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Sam Parrotte Joshua Young Jason Hernandez November 19 th 2013 1
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1.What is Digital Modulation? 2.Why use it? 3.How is it related to Embedded Systems? 4.Sample Forms of Digital Modulation 5.Ethernet 2
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Process of using an analog carrier signal to contain discrete information Digital-to-analog modulation of data Analog-to-digital demodulation of carrier Analog Modulation vs. Digital Modulation Similar: Manipulates a carrier wave to transmit data Different: Digital has a finite number of states the carrier will be in => often known as keying 3 http://www.mathworks.com/matlabcentral/fx_files/30580/1/ASK.jpg
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http://upload.wikimedia.org/wikipedia/commons/a/a4 /Amfm3-en-de.gif http://electronicdesign.com/communications/understanding -modern-digital-modulation-techniques 4
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5 http://www.ghielectronics.com/img/www/products/381-0_small.jpg Demodulation techniques offer beneficial recovery abilities Multiple parties share mediums to communicate information Commonly shared mediums: o Cable o Air
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http://www.founten.com/wp- content/uploads/2012/06/WifiSpectrumComparisonFounten.png http://pharos.ece.utexas.edu/wiki/images/thumb/4/40/XBee-pro- series1.jpg/300px-XBee-pro-series1.jpg Xbee Spectrum 6
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http://www.siemon.com/us/white_papers/images/05-02-17_wifi_why_for_us-freq-allocations-chart_big.jpg 7
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Router Access Send information to a server Interact with Wifi devices Direct communication between devices When sending high data rates When multiple devices share a medium Commercial RF Product Cant use predesigned boards Must understand individual components 8 http://www.atmel.com/Images/Atmel-42097- WIRELESS-AT02876-REB212BSMA-Hardware-User- Manual_Application-Note.pdf
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10 http://www.mathworks.com/matlabcentral/fx_files/30581/1/FSK.jpg Uses: Caller ID 3G Dial up Modem
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11 http://www.mathworks.com/matlabcentral/fx_files/30580/1/ASK.jpg Uses: Optical Fiber Laser Communication Short distance RF
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12 f(t) = cos(ωt + φ) http://www.hill2dot0.com/wiki/image s/thumb/3/30/MLG0013-binary- phase-shift-keying.jpg/300px- MLG0013-binary-phase-shift- keying.jpg http://www.mathworks.com/matlabcentral/fx_files/30582/1/PSK.jpg Uses: Cable Modem RFID Digital Video Broadcasting
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13 http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/RadCom/part19/fig6.gif
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14 16 States 4 Bits/Period (4^2 = 16) Utilizes both Amplitude and phase http://en.wikipedia.org/wiki/File:16QAM_Gray_Coded.svg http://www.answers.com/topic/qam-television
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15 Transmission: PAM Signal = Carrier Waveform x Digital pulses Reception: Digital Data (in pulses) = PAM Signal / Carrier Waveform http://vsagar.com/wp-content/uploads/2011/12/image63.png Uses: Ethernet
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Contains twisted pairs to limit amount of induced noise Various Ethernet types, speeds from 10 Mbit/s up to 100 Gbit/s http://randythetechprofessor.com/do-you-have-cable-confusion http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/0650/bks/SGI_Admin/books/IA_NetwkMail/sgi_html/ch01.html 17
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4 sets of twisted pair connections Transmit/Receive pairs Data sent in packets also called Ethernet Frames http://www.iprobot.net/uncategorized/network-cables/ http://www.doc.ic.ac.uk/~nd/surprise_97/journal/vol4/mhl/giga.html 18
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Most common Ethernet interfaces use PAM-5 (10BASE-T, 100BASE-TX) 5 voltage levels for modulation [-2, -1, 0, 1, 2] 10GBASE-T uses PAM-16 (DSQ128) for modulation http://ecee.colorado.edu/~ecen4242/ethernet/ethernet.html 19 http://www.rwmonline.org/Metrotek/SC/s2p9_frameset.htm
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Digital Modulation is the process of modulating a discrete signal in an analog one Carrier signals are useful where a bus may not be practical or possible Digital modulation is widely used in many forms of electromagnetic communication 20
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http://www.doc.ic.ac.uk/~nd/surprise_97/journal/vol4/mhl/giga.html http://en.wikipedia.org/wiki/Ethernet#Varieties_of_Ethernet http://ecee.colorado.edu/~ecen4242/ethernet/ethernet.html http://www.siemon.com/us/white_papers/images/05-02-17_wifi_why_for_us- freq-allocations-chart_big.jpg http://www.siemon.com/us/white_papers/images/05-02-17_wifi_why_for_us- freq-allocations-chart_big.jpg http://www.atmel.com/Images/Atmel-42097-WIRELESS-AT02876-REB212BSMA- Hardware-User-Manual_Application-Note.pdf http://www.atmel.com/Images/Atmel-42097-WIRELESS-AT02876-REB212BSMA- Hardware-User-Manual_Application-Note.pdf 21
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