Encoders and decoders
- 2. ENCODERS •An encoder is a device, circuit, transducer, software program, algorithm or person that converts information from one format or code to another. The purpose of encoder is standardization, speed, secrecy, security, or saving space by shrinking size. They accept one or more inputs and generate a multibit output code.
- 3. An encoder is a combinational logic circuit that generate n output lines from 2n (or less) inputs. It has the reverse function of the decoder.
- 4. ADVANTAGES •To store more data in a given space •To send more data from source to destination. •To detect the errors easily.
- 5. ENCODER WITH ENABLE INPUT } } E= 1 Start Encoding (Enable the circuit) E= 0 No Operation (Disable the circuit E= 0 Start Encoding (Enable the circuit) E= 1 No Operation (Disable the circuit
- 6. DECIMAL TO BCD ENCODER
- 7. LOGIC EQUATION LOGIC DIAGRAM
- 8. TYPES OF ENCODER SIMPLE ENCODER 1.) 4 BY 2 ENCODER
- 9. TRUTH TABLE
- 10. LOGICAL EXPRESSION • A = Y2 + Y3 • B = Y1 + Y3 LOGIC DIAGRAM
- 11. 2.) 8 BY 3 ENCODER OCTAL TO BINARY ENCODER TRUTH TABLE LOGICAL EXPRESSION A = D1 + D3 + D5 + D7 B= D2 + D3 + D6 + D7 C = D4 + D5 + D6 +D7
- 12. LOGIC DIAGRAM
- 13. PRIORITY ENCODER • Has more than 1 input which is activated based on priority, meaning it is used to control interrupt request by acting according to highest priority. valid bit indicator
- 14. TRUTH TABLE
- 15. LOGIC EQUATION • K-MAP • A= D2 + D3 • B= D3 + D1D2 • V= D0 + D1 + D2 + D3
- 16. LOGIC DIAGRAM
- 17. 8 BY 3 ENCODER
- 18. EXAMPLE:
- 19. EXAMPLE:
- 20. DECODER • The process of taking some type of code and determining what it represents in terms of a recognizable number or character is called decoding. A decoder is a combinational logic circuit that performs the decoding function, and produce an output that indicates the (meaning) of the input code. • The decoder is called n to m where m < 2n for example two to four line decoder,
- 21. • Fig. (1) shows a two to four line decoder and its truth table.
- 22. LOGIC DIAGRAM
- 23. THE BCD DECODER • The BCD decoder converts each BCD code (8421) into one of ten possible decimal digit indications. It is typically referred to as a 1 of 10 or 4 to 10 lines decoder, although other types of decoder also fall into this category (such as an Execs – 3 decoder). A list of the ten BCD code words and their corresponding decoding functions is shown in Table (2). Each of these decoding functions is implemented with NAND gates to provide active LOW outputs, as shown in Fig. (2)
- 24. • The 7442 is an integrated circuit BCD to Decimal decoder. Note that on this device the inputs are A, B, C, and D where A is the least significant bit.
- 25. THANK YOU!