Patent ID: 8686898

Claim:
A system employing a direct digital synthesiser (DDS), the system being adapted to use the DDS to provide a modulated signal for transmission, the modulated signal comprising at least a first followed temporally by one or more subsequent signals generated over an integration period, the first and subsequent signals having similar primary frequency characteristics, each signal having an associated starting phase, the system further incorporating an integrator for integrating signals derived from the first and subsequent modulated signals; the derived signals being comprised of intermediate frequency (IF) signals produced by mixing each signal with a delayed version of itself; wherein the DDS is provided with at least an input clock source, an input allowing control of the starting phase for each signal, and an input for controlling the DDS output frequency; wherein the DDS is arranged to generate a primary output frequency characteristic, the characteristic being the same for both the first and subsequent signals over the integration period, wherein the DDS is arranged to have at least one of the input clock source frequency and the starting phase changed between production of the first signal and a subsequent signal.