Discussion de 2C

Lab work : Data Processing Circuit- 2(C) Topic : Demultiplexer Objectives : At the end of this experiments, student will be able to define ; i. ii.

The function of demultiplexer. The basic circuit and usage of demultiplexer

Equipment/ tools : i. ii. iii. iv.

Intergrated circuits ( 7404 and 7411) Logic trainer Jumper wires Datasheet of IC

Theory : Demultiplexer is cantrary from multiplexer. It’s function to receive data through one transmission line (seriel) and then distribute it to one of a few output product line. Demultiplexer have rather constituency line which functions to control data transmission. If demultiplexer have n contituency line so the product line is 2n. The demultiplexers block diagram as shown below.

Input

DEMUX

Output

n selector lines

Procedure : i. ii. iii. iv.

The circuit is connected by using IC 7404 and 7411 as shown below. The DC power supply and ground is connected to each IC. The data switches is set according to truth table. The data input is set to 1.

Discussion From this experiment we learn and understand about Demultiplexer. A demultiplexer is the

opposite of a multiplexer. In electronic devices, a demultiplexer is a logical circuit which takes a single input and sends out this input to one of several outputs available. During this process the output that has been selected is assigned the value 1, while the other outputs are assigned the value 0. The definition is slightly different when we are talking about demultiplexers in the context of networking. In the networking context, a demultiplexer is a device that receives multiple signals that have been transmitted on one line and then decodes these single line signals into separate multiple signals. A demultiplexer is usually always used in tandem with a multiplexer. Demultiplexers can be analog demultiplexers or digital demultiplexers. Digital demultiplexers generally function as decoders. For this demultiplexer experiment, the equipment used are intergrated circuit (7404,7411), logic trainer, jumper wires, datasheet of IC. Moreover, we used four and gate and 2 inverter. First, we choose two switches as selector line and one data input. The switches connect to each inverter and the data input is connected to input of an AND gate,(D0). Then the data input is connected to inputs of other three AND gate by looping from first AND gate(D0). The more two input of D0 is connected with the two inverters. Inputs of D1 is connected with an inverter and another one is connected with direct from switch. For D2 inputs, one is connected from direct switch and another one is connected with an inverter. The inputs of D3 is connected with direct from S1 and S2. Lastly, the two selector line,(S1,S2) is adjusted to (0,0) , (0,1) , (1,0) and (1,1) the results for output D0, D1,D2 and D3 are recorded in the table.

Conclusion From this experiment we can conclude that at the end of this experiment we able to define the function of demultiplexer. The main function of demultiplexer is a device that receives multiple signals that have been transmitted on one line and then decodes these single line signals into separate multiple signals. A demultiplexer is usually always used in tandem with a multiplexer. Demultiplexers can be analog demultiplexers or digital demultiplexers. Digital demultiplexers generally function as decoders. Moreover, we able to define and learn about the basic circuit and usage of demultiplexer. Demultiplexers are also categorized based on their usage. There may be three to four different types of demultiplexers. For example, in fiber optic connections, four different types of demultiplexers are used – multiple-length fibers, prisms, Bragg mirrors, and wave splitters. Demultiplexers can also be categorized based on their structure.

Question 3. What is the different beetwen multiplexer and demultiplexer?  A multiplexer selects one line from many lines. The inverse of selection is distribution. A demux essentially transmits data from one line line to 2^n possible output lines. The output line is determined by n select lines. In short, a multiplexer selects an input line, a demultiplexer selects an output line. The differences between these two circuits is subtle, as far as I can tell. A demux simply selects an output line, nothing more. It's a glorified switch. A decoder takes n inputs, and uses those inputs to determine which of the 2^n output lines is high. A decoder is designed to simply keep one line high. A demux is designed to set one output equal to the input (whether it be high, low, or a changing signal).

Selector lines

Choosen output

S1

S0

D0

D1

D2

D3

0

0

1

0

0

0

0

1

0

1

0

0

1

0

0

0

1

0

1

1

0

0

0

1