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.

1
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 26106 log24 121062 24 Mbps
4. If a binary signal is sent over a 3-kHz
channel whose signal-to-noise ratio is 20 dB,
what is the maximum achievable data rate?
B 3 kHz 3.103 Hz S/NdB 20 dB S/NdB 10
log10S/N 20 10 log10S/N ? 2 log10S/N S/N
102 100
Dengan teorema Shannon C B log2(1S/N) C
3103log(1100) C 31036.656 19.975103
bps C 19.975 kbps
2
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 1.544106
bps (halaman 105) B 50 kHz 5104 Hz Dengan
teorema Shannon C B log2(1S/N) 1.544106
5104log2(1S/N) 30.88 log2(1S/N) 1S/N
230.88 1S/N 1976087932.808 ? S/N
1976087931.808 S/NdB 10 log10S/N S/NdB
10log101976087931.808 S/NdB 109.2958 92.958
dB
3
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 Best 2 hop Worst 2 hop Average 2 hop
RING (2 arah) Best 1 hop Worst n/2
hop Average n/4 hop
MESH (full connected) Best 1 hop Worst 1
hop Average 1 hop
Average untuk RING Ngenap ? Avg
Nganjil ? Avg