TY - JOUR
T1 - High-fidelity PWM inverter for digital audio amplification
T2 - Spectral analysis, real-time DSP implementation, and results
AU - Pascual, César
AU - Song, Zukui
AU - Krein, Philip T.
AU - Sarwate, Dilip V.
AU - Midya, Pallab
AU - Roeckner, William Bill J.
N1 - Funding Information:
Manuscript received July 1, 2002; revised September 26, 2002. This work was supported through the joint University of Illinois/Motorola Center for Communications Research. Recommended by Associate Editor S. B. Leeb. C. Pascual, Z. Song, P. T. Krein, and D. V. Sarwate are with the Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL 61801-2018 USA (e-mail: krein@ece.uiuc.edu). P. Midya and W. J. Roeckner are with Motorola Labs, Schaumburg, IL, 60196 USA. Digital Object Identifier 10.1109/TPEL.2002.807102
PY - 2003/1
Y1 - 2003/1
N2 - A complete digital audio amplifier has been developed, implemented and tested. The process is entirely computational, and the output load and filter are the only analog components in the system. The process makes use of digital signal processing and a switching power stage to provide both high fidelity and high efficiency, beginning with a digital audio data stream. The advantages of naturally-sampled pulse-width modulation (PWM) are discussed in depth, including spectral analysis and comparisons to uniformly-sampled PWM. It is shown that natural PWM does not introduce audible distortion at switching frequencies consistent with power electronics practice. Interpolation methods for sample data conversion to natural PWM are discussed, and error analysis is presented based on Lagrange's Expansion Theorem. Noise-shaping processes are used to support high fidelity with practical values of time resolution. A counter conversion process enforces switching dead time in the inverter gate signals. The experimental full-bridge inverter implementation demonstrates that miniaturization is possible. A complete test system delivered more than 50 W into an 8 Ω load with an efficiency of 80% and total harmonic distortion plus noise of 0.02%.
AB - A complete digital audio amplifier has been developed, implemented and tested. The process is entirely computational, and the output load and filter are the only analog components in the system. The process makes use of digital signal processing and a switching power stage to provide both high fidelity and high efficiency, beginning with a digital audio data stream. The advantages of naturally-sampled pulse-width modulation (PWM) are discussed in depth, including spectral analysis and comparisons to uniformly-sampled PWM. It is shown that natural PWM does not introduce audible distortion at switching frequencies consistent with power electronics practice. Interpolation methods for sample data conversion to natural PWM are discussed, and error analysis is presented based on Lagrange's Expansion Theorem. Noise-shaping processes are used to support high fidelity with practical values of time resolution. A counter conversion process enforces switching dead time in the inverter gate signals. The experimental full-bridge inverter implementation demonstrates that miniaturization is possible. A complete test system delivered more than 50 W into an 8 Ω load with an efficiency of 80% and total harmonic distortion plus noise of 0.02%.
KW - Class D amplifier
KW - Digital audio amplifier
KW - Noise-shaping
KW - Pulse-width modulation
KW - Uniform and natural sampling
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U2 - 10.1109/TPEL.2002.807102
DO - 10.1109/TPEL.2002.807102
M3 - Article
AN - SCOPUS:0037259068
SN - 0885-8993
VL - 18
SP - 473
EP - 485
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
IS - 1 II
ER -