Engineering
How a Sigma-Delta Analog-to-Digital Converter Achieves High Resolution
Quick fact
A sigma-delta ADC can achieve 24-bit resolution using only a 1-bit quantizer (a comparator) by oversampling and shaping the quantization noise so that most of it falls outside the signal band, leaving an almost noise-free signal.
Why this is interesting
You might think that to get a 24-bit digital reading of an analog signal you need a circuit that makes 16 million distinct decisions. But the ADC in your smartphone's microphone achieves that precision using a single bit and a lot of clever repetition—how?