= 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
   - ie. VREF = 5V, 10-bit ADC, each step is 5/(2^10) = 4.9mV

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