Analog and Digital Technologies
To understand the technologies of analog and digital conversions we must first understand what analog and digital transmissions are. Analog transmissions are a continuous variable in amplitude and frequency. The frequency band that they operate over defines analog circuits. People generally produce a bandwidth of 9,900Hz with frequencies in the range of 100Hz to 10,000Hz. Speech that falls between 250Hz and 3,400Hz is considered intelligible speech and therefore the network circuits use bandwidth-limiting filters designed to filter out all frequencies above 4,000Hz. For these reasons, analog circuits are low-speed data communications, with a maximum data rate of 33.6Kps when analog loops are at both ends of the circuit.
Digital transmissions are very different from analog transmission. A digital transmission is a series of pulses that are ones or zeroes and these ones and zeroes make up combinations to create characters in characters sets. The way the signal is carried depends on whether the network is electrical or optical. In an electrical network, the ones and zeroes are either high voltage or low voltage. With an optical network, it is either the presents of light or no light.
Communications today are transmitted over a mix of digital and analog networks. Conversion is necessary for data to be transmitted across the various networks. Codecs are the devices that convert the transmissions from analog to digital. Modems are other devices that infuse digital signal onto transmission conveniences. Modems control the variables of electromagnetic wave to determine the ones and zeroes. Conversions are weak points in the network and errors and distortions can occur at these points.
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...s Cited
Alturayef, M., Rodriguez, D.(2007).ADSL Technology, Retrieved May 6, 2014 from http://ecee.colorado.edu/~ecen4242/adsl/adsltechnology.htm
Ash, J. D. (2007, December). Next generation SDH: Does it have a role in future packet-based wireline networks? Journal of Telecommunications Management, 1(2), 189.
Bhatia, A (2007) 802.11 Retrieved May 7, 2014, from http://it.toolbox.com/wiki/index.php/802.11
Diffen. (2014, May). AM vs FM. Retrieved from http://www.diffen.com/difference/AM_vs_FM
Digital Transmission Hierachies. (2004). Retrieved from http://telecom.tbi.net/dighier1.html
Poole, I. (2014, May). What is QAM- Quadrature Amplitude Modulation. Retrieved from Http://radio-electronics.com/info/rf-technology-design/pm-phase-modulation/what-is-qam-quadrature-amplitude-modulation-tutorial.php
T-carrier. (2014). Retrieved from http://en.wikipedia.org/wiki/T-carrier
COMP09022 Network Design BSc COMPUTER NETWORKING COMP09022 ICMPv6 Prepared by B00270675 13-03- 2015 WORD COUNT (0000) TABLE OF CONTENTS TITLE PAGE……………………………………………... 1 TABLE OF CONTENTS………………………………….. 2 INTRODUCTION TO THE REPORT……………………. 3 TABLE OF FEATURES.......................................................4
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.
Communication between people is done in two ways: verbally and nonverbally. Those are layman terms. The language of verbal communication is described as digital code, whereas nonverbal communication is called analog code. The main difference that you could probably presume is that verbal communication involves a language, or better yet, spoken words. Inversely, nonverbal communication integrates the use of symbols or gestures to communicate an idea or feeling.
Recording technology wasn’t always a digital process. Before the 1970s, all recordings depended on capturing a physical analogue sound with microphones. This was done on either tape or disk. Analogue recordings lacked the sonic integrity that the 21st century demanded; it was becoming increasingly problematic and expensive in reducing noise and distortion that plagued analogue recordings. As a result, audio researchers began to study digital conversion techniques. They discovered that digitizing an electrical audio signal consisted of sampling the audio wave thousands of times a second, measuring the peak amplitude of each sample, and then assigning one of a limited number of binary values to each.
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
The uses of Digital Signal Processing in communications has become so large scale that nearly any form of analog communication is considered obsolete. Today, nearly any form of communication used, aside from verbal communication, relates to Digital Signal Processing. Some of the more prominent uses for DSP in communications are; local area networks, cell pho...
We can use Public Switched Telephone Network (PSTN) as an example to explain the relationship between the data rates of the inputs and output of a TDM. Hanrahan (2005) indicates that there exists the need to transmit multiple subscribers’ calls along the same transmission medium. To meet the requirement, TDM is used because TDM allows switches to create channels within a transmission stream. If an input is a standard DS0 voice signal has a data bit rate of 64 Kbit/s, TDM takes frames of the voice signals and multiplexes them into a TDM frame which runs at a higher bandwidth. In other words, if the TDM frame consists of n voice frames, the bandwidth will be n*64 Kbit/s.
ATM is geared toward high speed voice and video transmission, much like a telephone network. It uses a cell-switching and multiplexing technology. The data (this refers to data, voice and video) is transferred between two points on a dedicated circuit in 53 byte cells. Each cell is the exact same size, no matter what data is being sent. The cells consist of 5 bits of header information and 48 bits of actual data. Using a smaller, consistent cell size means there's less delay between when each cell processes at the other end. Using dedicated circuits via virtual circuits ensures there is no interruption in the data transfer. This is extremely important to voice and video transmissions, because they are highly intolerant to data delays. This improves the Quality of Service (QoS) and speed of transfer, which can be between 25 Mbps to 622 Mbps.
Analog communication employs continuous transmission of an electromagnetic wave form that varies in frequency and amplitude.
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).
In the Using the pulse modulation technique, the analog signal is converted into the digital signal. The process of quantization and companding of a signal is carried on the spreadsheets. To attain a clear signal to quantization noise ratio, the number of samples should be increased. By increasing the sampling depth, the quantization error can be minimized. By companding process, the quantization noise and distortion levels can be minimized. Companding improves response for low amplitude signals.
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.
Hollows, P 2002, 'Essentials of a smooth-running network', Communications News, vol. 39, no. 7, p. 16.
According to Pew Research Center's Journalism Project, the overall drop in newspaper circulation began in 1989 and has been at a gradual decline of 1% a year since (Pew Research Center's Journalism Project, 2007). 1989 is also the year of the birth of the World Wide Web(Home.web.cern.ch, 2014).
Over time the different means of receiving the internet have changed several years ago, a phone line would proved a slow connection to the internet, but would not be useful when storing and...