Patent ID: 6456218
Filing Date: 2002-09-24
Classification: H03M

Abstract:
Mixed-signal circuitry, comprising digital circuitry and analog circuitry, operative to perform a series of operation cycles, wherein:said analog circuitry has a plurality of circuitry segments which together produce an output signal having a frequency in a predetermined desired range of frequencies; and the digital circuitry comprises: digital signal generating circuitry operable in each said cycle to generate a set of digital signals for application to respective ones of said segments; rotating circuitry operable to rotate by r segments the digital signals applied to the segments in each cycle as compared to those applied in the preceding cycle, where r is a rotation amount for the cycle concerned; and rotation control circuitry which sets said rotation amount r for each said cycle such that one or more rotation components, being frequency components present in a frequency spectrum of said output signal as a result of said rotation, are mapped to one or more preselected frequencies or preselected narrow bands of frequencies outside said predetermined desired range.