Question

5. Find the Fourier Transform, X(f), for a logical 1 bit for each of the following line codes A. RZ B. NRZ-L C. Biphase-L D. AMI

Answer 1

We can transmit bits over a wire , RF , Fiber through:

1.Line codes,

2. Power spectrum of line codes(Fourier transform)

3. Clock signal and synchronization

4. Common serial communications systems

Line Coding:

◮ Goal is to transmit binary data (e.g., PCM encoded voice, MPEG encoded video, financial information)

◮ Transmission distance is large enough that communication link bandwidth is comparable to signal bandwidth.

◮ Connections between nearby logic gates have bandwidth greater than switching speed, so no line coding is needed. But longer connections use pulse shaping

. ◮ Multiple links may be used, with regenerative repeaters

◮ First consider baseband communication (e.g., single twisted pair)

PSO of Polar signalling KPD - + pli ol - Plt) Since and a (nto) are independent and equally likely; Rolim is an Nha QN Y - lim 1 § 1 =18 -N N Ntv N --N N Ro= aka D=0 lim I s NA & 2N k=-N Sy(E)= |PCE) L R = |P(4) 16 Ibi

Examples? → NR 2 (100% Pulse) PH ) = x(t/16) (f) = To sinc (agf) fPCPDPE Th* sinclator) → RZ Half-width PCt2 = X(+(Tb/22) P(E) = 1 I sine (4ab) 1953)- To 28 ( 142 804) FOR R2, ish-ba -42 the 22 42 67 8R T Th To The