# Lesson 20 — Analog-to-Digital Conversion

Sampling and Nyquist, aliasing, quantization, resolution, the digital output value and its error, and what a recording costs in bits.

**Objectives covered** - **2.5** — I can calculate the ADC sampling rate, voltage resolution, and digital output based on a given input voltage and the ADC's operational parameters, and determine the number of bits a required resolution demands.
Reading

Analog-to-Digital Conversion

The course reading for Objective 2.5.

 Flashcards

Review deck

Key terms, equations, and ideas from this lesson, in a self-test deck.

 Slides

Lesson 20 deck

The slides used in class, as a PDF.

 Practice Problems

Work these before the quiz

Ungraded problems with answers, on the downloads page.

 Demo ↗

ADC Demo

Analog-to-digital conversion with adjustable bit depth and rate.
## Demos **Aliasing in the wild** The camera samples the rotor at almost exactly its rotation rate, so the blades alias down to a near-zero apparent frequency and the rotor looks frozen. Same effect as sampling below Nyquist. **Hearing quantization** The same passage at decreasing bit depth. As resolution drops the quantization error grows until you can hear it as noise on the signal.