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

1. What is the resolution of an ADC with Sigma-Delta structure?
2. How does a Sigma-Delta modulator work?
3. What is the main advantage of Sigma-Delta architecture?
4. Why oversampling is used in Sigma-Delta ADC?

What is the resolution of an ADC with Sigma-Delta structure?

Sigma-delta ADCs typically have 16 to 24-bit resolution, with a usable input signal frequency range of a few Hz to a few kHz. There are some 16-bit sigma-delta ADCs with conversion rates up to 1 MSPS.

How does a Sigma-Delta modulator work?

In delta-sigma modulation, accuracy of the modulation is improved by passing the digital output through a 1-bit DAC and adding (sigma) the resulting analog signal to the input signal (the signal before delta modulation), thereby reducing the error introduced by the delta modulation.

What is the main advantage of Sigma-Delta architecture?

Delta-sigma ADCs implement oversampling, decimation filtering, and quantization noise shaping to achieve high resolution and excellent antialiasing filtering.

Why oversampling is used in Sigma-Delta ADC?

Oversampling helps avoid aliasing, improves resolution, and reduces noise. The sigma-delta ADC oversamples the desired signal by a large factor and filters the desired signal band. Unlike the Nyquist rate converters, in oversampled converters each output is obtained from a sequence of coarsely quantized input samples.