Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
3. Television channels are 6 MHz wide. How many bits/sec can be sent if four-level digital signals are used? Assume a noiseless channel. Menggunakan teorema Nyquist : B = 6 MHz = 6.106 Hz M = 4 level tegangan sinyal digital C = 2B log2M C = 2*6*106 log24 = 12*106*2 = 24 Mbps 4. If a binary signal is sent over a 3-kHz channel whose signalto-noise ratio is 20 dB, what is the maximum achievable data rate? B = 3 kHz = 3.103 Hz Dengan teorema Shannon : dB S/N = 20 dB C = B log2(1+S/N) C = 3*103*log(1+100) S/NdB = 10 log10S/N C = 3*103*6.656 = 19.975*103 bps 20 = 10 log10S/N 2 = log10S/N C = 19.975 kbps S/N = 102 = 100 5. What signal-to-noise ratio is needed to put a T1 carrier on a 50-kHz line? T1 carrier mempunyai C = 1.544 Mbps = 1.544*106 bps (halaman 105) B = 50 kHz = 5*104 Hz Dengan teorema Shannon : C = B log2(1+S/N) 1.544*106 = 5*104*log2(1+S/N) 30.88 = log2(1+S/N) 1+S/N = 230.88 1+S/N = 1976087932.808 S/N = 1976087931.808 S/NdB = 10 log10S/N S/NdB = 10*log101976087931.808 S/NdB = 10*9.2958 = 92.958 dB 41. Three packet-switching networks each contain n nodes. The first network has a star topology with a central switch, the second is a (bidirectional) ring, and the third is fully interconnected, with a wire from every node to every other node. What are the best-, average-, and-worst case transmission paths in hops? STAR RING (2 arah) MESH (full connected) Best : 2 hop Best : 1 hop Best : 1 hop Worst : 2 hop Worst : n/2 hop Worst : 1 hop Average : 2 hop Average : n/4 hop Average 1 hop Average untuk RING ( n / 2 ) 1 n/2 ( n 1) / 2 x N=genap Avg = x N=ganjil Avg = 2 * x x 1 x 1 n 1 x 1