Electromagnetic Spectrum- Digital signal and transmission

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ELECTROMAGNETIC SPECTRUM RESEARCHDIGITAL signals and TRANSMISSIONS

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Contents A description of how the technology works, with reference to the electromagnetic spectrum. How this technology changed over time?The negative and positive impact of this technology on society

A description of how DIGITAL signals worksSignals are waves which carry information. Radio waves, microwaves, infrared and visible light are used as signal carriers (refer to Fig.2). Digital signal (shown in Fig.1) is one of the two types of signals. It consists of a chains of on and off pulses, which are coded using the binary number system; that is 1 for on and 0 for off. Time division multiplexing (TDM) is the technique used to transmit this signal. It starts off by breaking down the data into smaller amounts and then merged with an electromagnetic wave, known as the carrier wave, to be transferred under a single frequency. The information is obtained by the removal of the carrier wave and the signal is restored. Digital transmission is as the data over channels to a single point, as target (point-to-point) or a multipoint target (point-to-multipoint). Copper wires, optic fibers, wireless communication channels, storage media and computer buses are the variety of channels used.

Fig.1.This is a synchronized waveform of digital signal called clock signal. KEY: low voltage high voltage Raising edge: low-high voltage increase Failing edge: high-low voltage decrease

Fig.2.Carrier waves are used to transport the signal to places. Radio waves microwaves, infrared and visible light are used during that process.


How this technology changed over time?Digital signals have transformed how we watch TV to how we make phone calls from our mobile without wires like the landline. It is the, so called, new generation signal compared to analog signal. Analog signal is also a type of signal. It changes its amplitude and frequency constantly, unlike the digital signal which can only go on (1) or off (0). Digital signals can maintain the quality of the data they contain over long distance. Transitions, using digital signal, is simpler as the binary number system is easily read by computers. In our world today we use both, analog and digital signal transmissions, at the same time. An example of this would be recording equipment and microphones (Fig.3). Television (Fig.4) and radio broadcasters are changing from analog to digital transmissions not only because of the quality, but also as it could carry more data per second, than analog can.

Fig.4. These are the reasons why analog is replaced by digital signal when it comes to broadcasting.

Fig.3.This diagram shows how digital and analog signals are incorporated in microphones.ADC: Analog-to-Digital Converter DAC: Digital-to-Analog Converter


POSITIVENEGATIVEGood quality even for long distance transmissions and high quality imaging and audio (TV and Mobile phones) Even if there is interference through the transmission process, the signal is regereated to its original data. More data, per second, compared to analog signal. As the data is broken up to be quickly transferred thus more data could be crammed in. Digital cellular phones are good quality to converse without a cord restricting you from moving around. This is developed as digital signal could be transferred through air. This data (signal) could easily be hackedIt is easy to decode digital because of the two digit binary number system used for coding. More expensive than analog, as it is incorporated with the latest technology. It is to makes the latest phones and technology more luxurious, thus more people will buy it. Analog signal still has a richer voice quality than digital. As it is the original wave getting transferred without any alteration.

The negative and positive impact of this technology on society

THANKS FOR WATCHINGBy: NandithaMN


BIBLIOGRAPHY https://en.wikipedia.org/wiki/Data_transmissionhttps://in.answers.yahoo.com/question/index?qid=20150305083710AAPjb8Ehttps://learn.sparkfun.com/tutorials/analog-vs-digitalhttp://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-450-principles-of-digital-communications-i-fall-2006/lecture-notes/book_1.pdfhttp://telecom.hellodirect.com/docs/Tutorials/AnalogVsDigital.1.051501.asp https://www.youtube.com/watch?v=XCu6L4kQF3khttp://electronics.howstuffworks.com/digital-versus-analog1.htm

Science

Electromagnetic Spectrum- Digital signal and transmission