30-06-2012, 02:31 PM
Implementation of Floating Point Encoder and Decoder Using VHDL
FLOATING POINT ENCODER AND DECODER DESIGN USING VHDL.docx (Size: 176.2 KB / Downloads: 33)
ABSTRACT
In communications Data compression which enables devices to transmit or store the same amount of data in fewer bits. Our main challenge is to provide an efficient Data compression technique which is easy to design and implement with good accuracy, floating point encoding and decoding technique fulfills this requirement. Data compression is also widely used in backup utilities, spreadsheet applications, and database management.
CHAPTER 1
INTRODUCTION
FLOATING POINT ENCODING AND DECODING is a type of modulation technique in which the digital data is encoded from 8-bit to 5 bits and transmitted. At the receiving end 5bit data is decoded from 5-bit to 8-bit.In this compression and expansion we use two important words namely mantissa and exponent which are discussed later in this context. This technique is easy to implement and design.
1.1 OBJECTIVE
Our main objective is to design an FLOATING POINT encoder and decoder using VHDL for providing efficient voice and data transmission using less bandwidth. For this we used the concept of Mantissa and Exponent representation. Due to this the band width can be reduced.
1.2 ORGANIZATION OF THESIS
This thesis is divided into six chapters.
Chapter1 describes the introduction of FLOATING POINT ENCODING AND DECODING and overview of our project.
Chapter2 describes the introduction of Data compression techniques and encoding and decodig.
Chapter3 describes the Floating point encoding and decoding working principle along with its functioning. Chapter4 gives the fundamental idea about the sub-modules and their implementation..
Chapter 5 shows the simulation results of the project.
Chapter 6 shows conclusions and references.
CHAPTER 2
DATA COMPRESSION TECHNICQUES
2.1 INTRODUCTION
Data compression is also widely used in backup utilities, spreadsheet applications, and database management systems. Certain types of data, such as bit-mapped graphics, can be compressed to a small fraction of their normal size.
Data compression is particularly useful in communications because it enables devices to transmit store the same amount of data in fewer bits. There are a variety of data compression techniques, but only a few have been standardized. The CCITT has standard data compression technique for transmitting faxes a compression standard for data communications through modems .In addition, there are file compression formats, such as ARC and ZIP.
IEEE Standard 754 floating point is the most common representation today for real numbers on computers, including Intel-based PC's, Macintoshes, and most Unix platforms. This article gives a brief overview of IEEE floating point and its representation.
What Are Floating Point Numbers?
IEEE floating point numbers have two basic components: exponent, and mantissa. The mantissa is composed of the fraction and an implicit leading digit (explained below). The exponent base (2) is implicit and need not be stored.
The Exponent
The exponent field needs to represent both positive and negative exponents. To do this, a bias is added to the actual exponent in order to get the stored exponent. For IEEE single-precision floats, this value is 127. Thus, an exponent of zero means that 127 are stored in the exponent field. A stored value of 200 indicates an exponent of (200-127), or 73.
The Mantissa
The mantissa, also known as the Significant, represents the precision bits of the number. It is composed of an implicit leading bit and the fraction bits.
2.2 ENCODING AND DECODING
In computers, encoding is the process of putting a sequence of characters (letters, numbers, punctuation, and certain symbols) into a specialized format for efficient transmission or storage. Decoding is the opposite process -- the conversion of an encoded format back into the original sequence of characters. Encoding and decoding are used in data communications, networking, and storage. The term is especially applicable to radio (wireless) communications systems.
The code used by most computers for text files is known as ASCII (American Standard Code for Information Interchange, pronounced ASK-ee). ASCII can depict uppercase and lowercase alphabetic characters, numerals, punctuation marks, and Common symbols. Other commonly-used codes include Unicode, Bin Hex, Uuencode, and MIME. In data communications, Manchester encoding is a special form of encoding in which the binary digits (bits) represent the transitions between high and low logic states. In radio communications, numerous encoding and decoding methods exist, some of which are used only by specialized groups of people (amateur radio operators, for example). The oldest code of all, originally employed in the landline telegraph during the 19th century, is the Morse code.
The terms encoding and decoding are often used in reference to the processes of analog-to-digital conversion and digital-to-analog conversion. In this sense, these terms can apply to any form of data, including text, images, audio, video, multimedia, computer programs, or signals in sensors, telemetry, and control systems. Encoding should not be confused with encryption, a process in which data is deliberately altered so as to conceal its content. Encryption can be done without changing the particular code that the content is in, and encoding can be done without deliberately concealing the content.