In this paper, according to the multi-channel model of the fractionally spaced linear equalizers, the symbol-spaced adaptive decision feedback equalizers (ADFE) are extended to the fractionally spaced adaptive decision feedback equalizers (FSADFE). We applied the FSADFE to the ATSC DTV receivers. The ADFE converges very slowly when the channel presents severe characteristic that results in poor performance. FSADFE can deal with this DFE weakness and the performance gain between them is considerable. This gain benefits the DTV receivers, especially in some severe channels.