Data Transmission
The purpose of this report is to describe some common data transmission terminology. This paper will discuss various data transmission (communication) protocols and how they are used in data communication.
Synchronous and Asynchronous:
Asynchronous serial transmission is a technique used in serial RS232 communication. The data is framed by a series of control bits known as the start bit, stop bit(s), parity bits and error checking bits. A transmit clock signal is used to clock the data over the transmission line to the receiving end. At the receiver, a clock signal, known as the receive clock, which corresponds to the transmit clock is used to decode the transmitted data back to the original by stripping off the control bits.
Synchronous transmission sends data packets, in contrast to Asynchronous transmission, which sends data one bit at a time. The data is surrounded by start and end frames. The start frame tells the receiver to synchronize its internal clock and to expect the incoming packets. The end frame marks the end of the packet.
Low speed data transmission uses asynchronous transmission. Because asynchronous transmission does not include error checking, it is not very efficient. Synchronous transmission, on the other hand is very efficient. Data is transmitted in blocks. Synchronous communication is well suited for high speed data transmission. The protocol has error checking capabilities.
Analog and Digital:
Analog signals represent continuously changing signal such as sound wave emitted from a speaker or an alternating current (sine wave) traveling on a wire. Digital signal, on the other hand is a digital representation of an analog signal, it is either off or on.
AM - Amplitude modulation and FM Frequency modulations are means by which use to transmit analog signal. DM Digital modulation is used to transmit digital signal (Analog vs Digital Transmission, 2005)
X on and X off:
X on / X off is a handshaking control signal used to control the flow of data communication. It works like this. A printer connect locally to computer use the X off control signal to notify the computer that the print buffer is full and should stop sending data. When the printer is ready for more data, the X on signal is send to signal the computer to resume data transfer.
Simplex and Duplex:
Simplex transmission is used transmit data in one direction only. It is like a one-way street for data.
Duplex transmission means that data is transmitted in both directions.
After compression, the structure data, audio and video must be multiplexed. A number of compressed TV signals are combined by a multiplexer and put unto a shared transition medium. This is done by one of the two possible kinds of multiplexers that result in either a transport or a program stream, which is suited for secure transmission paths since it can contain large amounts of information. In addition multiplexing can be done using various methods. Time division multiplexing allocates a distinct time interval for each channel in a set; with the help of synchronization and a fixed interval order the channels take turns using the common line.
Sending data through the internet efficiently has always posed many problems. The two major technologies used, Ethernet and Asynchronous Transfer Mode (ATM), have done an admirable job of porting data, voice and video from one point to another. However, they both fall short in differing areas; neither has been able to present the "complete" package to become the single, dominant player in the internet market. They both have dominant areas they cover. Ethernet has dominated the LAN side, while ATM covers the WAN (backbone). This paper will compare the two technologies and determine which has a hand-up in the data trafficking world.
Dense wavelength division multiplexing (DWDM) is a technology that puts data from different sources together on an optical fiber, with each signal carried at the same time on its own separate light wavelength. Using DWDM, up to 80 (and theoretically more) separate wavelengths or channels of data can be multiplexed into a light stream transmitted on a single optical fiber. Each channel carries a time division multiplexed (TDM) signal. In a system with each channel carrying 2.5 Gbps (billion bits per second), up to 200 billion bits can be delivered a second by the optical fiber. DWDM is also sometimes called wave division multiplexing (WDM). Since each channel is demultiplexed at the end of the transmission back into the original source, different data formats being transmitted at different data rates can be transmitted together. Specifically, Internet (IP) data, Synchronous Optical Network data (SONET), and asynchronous transfer mode (ATM) data can all be traveling at the same time within the optical fiber.
This digital data takes the form of binary numbers, physically transferred by sending zero volts for zero or off and plus five volts for one or on. Certain binary numbers convey certain types of information, for example a certain binary number will tell the device that a note on a keyboard has been pressed. This is called a note on event and the
Few may thing that analog is better than digital, but others may think otherwise. Analog shows everything changing while digital only shows the exact time. Digital is an easier way of doing things and analog could be easy for some people who know how to read an analog clock. Digital takes some sound waves that they have and it records it. While analog may record all of the waves digital only records the waves that are needed because the waves that it is getting my be the same waves so it just records some of the waves.
In telecommunication signaling within a network or between networks, synchronous signals are those that occur at the same clock rate when all clocks are based on a single reference clock. Synchronous communication requires that each end of an exchange of communication respond in turn without initiating a new communication.
Digital signals convert regular signals into strings of ones and zeros, which is much more efficient than analog signals. Broadcasters can maximize their use of channel space because digital signals carry significantly more information than analog signals. Several digital programs and services can be sent in the space occupied by a single analog channel. The result of this is that the consumer is provided with more channel choices(FCC).
When you think of digital signal processing, what comes to mind? Well you may think digital signals, so cell-phones? What about radio’s or even satellite television? The answer is yes, all these are correct, but there is a broader impact of digital signal processing that goes beyond these everyday items. Digital signal has been around for about 5 decades, starting back in the early 1970’s [4]. Analog has
In recent years, network coding [1], [2] has been considered as an auspicious information network paradigm for augmenting the throughput of multiple unicast networks [5]. The pioneering researches of network coding were undertaken by R. Ahlswede, N. Cai, S.-Y.R. Li and R.W. Yeung. Their discovery, which was first introduced in [1][2], are considered to be the crucial breakthrough in modern information theory and the time of its appearance, is recognized as the beginning of a new theory-Network Coding theory. In these elegant, succinct articles, within the purview of rigorous mathematics, the glimmering of an optimal network protocol for multiple unicast network was introduced in which the key idea is considering digital information as wave [riis].
The most important component of any system that stores analog sound waves as digital data is the analog-to-digital converter (ADC). Analog signals by nature have no defined behavior, but digital signals are rooted in the concept of patterns and numeric, mathematical representation [3]. The conversion from an analog signal to a digital signal is therefore the part of our system that will most determine the quality of the digital data that we obtain from our analog signal [3]. Preferably, digital audio should have high fidelity and perfect reproducibility. High fidelity means that our system is capable of accurately reproducing the digitally recorded analog signal without being noticeably different to the or...
An audio signal is a demonstration of sound typically as an electrical voltage. The audio frequencies of the audio signals have in the range of roughly 20 to 20,000 Hz. Audio signals may be synthesized or can be originated at a transducer like in a microphone, loudspeakers, musical instruments, pickup convert an electrical audio signal in the form of sound. Digital representations of audio signals exist in number of formats. Audio signals may be characterized by parameters such as their bandwidth, power level in decibels (dB), and voltage level.
Asynchronous Transmission: The asynchronous signaling methods use only 1 signal. The receiver uses changes on that signal to figure out the rate and timing of the transmitter, and then synchronizes a clock to the proper timing with the transmission rate. A pulse from the local clock indicates when another bit is ready. Asynchronous transmission is a slower but less expensive and effective for low-speed data communication.
One of the latest advancements in wireless data. It is used in GSM (Global System for Mobile Communications) for transferring data in packets.
Explain how the two important transport protocols deliver messages on behalf of the application and discuss the differences between them
People in the present society have turned from the use of the old means of communication to the more advanced and technological ways of communicating. Technology has made it easier for people to communicate in a faster, efficient, and cost saving means through the introduction of the communication channels. The world has turned out to be the centre for technology with different technologies emerging daily as the people continue to develop from time to time to cope with the growing technology. The benefits of adopting the communication technology are explained in this article which shows why people do not function without technology.