Codes Flashcards

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Questions and Answers

What is a Code Group?

A unique string of binary digits (correct)

A code with decimal weights

A type of error-detecting code

An ASCII representation

What is a Weighted Code?

A code in which corresponding decimal digits are easily determined by adding the weights associated with the 1's in the group's code.

What does 8421 Code represent?

A weighted code where the respective bits have decimal weights corresponding with 8421.

What are Self-Complementing Codes?

The complement of the code group corresponds to the 9's complement. Signup and view all the answers

Which of the following are examples of Nonweighted Decimal Codes?

2-out-of-5 Signup and view all the answers

Define Ecess-3 Code.

0011 + (8421 code#) Signup and view all the answers

What is the purpose of a 2-out-of-5 Code?

Two of the five bits must be 1's; it is error-detecting. Signup and view all the answers

What do Unit-Distance Codes ensure?

Only one bit changes between two successive integers being coded. Signup and view all the answers

What is Grey Code?

A binary numeral system where two successive values differ in only one bit. Signup and view all the answers

What are Characters in the context of coding?

Alphabetic symbols, numeric symbols, special symbols, certain control operations. Signup and view all the answers

What are Alphanumeric Codes?

Codes that are used to represent characters. Signup and view all the answers

What does ASCII stand for?

American Standard Code for Information Interchange. Signup and view all the answers

What is Unicode?

Unicode Standard provides encoding for English characters, foreign characters, punctuation, math symbols, technical symbols, geometric shapes, and dingbats. Signup and view all the answers

What is Error Detection?

Methods used to detect errors in transmission of binary information. Signup and view all the answers

What are Error Detecting Codes?

Codes that provide some level of error detection; do not necessarily detect all errors. Signup and view all the answers

What is a Parity Bit?

An additional bit appended to a transmission so that the number of 1's in a code group is even or odd. Signup and view all the answers

Explain Error Detecting Capability.

1 less than the minimum number of errors that a code cannot always detect. Signup and view all the answers

What does Distance mean between Code Groups?

The number of bits that must be changed in one code group to get to another. Signup and view all the answers

What is the formula for Error Detecting Capability (D)?

D = (minimum distance) - 1. Signup and view all the answers

Define Error Correction (C).

The relationship between the minimum distance of a code and its error-detecting and correcting capabilities. Signup and view all the answers

What is Hamming Code?

Single error-correcting code; code group contains coded bits and parity bits. Signup and view all the answers

Study Notes

Code Group Concepts

Code Group refers to a unique binary string composed of digits, essential for data representation.
A Weighted Code allows easy determination of decimal digits by summing weights associated with 1's in the code.

Specific Codes

8421 Code: A weighted code where binary digits correspond to decimal weights of 8, 4, 2, and 1.
Self-Complementing Codes: These codes have a complement that reflects the 9's complement system; an example includes the 2421 code.
Nonweighted Decimal Codes: Examples include Ecess-3 and 2-out-of-5 codes, which don’t rely on weights for interpretation.

Specialized Coding Systems

Ecess-3 Code: Created by adding the Ecess-3 adjustment to the standard 8421 code.
2-out-of-5 Code: Requires 2 bits to be 1's within a 5-bit group; effective for error detection, commonly used in USPS barcodes.

Coding Mechanisms

Unit-Distance Codes: These codes ensure that only one bit changes when transitioning between successive integers; Grey code is a primary example.
Grey Code Sequence: A binary code where two successive values differ by just one bit, facilitating error reduction in digital systems.

Character Representation

Characters can include alphabetic symbols, numeric symbols, special symbols, and control operations, essential for data encoding.
Alphanumeric Codes: These represent characters, combining both letters and numbers.

Standards for Encoding

ASCII: A 7-bit encoding standard, the American Standard Code for Information Interchange, widely used for text representation.
Unicode: A 16-bit encoding that supports a vast array of characters, including those from various languages and symbols.

Error Detection Mechanisms

Error Detection: Techniques utilized to identify errors in binary data transmission.
Error Detecting Codes: Codes designed for some level of error detection, though they don’t guarantee detection of all errors.
Parity Bit: An extra bit added to ensure an even or odd count of 1's based on parity rules, helping detect single and triple errors effectively.
Error Detecting Capability: Defined as one less than the minimum number of undetectable errors; for example, a parity bit can detect single errors but cannot detect cases where two bits flip.

Error Correction and Distance Concepts

Distance Between Code Groups: Measures the number of bit changes required to transform one code group into another.
Error Detecting Capability (D): Calculated by the formula D = (minimum distance) - 1, assisting in understanding the limits of error detection.
Error Correction (C): Relates minimum distance to its error-correcting abilities; governed by the equation C + D = M-1, where error correction capacity must not exceed error detection capacity.

Hamming Code

A code designed for single error correction, consisting of both coded bits and parity bits; follows a specific arrangement for coding data, which helps maintain integrity during transmission.

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Description

Test your knowledge of various coding systems with these flashcards. This quiz covers essential concepts like code groups, weighted codes, and self-complementing codes. Perfect for students and enthusiasts looking to solidify their understanding of coding fundamentals.