Multi-stAge Noise SHaping Digital Delta-sigma Modulator Research Articles

MASH DDSM with Negative Feedback

This paper proposes a Multi-stAge noise SHaping (MASH) digital delta-sigma modulator (DDSM) with negative feedback to acquire the maximum sequence length. The mathematical analysis shows that the sequence length is [Formula: see text], which is not affected by the input values and initial conditions, where [Formula: see text] is the smallest prime number above the quantization interval [Formula: see text], and [Formula: see text] is the order of the MASH DDSM. Moreover, the influence of the negative feedback on the input range is analyzed. Finally, the simulations and experiments are performed to verify the theoretical analysis.

Mathematical calculation of sequence length in LFSR-dithered MASH digital delta-sigma modulator with odd initial condition

Multi-stAge noise SHaping (MASH) digital delta-sigma modulator (DDSM) with linear feedback shift register (LFSR) dither and odd initial condition is analyzed mathematically to investigate its periodic behavior. We derive the nonlinear equation of the quantization error in each stage to determine the corresponding sequence length. And five useful lemmas are introduced to help cope with the complicated calculation caused by the pseudo-random dither signal.

A Novel Architecture of Pseudorandom Dithered MASH Digital Delta-Sigma Modulator with Lower Spur

A Digital Delta Sigma Modulator (DDSM) is a Finite State Machine (FSM); it is implemented using finite precision arithmetic units and the number of available states is finite. The DDSM always produces a periodic output signal when the input is constant. This paper proposes a novel method of applying periodic dither to a DDSM in order to obtain minimized spurious tones. The effects of adding the pseudorandom dither signal in different stages within the proposed Multi-Stage noise Shaping (MASH) modulator are expressed in the equations, and the results are compared. We present results regarding the periodicity of the quantization noise produced by a MASH modulator with a constant input and a pseudorandom dither signal. The performance is confirmed mathematically, and by simulation.

Maximum Sequence Length MASH Digital Delta–Sigma Modulators

This paper presents a modified structure for the first-order digital delta-sigma modulator (DDSM) which yields the maximum sequence length (N) for all constant digital inputs and for all initial conditions. Using this structure, MultistAge noise-SHaping (MASH) DDSMs are developed which, for a constant input, always have a sequence length of Nl regardless of the initial conditions and input value, where N is the sequence length of each stage and l is the number of the first-order stages used in the MASH. The performance is confirmed mathematically, by simulation, and experimentally.