CP/PC364 Data Communications & Networks Laboratory

A/D Conversion

Overview

Digital transmission of analog data, (such as sound and video), requires analog input signals to be converted to digital signals for processing. Once received, the signals then have to be converted to back analog. These conversions are done by analog to digital (A/D) and digital to analog (D/A) converters, respectively. Although you could construct these converters from discrete components, integrated circuits specifically designed for these purposes are usually used.

Objectives

The objectives for this lab are:

• to test the A/D of the Arduino for proper operation
• to investigate the effects of the A/D conversion process

Equipment

• Arduino
• bench supply, oscilloscope, function generator
• breadboard, debugger board, resistors, capacitors

Task

1. Wire up the DC supply to the analog input of the Arduino.
2. Run or modify an appropriate sketch to display the analog input value on the LCD. Display both the digital value and the corresponding analog input voltage.
   Note: It will make you life easier in the future (as well as being good programming practice) to use a variable for the reference voltage rather than hard-coding it into your conversion formula.
   Demonstrate your circuit to the lab supervisor.