Techniques for preventing tonal behavior of data weighted averaging algorithm in /spl Sigma/-/spl Delta/ modulators

摘要

Two techniques for prevention of in-band tones in DWA mismatch noise shaping algorithm are presented. "offset technique" moves in-band tones away from baseband, improving SNR by /spl sim/10 dB, and attenuates maximum in-band tone by as much as /spl sim/25 dB. "Randomized DWA" is a combination of simultaneous randomization and DWA, which attenuates tonal behavior in all frequencies, preventing aliasing of tones or tone shifting for any arbitrary input signal.