NDLI: Spectral Regrowth Reduction for Digital Audio Broadcasting Using EER Amplifiers

Content Provider	IEEE Xplore Digital Library
Author	Walker, B.W. Ilow, J.
Copyright Year	2008
Description	Author affiliation: Dept. of Electr. & Comput. Eng., Dalhousie Univ., Halifax, NS (Walker, B.W.; Ilow, J.)
Abstract	For the amplitude modulation (AM) radio broadcast band, there are several standards being considered for digital audio broadcast (DAB), all using orthogonal frequency-division multiplexing (OFDM). One of the main challenges to implementing digital audio broadcasting is that existing broadcast equipment was not designed for it. Unlike analog AM, which is a low bandwidth amplitude modulated signal, OFDM is a noise-like signal with significant amplitude and phase modulation. Most AM transmitters use an envelope elimination and restoration (EER) amplifier architecture, where the amplitude and phase components of the signal are amplified separately then recombined at the high power stage. The magnitude and phase component bandwidths are several times that of the input signal, and any filtering in the amplifier will result in spectral regrowth due to poor cancellation of this high frequency content. This paper develops the concept of using time-domain preprocessing on the signal to reduce the bandwidth expansion in EER amplifiers. The processing exploits the localization of the bandwidth expansion and its correlation with spectral regrowth at the output. The proposed algorithm identifies distortion- causing signal sections and replaces each one with an alternative signal trajectory. Using the processing, out of band emissions are reduced at the expense of increased computational complexity and error vector magnitude. Promising results are shown for the DRM 10 kHz digital signal, with reductions in spectral regrowth of up to 10 dB.
Starting Page	185
Ending Page	190
File Size	511211
Page Count	6
File Format	PDF
ISBN	9780769531359
DOI	10.1109/CNSR.2008.90
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2008-05-05
Publisher Place	Canada
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Digital audio broadcasting Bandwidth Amplitude modulation Radio broadcasting Phase modulation Signal processing Radiofrequency amplifiers Frequency division multiplexing OFDM modulation Noise level Spectral Regrowth Reduction Digital Audio Broadcasting OFDM EER Amplifiers
Content Type	Text
Resource Type	Article

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