1. Mr. Thilak de Silva. BSc. Eng., MSc, CEng, FIE(SL), FIET(UK), CITP(UK), MBCS(UK), MIEEE (USA) M.Sc. in IT - Year 1 Semester II - 2012

2.  Jitter  Digital to Digital Conversion  Line coding  Block coding  Scrambling  Analog to Digital Conversion M.Sc. in IT - Year 1 Semester II - 2012

3.  At the end of this session you will have a broad understanding of Digital to Digital conversion and Analog to Digital Conversion of signals. M.Sc. in IT - Year 1 Semester II - 2012

4.  All data packets may not follow the same route.  Due to delays (in routers, media etc) different data packets reach the destination at different times.  Then jitter occurs.  Is vital in multimedia applications. M.Sc. in IT - Year 1 Semester II - 2012

5.  Line coding – converting digital data into a digital signal that can be transmitted through a transmission media.  Data elements – what we need to send  Signal elements – what we can send  Signal elements are the carriers who carries data elements. M.Sc. in IT - Year 1 Semester II - 2012

6. Source - http://train-srv.manipalu.com/wpress/wp-content/uploads/2011/10/clip-image0044-thumb4.jpghttp://train-srv.manipalu.com/wpress/wp-content/uploads/2011/10/clip-image0044-thumb4.jpg Ratio (r)= Data elements Signal elements

7.  Unipolar - NRZ  Polar – NRZ,RZ and biphase(Manchester and differential Manchester)  Bipolar-AMI and pesudoternary  Multilevel – 2B/1Q, 8B/6T and 4D-PAM5  Multitransition – MLT 3 M.Sc. in IT - Year 1 Semester II - 2012

8.  8 binary values in 6 signals  Additional Combinations = 729 – 256 = 473 M.Sc. in IT - Year 1 Semester II - 2012 10110011 -0++0- DataSignal 2^8 =2563^6 =729

9.  256 number of combinations are already defined and if there are any undefined combinations, that means there is a error.  Having additional combinations leads to easy error detection at the receiving end M.Sc. in IT - Year 1 Semester II - 2012

10.  Every line coding schema should have,  Error Detection and  Self Synchronization (done by PLL)  PLL will not Operate if there are no state changes  Eg: All 0 s in RZ M.Sc. in IT - Year 1 Semester II - 2012

11. Source :http://www.google.lk/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Transmission_line_element.svg/220px- Transmission_line_element.svg.png&imgrefurl=http://en.wikipedia.org/wiki/Characteristic_impedance&usg=__mIMtU47Cbk5Fjqt5yYJ1BPgoJYI=&h=134&w=220&sz=4&hl=en&start=1&zoom=1&tbnid=_ 6PLMVwREZh4GM:&tbnh=65&tbnw=107&ei=n6kmT_6EE87NrQf8lvyoCA&prev=/search%3Fq%3Dcharacteristic%2Bimpedance%26hl%3Den%26gbv%3D2%26tbm%3Disch&itbs=1http://www.google.lk/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Transmission_line_element.svg/220px- Transmission_line_element.svg.png&imgrefurl=http://en.wikipedia.org/wiki/Characteristic_impedance&usg=__mIMtU47Cbk5Fjqt5yYJ1BPgoJYI=&h=134&w=220&sz=4&hl=en&start=1&zoom=1&tbnid=_ 6PLMVwREZh4GM:&tbnh=65&tbnw=107&ei=n6kmT_6EE87NrQf8lvyoCA&prev=/search%3Fq%3Dcharacteristic%2Bimpedance%26hl%3Den%26gbv%3D2%26tbm%3Disch&itbs=1 R - resistance per unit length, L - inductance per unit length, G - conductance of the dielectric per unit length, C - capacitance per unit length, j - imaginary unit, and ω - angular frequency.

12.  Because of capacitor signal gets charged,  In Manchester coding it gets charged to a some extent and remains.  We need to have a way of discharging DC component, (avg =0), Eg: AMI M.Sc. in IT - Year 1 Semester II - 2012

13.  Changes a block of m bits into a block of n bits. (n>m)  Eg:  4B/5B coding – 4 bits converted to 5 bits (32-16 = 16 number of redundant combinations)  8B/10B – 8 bits are converted to 10 bits M.Sc. in IT - Year 1 Semester II - 2012

14. Block Coding Line coding Block Coding DATA Convert data to signal For Error detection Sender Receiver Transmissi on media

15.  Long sequence of zeros (0) are converted into a combination of bits. 000000010110  Mainly for synchronization.  Useful to achieve security.  Eg:  B8ZS  HDB3 M.Sc. in IT - Year 1 Semester II - 2012

16.  Converting an Analog signal to a Digital signal.  Used in telephone systems to convert the voice signal to digital signal.  Eg:  Pulse Code Modulation  Delta Modulation  Adaptive Delta Modulation M.Sc. in IT - Year 1 Semester II - 2012

17.  Data Communications and Networking, Forouzan, Chapter 04, 4 th Edition M.Sc. in IT - Year 1 Semester II - 2012