| 摘要 |
An equalizer ( 34 ) and a prefilter ( 1 ) used in conjunction with a comb filter ( 2 ) in a High Definition Television (HDTV) system. The prefilter ( 1 ) may be placed before the comb filter ( 2 ), or alternatively may be placed after the comb filter. Further, the method may be enhanced by estimating the filter tap when the prefilter ( 1 ) is placed after the comb filter ( 2 ). The equalizer ( 34 ) produces a fifteen level output from the eight level Vestigial Sideband (VSB) input without limiting the amplitude at symbol 12 to a relatively small value, such as -20 dB. Three specific methods of increasing the permissible amplitude at symbol 12 are presented which permit tap 12 amplitudes as high as -6 dB.
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