BWU_BEC_21_008 NISHANT MANDAL how to decode any number with help of digital.pptx

how to decode to help of digilat system a=to analog system

1. PPT Topic – Decoder Submitted by –NISHANT MANDAL (BWU/BEC/21/008) Department – B.Tech Robotics and Automation Course Name – Digital System Design Course Code – PCC-ECR302 BRAINWARE UNIVERSITY

2. Definition Decoder is a combinational logic circuit that converts a binary code into the desired output signals. It is called decoder because it performs the reverse process of encoder. The process of converting binary input code into desirable output is known as decoding. A decoder consists of: Inputs(n) Output ( 2 n , numbered from 0 2 n – 1) Selectors / Enable (active high or active low) BRAINWARE UNIVERSITY

3. Cont… T he decoder has the characteristic that for each of the possible 2 n binary input number which can be taken by the n input cells the matrix will have a unique one of its 2 n output lines selected. Input n = 2 Output 2 2 = 4 Input n = 3 Output 2 3 = 8 BRAINWARE UNIVERSITY

4. Block diagram of Decoder n to m (n : m) decoder . . . . E n input lines m output lines Enable BRAINWARE UNIVERSITY

5. 2 to 4 line decoder T he simplest decoder is a 2 to 4 line decoder. I t has two inout S1 and S0 and four outputs denoted by D0, D1, D2 and D3. The output of the decoder is active HIGH. I n this decoder, note that S1 represents MSB and S0 is the LSB of the input code. 2 to 4 Decoder E S S 1 D D 1 D 2 D 3 BRAINWARE UNIVERSITY

6. Truth table of 2 to 4 decoder S 1 S D D 1 D 2 D 3 1 1 1 1 1 1 1 1 Input Output D = S 1 S D 1 = S 1 S D 2 = S 1 S D 3 = S 1 S BRAINWARE UNIVERSITY

7. Circuit diagram of 2 to 4 decoder D D 1 D 2 D 3 S 1 S BRAINWARE UNIVERSITY

8. In three to eight decoder, there are three inputs and eight outputs. S0 is the least significant variable, while S2 is the most significant variable. The three inputs are decoded into eight outputs namely D0, D1,…D7 . The function table indicates, binary values at the input from eight combinations activate the corresponding output line. 3 to 8 decoder BRAINWARE UNIVERSITY

9. Cont… D 3 to 8 Decoder E S 2 S S 1 D 1 D 2 D 3 D 4 D 6 D 7 D 5 BRAINWARE UNIVERSITY

10. Truth table of 3 to 8 decoder S 2 S 1 S D D 1 D 2 D 3 D 4 D 5 D 6 D 7 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Inputs Outputs BRAINWARE UNIVERSITY

11. Circuit diagram of 3 to 8 decoder D 1 S 2 S 1 S D D 4 D 6 D 7 D 3 D 2 D 5 BRAINWARE UNIVERSITY

12. Thank You