Line coding - NTNU

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Partial response c k = ±1 F(z) y k F(z) = (1 - z -1 ) m · (1 + z -1 ) n Digital Communication, Line codes and scrambling IET, NTNU 23 Alternatives of partial response Type partial response n = m = F(z)= Dicode 0 1 1-z -1 Duobinary 1 0 1+z -1 Modified duobinary 1 1 (1+z -1 )(1-z -1 )=1-z -2 1 z 1 =1 exp( j2fT) = 2 j exp( jfT) sin(fT), ) : zero at f = 0 1+ z 1 =1+ exp( j2fT) = 2 exp( jfT) cos(fT), ) : zero at f =1/(2T) Digital Communication, Line codes and scrambling IET, NTNU 24
Duobinary partial response y k = c k + c k-1 c k c k-1 Output y k -1 -1 -2 -1 1 0 1 -1 0 1 1 2 For duobinary, a two-level signal is coded into three levels. Modified duobinary and dicode will also have three-level output for binary input. Other alternatives of partial response will have more output levels. Digital Communication, Line codes and scrambling IET, NTNU 25 Spectral shaping by partial response Digital Communication, Line codes and scrambling IET, NTNU 26
Page 1 and 2: Presentation in course TTT4130 Digi
Page 3 and 4: Example, 4B3T code The 4B3T code is
Page 5 and 6: DC-balance Most transmission system
Page 7 and 8: Eye curve for AMI code with DC cuto
Page 9 and 10: Power spectrum AMI code Digital Com
Page 11: One alternative of a 4B3T code Digi
Page 15 and 16: Scrambling • Most transmission sy
Page 17 and 18: Applications of scrambling • Echo

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