Patent ID: 8040971

Claim:
A digital circuit for use in a mixed-signal circuit, said digital circuit comprising a first circuit for direct digital synthesis comprising a first phase generator arranged for being fed with a phase generator input signal, a first phase-to-amplitude converter arranged for being fed with a phase from said first phase generator and for generating a first carrier wave output, and first signal combining means for combining said first carrier wave output with a first input signal, a noise generator arranged for generating a pseudo-random noise signal, combining means for combining said pseudo-random noise signal and said phase generator input signal such that said phase generator input signal to said first phase generator is randomised, a second circuit for direct digital synthesis comprising a second phase generator arranged for being fed with said pseudo-random noise signal, a second phase-to-amplitude converter arranged for being fed with a phase from said second phase generator and for generating a second carrier wave output, and second signal combining means for combining said second carrier wave output with a second input signal, whereby said second carrier wave output combined with said second input signal is comprised in said first input signal.