- This time-sharing is known as Time division Multiplexing (TDM).. - Second, the bandwidth of the microwave link can be divided among logical channels, with each user having exclusive possession of some frequency band. - This sharing by frequency band is known as Frequency division Multiplexing (FDM).. - Multiplexed circuits generally have to have the same capacity (bandwidth) as the sum of the circuits it combines.. - FDM Frequency Division Multiplexing 2. - TDM Time Division Multiplexing. - Frequency Division Multiplexing: (Chapter-3). - Time Division Multiplexing: (Chapter-3). - Time Division Multiplexing is used by the digital system where as FDM is used by the analogue system.. - The sampling rate should be at least double the frequency of the signal being sampled.. - North America’s T Carrier Digital Circuits form an interconnected synchronous digital communications system of leased circuits using Time Division Multiplexing.. - Voice Channels. - Time division multiplexing allows multiple T1 carriers to be multiplexed into higher-order carriers.. - Statistical Time Division Multiplexing (STDM): (Fig 4-24, p. - STDM is the exception to the rule that the capacity of the multiplexed circuit must equal the sum of the circuits it combines.. - They require internal buffering of the data being sent so data can be temporarily stored at times of heavy traffic.. - STDM provides more efficient use of the circuit because more terminals can share it simultaneously.. - Wavelength Division Multiplexing (WDM. - is the nothing but the Frequency division Multiplexing.. - refraction angle depends on the wavelength of the light. - This is used for fiber optic channels.. - Wavelength = Velocity of the wave / frequency. - In WDM the necessary condition is that the incoming channels has to use different frequencies, i.e., the light sources have to have different wavelength (in the range of 0.8 to 1.6 micrometers).. - Wavelength Division Multiplexing is preferred because it uses passive devices (prisms, not electronic circuits) to multiplex different optical signal and made it possible to utilize the bandwidth of a single optical fiber.. - This multiplexing will greatly increase the carrying capacity of the already high bandwidth optical fiber.
Xem thử không khả dụng, vui lòng xem tại trang nguồn hoặc xem
Tóm tắt