LSB Dithering in MASH Delta–Sigma D/A Converters

Recent advances in the analysis, design and optimization of Digital Delta-Sigma Modulators

“…This is equivalent to adding filtered dither at the input. Pamarti and Galton [12] have proven that LSB dither can be filtered effectively to Rth order if R ≤ l − 2. However, when R > l − 2, spurs reappear in the output spectrum, as illustrated in Fig.…”

Hardware Reduction in Digital Delta-Sigma Modulators Via Error Masking - Part I: MASH DDSM

“…However, when the cycle length of a DDSM output is not sufficiently large, one can observe discrete tones clearly in the power spectrum. The locations of these tones are given by (6) where is the index of the tone. Fig.…”

“…In the case of additive input dithering of a MASH system [6], a 1-bit dither pseudorandom signal filtered by a shaping filter is added to the LSBs of a desired signal as shown in Fig. 24.…”

“…The "stochastic" approach to maximizing cycle lengths is to use a "random" 1 dither signal to disrupt periodic cycles [6]. Dithering breaks up the cycles and increases the effective cycle length, resulting in smooth noise-shaped spectra.…”

Architectures for Maximum-Sequence-Length Digital Delta-Sigma Modulators

“…1) to the input [10], [11]. This breaks up the cycles and increases the effective sequence length, resulting in a smoother noise-shaped spectrum.…”