ADC

An Analog to Digital Converter (ADC) is a type of circut that converts an analog voltage signal to a digital one, based upon some range of voltages. This is also known as sampling.

Overview

Parallel

  1. Analog voltage is converted to a codeword, by running the voltage through a series of comparators, each tied to a different voltage
  2. The series of codewords are put through a series of logic gates that convert the code words to a n-bit value, ranging from 0V to VREF

This is a very fast way to implement a ADC, however for a n-bit resolution it requires 2^n - 1 comparators, and 2N resistors (for voltage dividers) to convert the signal

Counting

  1. Compare the analog input voltage to an output from a DAC
  2. Each time a comparison fails, increment a counter
  3. When the DAC voltage is larger than the analog voltage, we have found the correct value