roblen A) Why does modal distortion limit the maximum possible bit rate through
ID: 2305095 • Letter: R
Question
roblen A) Why does modal distortion limit the maximum possible bit rate through an optical fiber? B) If the speed of light in an optical fiber depends on the frequency of the light, a pulse wl spread as it propagates through an optical fiber. Why is this so? Problem 83. Do some internet research and then answer the following questions A) What are the carrier frequencies and bandwidths associated with the 802.11ac wireless internet (WiFi) standard B) What is the frequency range used by "over the air VHF channels 2-13 in the United States?Explanation / Answer
82] A]
A high bit rate means that the number of bits that will be transmitted per second through the fiber will large.
For a multimode fiber, the propagating modes travel at different speeds (because of the positive dispersion of the material of the fiber) and thus the signal gets spread in time. So, if the signal is transmitted in 10ns pulses, the pulse width will become greater due to dispersion and fewer pulses would have to be sent in a given second to avoid increasing the bit error rate. This limits the maximum possible bit rate through the fiber.
B] If the speed of light in an optical fiber depends on the frequencies, the speed of propagation for higher and lower frequencies will be different. So, after propagating through a given distance, the signals from the two frequencies will be out of phase thereby spreading a pulse signal containing these frequencies in time.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.