This work investigates the commonly used Asynchronous Sigma Delta Modulator which consists of a schmitttrigger and a continuous time loop filter. A detailed analysis is presented to accurately predict the distortion of such modulators. The extracted expressions are compared with simulation results and they illustrate an excellent match. The results are also compared with a previous work by Roza...

An eighth-order switched-current bandpass delta-sigma modulator is described. Simulations indicate that our 1.2pm CMOS implementation will achieve a S N R of 90dB in the band 10 MHzk150 KHz when clocked at 40 MHz. The modulator makes use of a switched-current resonator based on the N-path technique and the resonator employs regulated-cascode current-copiers to simultaneously achieve high speed ...

Extending an existing architecture for delta-sigma conversion of vector inputs, we suggest spectrally shaping quantization noise jointly in temporal and spatial frequency domains with delta-sigma modulation, and we examine the application of the idea to wideband antenna or acoustic arrays and to halftoning of video imagery.

In this paper we present a method for stability analysis of high order Sigma-Delta modulators. The method is based on a parallel decomposition of the modulator. Using this presentation the general N-th order modulator could be considered as made up of N first order modulators, which interact only through the quantizer function. The decomposition helps us to extract the stability conditions of t...

An important factor affecting the performance of modulators is their tone behavior. A recent approach to alleviate the tone problem consists of moving the open-loop poles outside the unit circle. In this paper, we determine the frequency location of two dominant tones as a function of pole-location, and discuss the effect of pole location on the relative amplitude of low-frequency tones. Audio ...

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In this paper we investigate the relationship between the pulse-coded signal representation found in biological neurons and signals represented by first-order delta-sigma bit-streams. We show that a first-order delta-sigma bit-stream is a digital equivalent to a pulse-coded neural signal. By increasing the clock frequency, a delta-sigma bit-stream can approach a pulse-coded representation with ...

We examine a model for a bandpass Σ∆ modulator introduced by Feely and co-workers. This is shown to have the dynamics of a piecewise isometry of a union of convex polygons on the plane by an appropriate transformation of the linearised parts into normal form. Using these we show that the periodically coded regions form a packing of the phase space by circles and we link this system to a number ...