In optical communication system operating at 1200nm, only 2% of the source frequency is available for TV t ransmission having a bandwidth of 5 MHz. the number of TV channels that can be transmitted is

Options

A. 2 million
B. 10 million
C. 0.1 million
D. 1 million

Answer

D

Explanation

Optical source frequency, `v=(c)/(lambda)`
or `v=(3xx10^(8)xxms^(-1))/(1200xx10^(-9)m)=2.5xx10^(14)Hz`
Bandwidth of channel=2% of the source frequency
`=(2)/(100)xx2.5xx10^(14)Hz=5xx10^(12)Hz`.
Number of channels `=("Total bandwidth of channel")/("Bandwidth needed per channel")`
`=(5xx10^(12)Hz)/(5xx10^(6)Hz)=10^(6)`=1 million