A finite impulse response filter of 1:4 interpolation with 108 taps for
outputting filter output data of 8 bits with respect to filter input data
of 4 bits includes four shifting and storing unit of 27 bits for unifying
bits of filter input data of 4 bits, which is 2's complement to shift and
store the bi-unified input data, first selection unit for selecting any
one of the input data stored in the four shifting and storing unit of 27
bits, address generating unit for generating addresses of lookup tables
corresponding to each of a plurality of filter coefficients groups, first
to fourth lookup table groups for generating filter outputs of each filter
coefficients group, four accumulating unit for shifting the filter outputs
of the filter coefficients groups respectively outputted in parallel from
the first to the fourth lookup table groups, and second selection unit for
serially converting the outputs from each of the four accumulators in
accordance with filter coefficients groups.
