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7/23/2019 Analog to Digital Converters Presentation

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Analog-to-digital converterAnalo

g-to-digital converter

Prepared by:Prepared by:

Selah al-BattahSelah al-Battah

Mohammed Al-khabbazMohammed Al-khabbaz

Atiyah AlnakhliAtiyah Alnakhli

Ali DumyatiAli Dumyati


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IntroductionIntroduction

--Signal in real !orld" light# oundSignal in real !orld" light# ound$$

--%hen you can a picture !ith a canner !hat the%hen you can a picture !ith a canner !hat thecanner i doing&& 'AD()canner i doing&& 'AD()

It i taking the analog in*ormation provided by theIt i taking the analog in*ormation provided by thepicture 'light) and converting into digitalpicture 'light) and converting into digital$$

--%hen you record your voice on your computer%hen you record your voice on your computer##


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Introduction cont,dIntroduction cont,d

--Since analog ignal can aume any value# noieSince analog ignal can aume any value# noiei interpreted a being part o* the original ignal$i interpreted a being part o* the original ignal$

Digital ytem# on the other hand# can onlyDigital ytem# on the other hand# can only

undertand t!o number# zero and one$ Anythingundertand t!o number# zero and one$ Anythingdi**erent *rom thi i dicardeddi**erent *rom thi i dicarded$$

--ere !e need a tranlator *rom analog to digital$ere !e need a tranlator *rom analog to digital$.he device !hich play thi /ob are called analog.he device !hich play thi /ob are called analog

to digital converterto digital converter$$


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Analog-to-digital converterAnalog-to-digital converter

--An analog-to-digital converter (abbreviated ADC,An analog-to-digital converter (abbreviated ADC,

A/D or A to D)A/D or A to D)i an electronic circuit that converti an electronic circuit that convert

continuou ignal to dicrete digital numbercontinuou i

gnal to dicrete digital number..

--.he digital output may be uing di**erent coding.he digital output may be uing di**erent codingcheme# uch a binary and t!o, complementcheme# uch a binary and t!o, complement

binary$ o!ever# ome non-electronic or onlybinary$ o!ever# ome non-electronic or only

partially electronic device# uch a ha*t encoder#partially electronic device# uch a ha*t encoder#can alo be conidered a AD(can alo be conidered a AD($$


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Techniques of ACDTechniques of ACD

--.here are variou techniue o* A3D.here are variou techniue o* A3D

converionconverion::

44$$including *lahincluding *lah$$22$$ucceive appro5imationucceive appro5imation$$

++$$Delta-encodedDelta-encoded$$

00$$IntegratorIntegrator$$

11$$delta igma or modulatordelta igma or modulator$$


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A direct conversion ADC or flash ADCA direct conversion ADC or flash ADC

-A direct converion i very *at# but uually ha-A direct converion i very *at# but uually haonly 7 bit o* reolution '216 comparator) oronly 7 bit o* reolution '216 comparator) or*e!er# a it need a large# e5penive circuit$ AD(*e!er# a it need a large# e5penive circuit$ AD(

o* thi type have a large die ize# a high inputo* thi type have a large die ize# a high inputcapacitance# and are prone to produce mitakecapacitance# and are prone to produce mitakeon the output 'by outputting an out-o*-euenceon the output 'by outputting an out-o*-euencecode)$code)$

--e5ample:e5am

ple:.hey are o*ten ued *or video or other *at ignal$.hey are o*ten ued *or video or other *at ignal$


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A ucceive appro5imation AD(A ucceive appro5imation AD(

.hi type ue a comparator to re/ect range o*.hi type ue a comparator to re/ect range o*

voltage# eventually ettling on a *inal voltage range$voltage# eventually ettling on a *inal voltage range$

.he !ay ucceive appro5imation !ork i through.he !ay ucceive appro5imation !ork i through

contantly comparing the input voltage to a kno!ncontantly comparing the input voltage to a kno!nre*erence voltage until the bet appro5imation ire*erence voltage until the bet appro5imation i

achieved$ At each tep in thi proce# a binaryachieved$ At each tep in thi proce# a binary

value o* the appro5imation i tored in a ucceivevalue o* the appro5imation i tored in a ucceive

appro5imation regiter 'SA9)$ the SA9 ue aappro5imation regiter 'SA9)$ the SA9 ue are*ernce voltage *or converionre*ernce voltage *or converion$$


