# Which of the following is an example of oversampling ADC architecture?

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Which of the following is an example of oversampling ADC architecture?

1. Sigma delta
2. Successive approximation
3. Integrator
4. Flash

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Correct Answer - Option 1 : Sigma delta

Explanation:

• An analog signal first undergoes the process of sampling before it is applied to ADC for conversion into a digital signal.
• Oversampling is a process in which an analog signal is sampled at a sampling frequency that is much greater than the Nyquist rate.
• A Sigma-Delta ADC is an example of an ADC that employs oversampling.
• It is the same as “Delta modulation”. That is 1 sample is represented with 1 bit.
• In oversampling correlation increases and Quantization noise decreases.

To reduce the Quantization noise two things are done.

Oversampling and Noise shaping.

Oversampling is:

fs' = K × fs , ( K > 1)

The transfer function for Noise shaping is given by

$H\left( s \right) = \frac{1}{{s + 1}}{V_{in}} + \frac{s}{{s + 1}}Q$

$\frac{1}{s + 1}$ : Acts as LPF for Vin and as an HPF for Quantization noise.

Q: Quantization noise