The present invention provides a probability mass redistributor device comprising an input port and an output port. The device comprises a mapping block configured to perform a selected mapping function from a plurality of mapping functions on a random bitstream to generate an output signal having a desired probability mass function, at least one difference block, wherein the input to the at least one difference block comprises the output from the mapping block, and the output of the at least one difference block produces a modulation term, and wherein the output of each difference block is the difference between a previous value of the input signal to the block and a current value of the input signal to the block, and a summing block for summing a signal received by the input port and the modulation term to form an output signal.