Questions tagged [delta-sigma]

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Adaptive Delta Modulation: Logic for step size control at receiver

I read that in adaptive delta modulation, we have a block for step size control (diagram below) which takes into account the one bit quantizer output in a feedback loop and modulates it, the intent ...
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1answer
119 views

How to implement filter poles in noise shaping for ΔΣ modulator?

I am currently stuck trying to implement filter poles to stabilize a ΔΣ modulator. What I think I know is: a noise shaping filter with only complex zeros along the unit circle destabilizes a 1 bit ΔΣ ...
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1answer
59 views

What is the difference between the spectra of white Gaussian noise and of a Dirac impulse?

Perhaps it is a basic question, but can anyone explain the difference between the spectra (or power spectral density) of white Gaussian noise and a Dirac delta? They are both constant over the whole ...
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1answer
47 views

Remove noise introduced while converting a Delta-Sigma Modulated (DSM) signal into a pulse-code modulated (PCM) signal?

I'm writing a tool that converts a dsdiff audio file (dsd64) into a flac audio file (DSM -> PCM). The project is both a programming exercise and a signal processing exercise; I'm learning a lot ...
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1answer
171 views

How does the world's simplest sigma-delta DAC work?

I have run into a simple delta-sigma (supposedly, where is the delta part?) DAC implementation utilizing an accumulator and then using the overflow bit as a modulated 1-bit output. From https://www....
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3answers
229 views

What is the Effect of Multiplying a Function by the Unit Impulse Function in the Frequency Domain?

I know about the the shifting property of the impulse function in the time domain as can be seen in equation $(1)$. $$ \int_{-\infty}^{\infty} f(x)\delta(x - a)dx = f(a)\tag{1} $$ But what is the ...
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1answer
96 views

why does my integrator perform noise shaping?

I am designing (in matlab) a simple system with a DC signal at 0 Hz and some added noise. I am performing a differentiation of the signal (by simply subtracting the last values from each other), next ...
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1answer
195 views

Is there a relation between the dead zone of sigma delta modulator and filter order?

This question refers to the link https://pure.tue.nl/ws/portalfiles/portal/1546321/521243.pdf. In chapter 4 it discusses the topic of dead zone, which appears in the delta sigma modulator. Dead zone ...
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1answer
77 views

Is there any difference in Implementing sigma delta modulator using filters and state space model in FPGA?

Sigma delta modulation is extensively used in quantization to reduce quantization noise. In the literature one can see different architecture for example python-deltasigma to implement a modulator. ...
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1answer
346 views

How to plot noise shaped spectrum of First order Incremental Sigma Delta ADC's output?

A little background: This question is about viewing the output spectrum of incremental delta sigma modulators (IDSM). IDSM is a subcategory of general delta sigma modulators where the integrators are ...
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1answer
521 views

Why use a 1-bit ADC in a Sigma Delta Modulator?

When looking at the discrete model of a Sigma-Delta Modulator as shown below, we can see that the quantizer is modelled as a white-noise source $e[n]$. From this model, we can derive the noise shaping ...
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1answer
1k views

How to implement a $1$-bit quantizer in Simulink?

I am trying to implement a delta-sigma modulator block diagram in Matlab Simulink but can't find a $1$-bit quantizer (which is required in the modulator) anywhere. Could anyone please tell me how to ...
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1answer
484 views

Power spectral density of sigma-delta modulator

I am simulating a 3rd order SDM and I want to plot the PSD of the output. As you may know, the output is a sequence of pulses ranging from -3 to +4. The number of samples is $N$. The way I ...
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1answer
172 views

Does delta-sigma ADC also reduce Gaussian noise on input signal to ADC or just quantization noise?

The motive for posing this questions arises from a difference of analysis between a colleague an myself. Our general environment is in the construction of an analog front-end which takes in signals ...
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0answers
56 views

Sigma Delta Sampling

I am using a Sigma Delta ADC and really understood the working of it I need to sample a signal at 8.5 Mhz. The SD ADC has a Demodulator and decimating FIR filter The Oversampling ratio options are 32/...
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0answers
220 views

Anti-aliasing requirements for a Muxed Sigma-Delta Converter

It seems to be reasonably well accepted that Sigma-Delta ADCs have much looser requirements for the anti-aliasing filter due to both the noise shaping and high modulation frequency. However, it seems ...
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3answers
1k views

How would sigma-delta modulation work in software?

I've recently come across this YouTube video that shows a PCM stream being played back via the 1-bit internal "PC Speaker", and after hours of googling I've come to think this is done via Sigma-Delta ...
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1answer
282 views

How does Delta-Sigma Modulation convert a 1-bit signal to higher resolution signal?

I've looked at various resources about Delta-Sigma modulators, and I find them fascinating. However, I'm confused on a particular point and and am looking for an explanation. In my understanding, ...