[en] A digital filter can be the central unit for signal processing in the bunch-by-bunch feedback system for the TRISTAN II B-factory. Due to the 500-MHz high bunch frequency (2 ns interbunch intervals) and the large bunch number of about 5000 for TRISTAN II, we should choose a processing scheme that might be simpler and less expensive to build the electronic hardware required to implement the feedback filter and to reduce the scale of the MACs. The performance of such a simplified system should not be greatly reduced. This paper compares different FIR digital filters so that we can choose the one most suitable for TRISTAN II. These proposed digital filters are very simple, yet can satisfy the basic requirements required of them. (author)