Detection of Errors in Digital Systems

In Detection of Errors in Digital Systems, you'll learn ...

• How errors are introduced in data transmission and retrieval
• The basic approach of error detection and correction
• The purpose and function of a parity bit
• Checksum and cyclic redundancy check (CRC) methods
• How a cryptographic hash function works and when it should be employed

Overview

Credit: 2 PDH

Length: 11 pages

We are exposed to a lot of information every day, from viewing content on a website on the Internet to listening to a song on our smart phone. This information (or data) is constantly stored, transmitted and processed. It is important that the data is correct or relatively error-free. Some amount of error is acceptable, depending on the application. For example, a few bit errors in a music data file in an MP3 format are acceptable, but a few bit errors in the data being transferred to the flight controls of a rocket could be catastrophic.

Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. When Claude Shannon developed information theory in 1948, thus ushering in the information age, he introduced the concept of entropy to information. This entropy or shortage of information in a message is what gives rise to errors in the data. Most communication systems and data storage and processing systems are unreliable to some degree, which means that errors may be introduced in the communications channel or while retrieving data from a memory device. These errors must be controlled.

The purpose of this course is to describe four different error detection techniques and to discuss the advantages and disadvantages of each. This course describes the parity check method as well as the checksum and cyclic redundancy check (CRC) methods. It describes hash functions and when they should be employed. The course also briefly discusses error correction techniques.