Analog Signals

PWM (Pulse Width Modulation)

We use it for things like motor control. Digital approximation of an analogue signal.

Output voltage is proportional to width. We need to use timers for this.

Either we count up and count down which makes a triangle (equilateral - phase correct) or a harsh triangle (count up and drop to 0).

We have to sample at least twice the max frequency of the signal.

A/D converters

  • Conversion Time; Time required to convert a signal
  • Resolution; smallest input signal that we can convert
  • Accuracy; percentage of how accurate the conversion is
  • Linearity;
  • Missing Codes;
  • Aperture Time;