In an ADC chain, what does the encoder do?

In an ADC chain, what does the encoder do?

• A. A Converts quantized levels into a digital word
• B. B Converts analog input directly into a digital word without quantization
• C. C Applies a reconstruction filter to the samples
• D. D Converts quantized levels into a digital word

Answer: (D)

In an ADC chain, the encoding stage takes the discrete level chosen by the quantizer and turns it into a binary digital word. After sampling and quantization, you have a finite set of level indices (for an n‑bit ADC there are 2^n possible levels). The encoder assigns a binary code to each of these levels, producing the digital representation that can be stored, transmitted, or processed by digital circuitry. This encoding is essential because it converts the quantized level into a format usable by digital systems. The other ideas don’t fit this stage: you can’t go from analog input directly to a digital word without quantization in this context—the quantizer must reduce the signal to a finite set of levels first. And applying a reconstruction filter to the samples is a task associated with smoothing the signal after digital-to-analog conversion, not the encoding step in the ADC.

In an ADC chain, the encoding stage takes the discrete level chosen by the quantizer and turns it into a binary digital word. After sampling and quantization, you have a finite set of level indices (for an n‑bit ADC there are 2^n possible levels). The encoder assigns a binary code to each of these levels, producing the digital representation that can be stored, transmitted, or processed by digital circuitry. This encoding is essential because it converts the quantized level into a format usable by digital systems.

The other ideas don’t fit this stage: you can’t go from analog input directly to a digital word without quantization in this context—the quantizer must reduce the signal to a finite set of levels first. And applying a reconstruction filter to the samples is a task associated with smoothing the signal after digital-to-analog conversion, not the encoding step in the ADC.