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.
Analog-to-Digital Conversion
The course reading for Objective 2.5.
FlashcardsReview deck
Key terms, equations, and ideas from this lesson, in a self-test deck.
SlidesLesson 20 deck
The slides used in class, as a PDF.
Practice ProblemsWork 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.