Sparse equalizer using adaptive weight activation for fast start-up in ATSC DTV systems

Vestigial sideband (VSB) modulation for digital television (DTV) systems transmits a training sequence called field sync (FS) every 3/3 segments with a period 0/24.2 ms. The field sync sequence, however, is not long enough to guarantee the operation of an equalizer. So it requires many field sync sequences for the convergence of an equalizer with long taps in severely distorted channels. In this paper, a sparse equalizer using a data-recycling algorithm is proposed for fast convergence of the equalizer in 8-VSB systems. The proposed sparse equalizer with a data-recycling algorithm, utilizing one FS sequence for several times, selects effective equalizer taps for channel equalization and improves the convergence speed and output signal-to-noise ratio (SNR). The effectiveness of the proposed equalizer is evaluated from the points of the output SNR, convergence speed, and the number of required taps in Brazilian test channels and a single ghost dynamic channel.