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Digital Modulation and Data T ransfer

Digital Modulation and Data T ransfer. Sam Parrotte Joshua Young Jason Hernandez November 19 th 2013. What is Digital Modulation? Why use it? How is it related to Embedded Systems? Sample Forms of Digital Modulation Ethernet. Overview.

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Digital Modulation and Data T ransfer

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  1. Digital Modulation and Data Transfer Sam Parrotte Joshua Young Jason Hernandez November 19th 2013

  2. What is Digital Modulation? • Why use it? • How is it related to Embedded Systems? • Sample Forms of Digital Modulation • Ethernet Overview

  3. 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 What is Digital Modulation • http://www.mathworks.com/matlabcentral/fx_files/30580/1/ASK.jpg

  4. Analog and Digital Representations http://upload.wikimedia.org/wikipedia/commons/a/a4/Amfm3-en-de.gif http://electronicdesign.com/communications/understanding-modern-digital-modulation-techniques

  5. Why Modulate Digital Information? • Demodulation techniques offer beneficial recovery abilities • Multiple parties share mediums to communicate information • Commonly shared mediums: • Cable • Air http://www.ghielectronics.com/img/www/products/381-0_small.jpg

  6. Xbee Spectrum 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

  7. http://www.siemon.com/us/white_papers/images/05-02-17_wifi_why_for_us-freq-allocations-chart_big.jpghttp://www.siemon.com/us/white_papers/images/05-02-17_wifi_why_for_us-freq-allocations-chart_big.jpg

  8. Router Access • Send information to a server • Interact with Wifi devices • Direct communicationbetween devices • When sending high data rates • When multiple devices sharea medium • Commercial RF Product • Can’t use predesigned boards • Must understand individual components Why is this important for Embedded Systems? http://www.atmel.com/Images/Atmel-42097-WIRELESS-AT02876-REB212BSMA-Hardware-User-Manual_Application-Note.pdf

  9. Types of Modulation

  10. FSK - Frequency Shift Keying • Uses: • Caller ID • 3G • Dial up Modem http://www.mathworks.com/matlabcentral/fx_files/30581/1/FSK.jpg

  11. ASK - Amplitude Shift Keying • Uses: • Optical Fiber • Laser Communication • Short distance RF http://www.mathworks.com/matlabcentral/fx_files/30580/1/ASK.jpg

  12. PSK - Phase Shift Keying http://www.hill2dot0.com/wiki/images/thumb/3/30/MLG0013-binary-phase-shift-keying.jpg/300px-MLG0013-binary-phase-shift-keying.jpg f(t) = cos(ωt + φ) • Uses: • Cable Modem • RFID • Digital Video Broadcasting http://www.mathworks.com/matlabcentral/fx_files/30582/1/PSK.jpg

  13. QPSK - Quadrature Phase Shift Keying http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/RadCom/part19/fig6.gif

  14. QAM - Quadrature Amplitude Modulation http://www.answers.com/topic/qam-television • 16 States • 4 Bits/Period (4^2 = 16) • Utilizes both Amplitude and phase http://en.wikipedia.org/wiki/File:16QAM_Gray_Coded.svg

  15. PAM - Pulse Amplitude Modulation Transmission: PAM Signal = Carrier Waveform x Digital pulses Reception: Digital Data (in pulses) = PAM Signal / Carrier Waveform • Uses: • Ethernet http://vsagar.com/wp-content/uploads/2011/12/image63.png

  16. Ethernet in Digital Modulation

  17. Contains twisted pairs to limit amount of induced noise • Various Ethernet types, speeds from 10 Mbit/s up to 100 Gbit/s Ethernet 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

  18. 4 sets of twisted pair connections • Transmit/Receive pairs • Data sent in “packets” also called “Ethernet Frames” Overview of Ethernet http://www.iprobot.net/uncategorized/network-cables/ http://www.doc.ic.ac.uk/~nd/surprise_97/journal/vol4/mhl/giga.html

  19. 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 PAM in Ethernet http://ecee.colorado.edu/~ecen4242/ethernet/ethernet.html http://www.rwmonline.org/Metrotek/SC/s2p9_frameset.htm

  20. 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 In Conclusion…

  21. http://www.doc.ic.ac.uk/~nd/surprise_97/journal/vol4/mhl/giga.htmlhttp://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.atmel.com/Images/Atmel-42097-WIRELESS-AT02876-REB212BSMA-Hardware-User-Manual_Application-Note.pdf References

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