A. Design a BCD to 7 segment decoder using

(a) Dual 4:1 multiplexers

(b) 1;16 demultiplexer

B. Design a 32:1 multiplexers using two 16:1 multiplexers.

C. Design a 1:32 demultiplexer using 1:8 and 1:16 demultiplexer.

D. Design a logic circuit for converting Excess-3 to 8421 code.

E. Design a GREY to BCD-code converter using MSI ICs and logic gates.

F. Design a pulse train 11011001 using MSI ICs.

G. Draw a diagram to show how IC 74237 can be used as an 8-output data distributor.

H. Design a four digit 7 segment display system.

I. Design a 5¥3 dot matrix display system to display alphanumeric character E.

J. Design a 64:1 multiplexer using 8:1 and 16:1 multiplexers.

The Correct Answer and Explanation is :

A. BCD to 7-Segment Decoder Designs

(a) Dual 4:1 Multiplexers

A Binary Coded Decimal (BCD) to 7-segment decoder can be designed using dual 4:1 multiplexers. The multiplexers have 4 data inputs, 2 control lines, and 1 output. Each 7-segment display requires a 7-bit output for each of the 7 segments.

The BCD value (4 bits) will be the input to the multiplexers.
Use two 4:1 multiplexers for controlling each segment (A-G) of the display.
The 4 inputs of the multiplexers will correspond to the different possible states of the BCD digit.
The 2-bit control input will select the correct combination of outputs for each segment.

(b) 1-to-16 Demultiplexer

A 1-to-16 demultiplexer takes a single input and selects one of the 16 outputs based on the 4 control lines. This is ideal for selecting the correct output from the 7-segment display.

The BCD input will be converted to control lines for the demultiplexer.
Each output corresponds to a combination of the segments (A-G) for each BCD digit.

(c) BCD to Decimal Decoder

The BCD to decimal decoder takes a 4-bit input (BCD) and provides a corresponding 10-bit output to drive a 7-segment display. For each input BCD value (0000 to 1001), the output will represent the corresponding decimal value on the display.

B. Design of a 32:1 Multiplexer using Two 16:1 Multiplexers

To design a 32:1 multiplexer using two 16:1 multiplexers:

Connect the inputs to two 16:1 multiplexers, where each multiplexer handles 16 inputs.
Use an additional 5th selection bit to choose which of the two 16:1 multiplexers should output to the final output.
The 5 selection bits will be split into 4 for the 16:1 multiplexers and 1 for selecting between the two multiplexers.

C. Design of a 1:32 Demultiplexer using 1:8 and 1:16 Demultiplexers

To design a 1:32 demultiplexer:

Use a 1:16 demultiplexer as the first stage.
The first demultiplexer will provide 16 outputs.
Use a 1:8 demultiplexer for the second stage to select from the 16 outputs, generating 32 total outputs.

D. Logic Circuit for Converting Excess-3 to 8421 Code

The excess-3 code adds 3 to the 8421 BCD value.
To convert Excess-3 to 8421:

Subtract 3 from the 4-bit Excess-3 code.
This can be done using a simple binary subtractor circuit.

E. GREY to BCD Code Converter Using MSI ICs

A Grey code to BCD converter will use flip-flops and logic gates.
Grey to Binary conversion requires XOR operations, and binary to BCD conversion involves 4-bit to 3-bit logic.

F. Design of a Pulse Train 11011001 Using MSI ICs

This design requires a pulse generator that outputs the sequence 11011001.
A simple way to generate this sequence is using a 4-bit counter combined with logic gates to decode the pattern.

G. Using IC 74237 as an 8-Output Data Distributor

IC 74237 is a 3-to-8 line decoder with active low outputs. It can be used as an 8-output data distributor by connecting data to the inputs and selecting which of the 8 lines to activate with the control inputs.

H. Design of a Four-Digit 7-Segment Display System

Use a 4-bit BCD to 7-segment decoder for each digit.
Use multiplexing to alternate between each digit, displaying one at a time on a common cathode 7-segment display.

I. Design of a 5×3 Dot Matrix Display System to Display the Character “E”

Create a 5×3 matrix to represent the letter “E.”
Use 3-to-8 decoders and row/column selection logic to control the LEDs in the matrix.

J. Design of a 64:1 Multiplexer Using 8:1 and 16:1 Multiplexers

The first stage consists of two 16:1 multiplexers to handle 32 inputs.
The second stage uses an 8:1 multiplexer to select from the outputs of the 16:1 multiplexers, resulting in a 64:1 multiplexer.

These designs use different combinations of multiplexers, demultiplexers, and decoders to efficiently implement various logic circuits and display systems. Each solution relies on breaking down larger designs into manageable components and utilizing available MSI ICs for practical implementations.