Patent ID: 7668249

Claim:
A digital modulation system comprising: an in-phase modulation data input adapted to receive in-phase input modulation data comprising in-phase input data samples and representing an in-phase modulation signal; a quadrature-phase modulation data input adapted to receive quadrature-phase input modulation data comprising quadrature-phase input data samples and representing a quadrature-phase modulation signal; and digital modulation circuitry adapted to: rate convert and interpolate the in-phase input modulation data to generate in-phase output modulation data comprising in-phase output data samples and representing the in-phase modulation signal; and rate convert and interpolate the quadrature-phase input modulation data to generate quadrature-phase output modulation data comprising quadrature-phase output data samples and representing the quadrature-phase modulation signal, wherein in a given time period a ratio of a number of in-phase output data samples to a number of in-phase input data samples is at least two to one, the in-phase modulation signal and the quadrature-phase modulation signal represent in-phase and quadrature-phase components of a complex modulation signal, and the in-phase input data samples and the quadrature-phase input data samples are collected in separate sets of input data samples, wherein each set of input data samples is processed using an interpolation method comprising polynomial curve fitting to create a set of output data samples, which is used to provide the in-phase output data samples and the quadrature-phase output data samples.