Zhou, HuanXian (ID: 0225418)
HW2
EE136
Instructor: Kang Xi
3.13 a. Suppose that a digitized TV picture is to be transmitted from a source that uses a
matrix of 480X500 picture elements (pixels), where each pixel can take on one of 32 intensity
values. Assume that 30 pictures are sent per second. (This digital source is roughly equivalent
to broadcast TV standards that have been adopted.) Find the source rate.
Bits/pixel, n, 2^n=32, n=5 bits/pixel.
Source rate = bit/second × bits/pixel = 30 × 480 × 500 × 5
= 36000000 bits/sec = 36 Mbps
b. Assume that the TV picture is to be transmitted over a channel with 4.5 MHz bandwidth
and a 35 dB signaltonoise ratio. Find the capacity of the channel (bps).
10×log
10
SNR = 35 dB
log SNR = 35/10
SNR = 10^(3.5) = 3162.28
Channel capacity: C = B × log
2
(1+SNR) = (4.5×10^6)× log
2
(1+3162.28)
= 52.3Mbps
3.15 What is the channel capacity for a teleprinter channel with 300Hz bandwidth and SNR of
3dB, where the noise is white thermal noise?
10×log
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 Spring '11
 dong
 Channel capacity, Signaltonoise ratio, Pixel, NTSC

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