Multiplex and Demultiplex
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Multiplex and Demultiplex. © Cliff Strahan, May 1, 2001 Mux & Demux. To Multiplex a number of signal lines is to transmit them over a sin • A M! is a "ir"uit that "ombines t#o or more signals for transmi over a single line or path. • A $%M! is a "ir"uit that "onverts the multiplexe& signal ba"' i separate signals for &istribution. • (re)uen"y $ivision M! *($M+ uses mo&ulation te"hni)ues to trans the signals in &ifferent fre)uen"y ban&s. • Time $ivision M! *T$M+ uses s#it"hing te"hni)ues to transmit th signals in &ifferent time slots. A &igital M! C uses T$M to sen& bits from a number of inputs to one in se)uen"e. f properly syn"hronise&, no &ata is lost. The "ombine& have a bit rate n times the in&ivi&ual bit rate, #here n is the numb So a 1 of - M! #ith input &ata at 1'b s #ill have a "ombine& rate o ses of M! te"hnology in"lu&e/ • igh volume "ommuni"ations systems, su"h as long &istan"e telep "onne"tions. • arallel to serial an& serial to parallel "onversion. • $riving &isplays. • Communi"ations bet#een Cs. • arallel &ata s#it"hing. M! Cs are name& #ith referen"e to the number of input an& output pi • An 3 line to 1 line M! #ill be a single s#it"h that sele"ts fro eight input pins an& "onne"ts that input to the single output. 5sele"t6 pins, S 0 , S 1 7 S 2 . • An 3 line to - line M! #ill be four s#it"hes that sele"t a grou input pins an& "onne"t that group to the four output pins. t #i 5sele"t6 pin. • A - line to 2 line M! #ill be a &ouble s#it"h. %a"h s#it"h #ill from its - input pins an& "onne"ts that input to its output. The nee& 2 5sele"t6 pins, S 0 7 S 1 .
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Multiplex and Demultiplex
Transcript of Multiplex and Demultiplex
Multiplex and Demultiplex
Multiplex and Demultiplex.
Cliff Strahan, May 1, 2001
Mux & Demux.
To Multiplex a number of signal lines is to transmit them over a single line.
A MUX is a circuit that combines two or more signals for transmission over a single line or path.
A DEMUX is a circuit that converts the multiplexed signal back into separate signals for distribution.
Frequency Division MUX (FDM) uses modulation techniques to transmit the signals in different frequency bands.
Time Division MUX (TDM) uses switching techniques to transmit the signals in different time slots.
A digital MUX IC uses TDM to send bits from a number of inputs to one output in sequence. If properly synchronised, no data is lost. The combined signals will have a bit rate n times the individual bit rate, where n is the number of signals. So a 1 of 4 MUX with input data at 1kb/s will have a combined rate of 4kb/s.
Uses of MUX technology include:
High-volume communications systems, such as long distance telephone connections.
Parallel to serial and serial to parallel conversion.
Driving displays.
Communications between ICs.
Parallel data switching.
MUX ICs are named with reference to the number of input and output pins.
An 8-line to 1-line MUX will be a single switch that selects from the eight input pins and connects that input to the single output. It will need 3 select pins, S0, S1 & S2.
An 8-line to 4-line MUX will be four switches that select a group of four input pins and connect that group to the four output pins. It will need 1 select pin.
A 4-line to 2-line MUX will be a double switch. Each switch will select from its 4 input pins and connects that input to its output. The IC will need 2 select pins, S0 & S1.
