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8/11/2019 Multiplexing and Demultiplexer
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Raza hussnain Bsec 01103002
Majid amjad Bsec 01103018
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In electronics , a multiplexer(or mux) is a
device that selects one of
several analog or digital input signals and
forwards the selected input into a single
line.
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Num Ic num Fuction output
1 74157 Quad 2:1 mux Output same as input given
2 74158 Quad 2:1 mux Output is inverted input
3 74153 Dual 4:1 mux. Output same as input
4 74152 Dual 4:1 mux. Output is inverted input
5 74151a 16:1 mux. Both outputs available (i.e.,
complementary outputs)
6 74151 8:1 mux. Output is inverted input
7 74150 16:1 mux. Output is inverted input
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(FDM) Frequency division multiplexing
(WDM) Wavelength division multiplexing
(TDM)Time Division multiplexing
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FDM is applied when the bandwidth of a link (in hertz) is greater than
the combined bandwidths of the signals to be transmitted. In FDM,
signals generated by each sending device modulate different carrier
frequencies. These modulated signals are then combined into a single
composite signal that can be transported by the link. Carrier
frequencies are separated by sufficient bandwidth to accommodatethe modulated signal
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(WDM) is an analog multiplexing technique to combine optical signals.WDM isdesigned to use the high data rate capability of fiber-optic cable. The optical fiber
data rate is higher than the data rate of metallic transmission cable. Using a fiber-
optic cable for one single line wastes the available bandwidth. Multiplexing allows
us to combine several lines into one.
WDM is conceptually the same as FDM, except that the multiplexing and
demultiplexing involve optical signals transmitted through fiber-optic channels. Theidea is the same: We are combining different signals of different frequencies. The
difference is that the frequencies are very high.
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is a digital multiplexing technique for combining several low-rate
channels into one high-rate one.TDM is a digital process that allows several
connections to share the high bandwidth of a link Instead of sharing a portion of
the bandwidth as in FDM, time is shared. Each connection occupies a portion of
time in the link.Digital data from different sources are combined into one
timeshared link. However, this does not mean that the sources cannot produceanalog data; analog data can be sampled, changed to digital data, and then
multiplexed by using TDM.
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In networking, the technique of combiningseparate communication channels from
different sources into a single channel for
transmission over a wide area network(WAN) link
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Telephone
Video processing
Digital broadcasting
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A demultiplexer(or demux) is a device taking a single
input signal and selecting one of many data-output-lines,
which is connected to the single input. A multiplexer is
often used with a complementary demultiplexer on the
receiving end.
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no Ics Functions Output
1 74139 Dual 1:4 demux Output is inverted input
2 74156 Dual 1:4 demux Output is open collector
3 74138 1:8 demux. Output is inverted input
4 74138 1:8 demux.
5 74154 1:8 demux. Output is inverted input
6 74159 1:8 demux. Output is open collector and same
as input
http://en.wikipedia.org/wiki/Open_collectorhttp://en.wikipedia.org/wiki/Open_collector