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Lesson Objectives

This lecture will help you to:Discuss about how to interface with analog world.

Understand D/A and A/D conversion:

Having basic knowledge on DAC and ADC.

Knowing several types of DAC and ADC.

Have some examples of ADC and DAC ICs.

Discuss on some typical applications.

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INTERFACE TO REAL WORLD

Binary value

A transducer is an electronic

device that converts energyfrom one form to another.

(focused on eletrical signal).

An actuator is a transducer that

accepts a signal and converts itto a physical action. (focused

on eletrical signal)

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DIGITAL TO ANALOG CONVERSION

Digital

to

Analog

CONVERTER

MSB

LSB

Vref= 16V

VoutDigitalinputs

D

C

B

A

D C B A Vout

0 0 0 0 0

0 0 0 1 1

0 0 1 0 2

0 0 1 1 3

0 1 0 0 4

0 1 0 1 5

0 1 1 0 6

0 1 1 1 7

1 0 0 0 8

1 0 0 1 9

1 0 1 0 10

1 0 1 1 11

1 1 0 0 12

1 1 0 1 13

1 1 1 0 14

1 1 1 1 15

Four-bit DAC with voltage output.

fullscale

stepsiz

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DIGITAL TO ANALOG CONVERSION

Weighted resistor DAC

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R/2R DAC

DIGITAL TO ANALOG CONVERSION

Unique resistor value

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Control: Analog control to adjust motors speed,

temperature, fluid/air flows, gas pressure, etc.

Automatic testing: produce pseudo-analog signal tofeed into analog circuitry (eg. Auto volume control).

Signal reconstruction: Reconstruct digitized storedsignals (eg. MP3 player)

A/D Conversion: Being an important part of ADC.

DAC APPLICATIONS

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DAC 0808 IC

Pinout and block diagram

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DAC 0808 IC

Typical application

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Analog to Digital Conversion

The process sequence

1

2

3

45

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Digital Ramp ADC

The process sequence

1

2

3

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Successive-Approximation ADC

4 bit SAC example

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FLASH ADC

The process sequence

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Digital Voltmeter

Digital Voltmeter using Digital-Ramp ADC

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ADC 0809 IC

Block diagram

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ADC 0809 IC

Pinout and typical application

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SUMMARY

What you have learned:

Interfacing with analog world process

Digital to Analog Conversion

DAC types

Analog to Digital Conversion

ADC types

Application examples

Intergrated Circuits

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QUESTIONS?