Given the interpolation rate, decimation rate and a fractional bandwidth, design a set of taps.
@param interpolation: interpolation factor @type interpolation: integer > 0 @param decimation: decimation factor @type decimation: integer > 0 @param fractional_bw: fractional bandwidth in (0, 0.5) 0.4 works well. @type fractional_bw: float @returns: sequence of numbers