| 摘要 |
<p>Mixed-signal circuitry (20), including digital circuitry and analog circuitry, is operative to perform a series of operation cycles. The analog circuitry has a plurality of circuitry segments (2,4) which together produce an output signal having a frequency in a predetermined desired range of frequencies. The digital circuitry includes a digital signal generating portion (6) operable in each cycle to generate a set of digital signals (T1-Tn) for application to respective ones of the said segments (2,4), and a segment rotation section (22) operable to rotate by r segments the digital signals (T1-Tn) applied to the segments (2,4) in each cycle as compared to those applied in the preceding cycle, where r is a rotation amount for the cycle concerned. The digital circuitry further includes a rotation control section (24) for setting the rotation amount r for each cycle such that one or more rotation components, being frequency components present in a frequency spectrum of the output signal as a result of the rotation, are mapped to one or more preselected frequencies or preselected narrow bands of frequencies outside the predetermined desired range. <IMAGE></p> |
