Methods for creating analog waveforms

A project log for DaFunc

Simple pocket sized function generator

gannongannon 12/05/2014 at 03:130 Comments

There are two main methods of creating an analog waveform using a digital one. Due to various limitations of the Trinket Pro hardware the pros/cons are listed below.

  1. PWM driven Low Pass Filter
    1. Maximum analog waveform frequency between 3-6khz
    2. Only uses a single pin (with good fidelity with proper filter design)
  2. R2R DAC
    1. Maximum theoretical analog waveform frequency of ~2Mhz
    2. Uses mutliple pins (more for better fidelity)
Due to the fact that method 1 uses only a single pin the function generator could theoretically contain 8 analog channels whereas you would be lucky to be able to get 2 channels from method 2.

Given enough time I plan on using a mix of both methods 1 and 2, where I have a single high speed output line and multiple low speed outputs.