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ABSTRACT: This paper presents novel modulation and pre-equalization methods to minimize a signal processing time delay in the equalization digital on-channel repeater (EDOCR) for the ATSC terrestrial digital TV system. The proposed modulation method uses equi-ripple (ER) filter for vestigial side bands (VSB) pulse shaping instead of conventional square root raised cosine (SRRC) filter. And the proposed pre-equalization method calculates pre-equalizer filter coefficients by comparing a baseband signal as a reference signal and a demodulated repeater output signal, and then creates new VSB pulse shaping filter coefficients by the convolution of the ER filter and the pre-equalizer filter coefficients. The new VSB pulse shaping filter minimizes the time delay of EDOCR by adjusting the number of its pre-taps and also compensates the linear distortions due to the use of the ER filter and mask filter.
IEEE Transactions on Broadcasting 07/2008; · 1.70 Impact Factor
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ABSTRACT: Digital On-Channel Repeater (DOCR) can be used for Single Frequency Networks (SFN's). It is much simple and low cost compared to Distributed Transmitter which needs Studio to Transmitter Link (STL). However, traditional DOCR has one of those defects such as a power limit, a long time system processing delay or a poor output signal quality. In order to overcome all of those defects, we introduce Equalization DOCR (EDOCR) which regenerates the original 8-VSB output signal with relatively short time system processing delay. Lab. and Field test results show that the EDOCR can eliminate the loop-back signal up to 5.5 dB with 5.5 μs system processing delay. By using EDOCR, we can save spectrum resources and extend coverage areas.
IEEE Transactions on Broadcasting 07/2006; · 1.70 Impact Factor
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ABSTRACT: In this paper we propose a novel modulator for the equalization digital on-channel repeater (EDOCR) in ATSC system. The proposed modulator uses equi-ripple VSB filter instead of conventional square root raised cosine (SRRC) filter. Since the time delay of the EDOCR modulator can seriously affect the performance of ATSC legacy receivers, it is required that the processing time should be minimized as much as possible. So, the proposed modulator focuses on reduction of time delay with minimization of its performance degradation. By simulation results, the proposed modulator has not only relative short time delay, but also little performance degradation. Also, proposed modulator using ER filter satisfies FCC RF emission mask.
Consumer Electronics, 2006. ICCE '06. 2006 Digest of Technical Papers. International Conference on; 02/2006
