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Only 2% of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm. If an audio signal requires a bandwidth of 8 kHz, how many channels can be accommodated for transmission : (A) 375 x 107 (B) 75 x 107 (C) 375 x 108 (D) 75 x 109 |
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Answer» Correct option is (B) 75 x 107 Frequency at 1000 nm = 3 x 10/ 1000 x 10-9 ⇒ 3 x 1014 Hz available for channel band width = 2/100 x 3 x 1014 ⇒ 6 x 1012 Hz Bandwidth for 1 channel = 8000 Hz ∴ No. of channel 6x1012/ 8x103 ⇒ 600/8 x 107 = 75 x 107 |
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