This paper describes a design for a RF receiver to receive satellite digital audio service. The RF receiver designed in this study is a planar structure that is easy to install on the rooftop of a car and is compact in size. In addition, it can be applied to certain commercial models because it has low noise and high gain characteristics. The impedance bandwidth of antenna is 17.8%(415MHz), and the axial ratio is below 3dB as good properties for the bandwidth of 40MHz which is a satellite digital audio service band. Also, it had a broad radiation beamwidth of $95.41^{\circ}$ in H-plane and $117.45^{\circ}$ in E-plane. From the results of the field test of satellite digital audio service reception for the RF receiver, it demonstrated good C/N rate(10.2dB).