Encoder and decoder

20
Encoder and Decoder Encoding, Decoding

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This presentation contains the Encoder and Decoder details

Transcript of Encoder and decoder

Page 1: Encoder and decoder

Encoder and Decoder

Encoding, Decoding

Page 2: Encoder and decoder

Encoder

ENCODER- a digital circuit that

produces a binary output code

depending on which of its inputs are

activated.

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DECODER- a digital circuit that converts

an input binary code into a single

numeric output.

Decoder

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ENCODERS AND DECODERS

A 0

A 1

A 2

A 3

A 4

A 5

A 6

A 7

ENCODER

O 0

O 1

O 2

A 0

A 1

A 2

O 0

O 1

O 2

O 3

O 4

O 5

O 6

O 7

DECODER

ONLY ONE INPUT ACTIVATED AT A TIME

BINARY CODE OUTPUT

BINARY CODE INPUT

ONLY ONE OUTPUT ACTIVATED AT A TIME

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THE 8421 BCD CODE

• BCD stands for Binary-Coded Decimal.

• A BCD number is a four-bit binary group that represents one of the ten decimal digits 0 through 9.

Example:

Decimal number 4926 4 9 2 6

8421 BCD coded number 0100 1001 0010 0110

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ELECTRONIC ENCODER -

DECIMAL TO BCD

0

Decimalto

BCDEncoder

BCD output

Decimal input0 0 0 0

5

0 1 0 1

7

0 1 1 1

3

0 0 1 1

• Encoders are available in IC form.• This encoder translates from decimal

input to BCD output.

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10 line to 4 line Encoder

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ENCODER1248

DECIMAL BINARY (BCD)

9 5V

8 5V

7 5V

6 5V5 5V

4 5V3 5V

2 5V1 5V

74147I9I8I7I6I5I4I3I2I1

A0A1A2A3

10 line to 4 line Encoder

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0

1

2

3

4

5

6

7

8

9

DECODER

BINARY (BCD)

DECIMAL

1 0V

2 0V

4 0V

8 0V

74LS42

A3A2A1A0

9876543210

4 line to 10 line Decoder

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BCD-to-7-SegmentDecoder/

Driver

DECODERS: BCD TO 7-SEGMENT DECODER/DRIVER

BCD input

0 0 0 00 0 0 0

Decimal outputLED

0 0 0 10 0 0 10 0 1 00 0 1 00 0 1 10 0 1 10 1 0 00 1 0 0

• Electronic decoders are available in IC form.• This decoder translates from BCD to decimal.• Decimals are shown on an 7-segment LED display.• This IC also drives the 7-segment LED display.

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BCD-to-7-SegmentDecoder/

Driver

BCD inputDecimal output

0 0 1 1

?

Q #1- What is the decimal output from the decoder that appears on the 7-segment display?

Answer: 3

Q #2- What is the decimal output from the decoder that appears on the 7-segment display?

0 0 0 0

Answer: 0

Q #3- What is the decimal output from the decoder that appears on the 7-segment display?

1 0 0 1

Answer: 9

Q #4- What is the decimal output from the decoder that appears on the 7-segment display?

Answer: 7

0 1 1 1

Q #5- What is the decimal output from the decoder that appears on the 7-segment display?

Answer: 6

0 1 1 0

TEST

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BCD-TO-SEVEN SEGMENT DECODER DRIVER

5V

abcdef g .

V+

74LS47A3A2A1A0

testRBI

gfedcba

RBO

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TEST

A 0

A 1

A 2

A 3

A 4

A 5

A 6

A 7

ENCODER

O 0

O 1

O 2

O 3

A 8

A 9

INPUT O3 O2 O1 O0A1=1A4=1A6=1A8=1

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TEST

A 0

A 1

A 2

O 0

O 1

O 2

O 3

O 4

O 5

O 6

O 7

DECODER

O 8

O 9

A 3

A3 A2 A1 A0 OUTPUT0 0 0 00 1 0 10 1 1 11 0 0 1

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TEST

ANSWER THE FOLLOWING QUESTIONS WITH ONE OR MORE OF

THESE WORDS: MUX, DEMUX, ENCODER, DECODER.

A. Has more inputs than outputs. ENCODER, MUX

B. Uses select inputs. MUX, DEMUX

C. Can be used in parallel-to-serial conversion. MUX

D. Produces a binary code at its output. ENCODER

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E. Only one of its outputs is activated at one time. DEMUX, DECODER

F. Used to route input signals to one of several outputs. MUX

G. Used to generate arbitrary logic functions. MUX, DEMUX

H. 3 line-to-8 line or binary to octal. DECODER

I. Data Selectors are also MUX.

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The End

….. Thank you ….