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AA delta-encoded ADCdelta-encoded ADC

- A delta-encoded AD( ha an up-do!n- A delta-encoded AD( ha an up-do!n countercounterthat *eed athat *eed a'DA()$ .he input ignal and the DA( both go to a'DA()$ .he input ignal and the DA( both go to acomparator$ .he comparator control the counter$ .hecomparator$ .he comparator control the counter$ .hecircuit ue negativecircuit ue negative *eedback*eedback*rom the comparator to*rom the comparator to

ad/ut the counter until the DA(, output i cloe enoughad/ut the counter until the DA(, output i cloe enoughto the input ignal$ .he number i read *rom the counter$to the input ignal$ .he number i read *rom the counter$

- Delta converter have very !ide range# and highDelta converter have very !ide range# and highreolution # but the converion time i dependent on thereolution # but the converion time i dependent on the

input ignal level$input ignal level$

- Delta converter are o*ten very good choice to read real-Delta converter are o*ten very good choice to read real-!orld ignal$$!orld ignal$$
http://en.wikipedia.org/wiki/Counterhttp://en.wikipedia.org/wiki/Counterhttp://en.wikipedia.org/wiki/Feedbackhttp://en.wikipedia.org/wiki/Feedbackhttp://en.wikipedia.org/wiki/Feedbackhttp://en.wikipedia.org/wiki/Counter


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IntegratorIntegrator

An integratorAn integrator ADCADC'alo called'alo called ramp-compareramp-compare## dual-dual-slopeslopeoror multi-slopemulti-slopeAD() produce aAD() produce a a!-tooth ignala!-tooth ignal

that ramp up# then uickly *all to zero$ %hen the rampthat ramp up# then uickly *all to zero$ %hen the ramp

tart# a timer tart counting$ %hen the ramp voltagetart# a timer tart counting$ %hen the ramp voltage

matche the input# a comparator *ire# and the timer, valuematche the input# a comparator *ire# and the timer, value

i recorded$ .imed ramp converter reuire the leati recorded$ .imed ramp converter reuire the leatnumber o*number o* tranitortranitor$$

- .he ramp time i enitive to temperature&&- .he ramp time i enitive to temperature&&

.here are t!o olution: ue a clocked counter driving a.here are t!o olution: ue a clocked counter driving a

DA(DA(and then ue the comparator to preerve theand then ue the comparator to preerve the

counter, value# or calibrate the timed ramp$counter, value# or calibrate the timed ramp$
http://en.wikipedia.org/wiki/Sawtooth_wavehttp://en.wikipedia.org/wiki/Sawtooth_wavehttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Sawtooth_wave


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AA Sigma-Delta ADCSigma-Delta ADC

- Alo kno!n a a Delta-Sigma AD( over ample the- Alo kno!n a a Delta-Sigma AD( over ample the

deired ignal by a large *actor and *ilter the deireddeired ignal by a large *actor and *ilter the deired

ignal band$


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9eolution9eolution

--.he reolution o* the converter indicate the number o*.he reolution o* the converter indicate the number o*

dicrete value it can produce over the range o* voltagedicrete value it can produce over the range o* voltage

value$ It i uually e5preed in 'bit)$ =or e5ample# anvalue$ It i uually e5preed in 'bit)$ =or e5ample# an

AD( that encode an analog input to one o* 216 dicreteAD( that encode an analog input to one o* 216 dicrete

value ';$$$211) ha a reolution o* eight bit# ince 2>7 ?value ';$$$211) ha a reolution o* eight bit# ince 2>7 ?

216216$$

--9eolution can alo be de*ined electrically# and e5preed in9eolution can alo be de*ined electrically# and e5preed in

volt$ .he voltage reolution o* an AD( i eual to it overallvolt$ .he voltage reolution o* an AD( i eual to it overall

voltage meaurement range divided by the number o*voltage meaurement range divided by the number o*

dicrete valuedicrete value$$


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(ommercial analog-to-digital converter(ommercial analog-to-digital converter

--.hee are uually integrated circuit.hee are uually integrated circuit$$

--Mot converter ample !ith 6 to 20 bit o* reolution# andMot converter ample !ith 6 to 20 bit o* reolution# and

produce le than 4 mega ample per econd$ It i rare toproduce le than 4 mega ample per econd$ It i rare to

get more than 20 bit o* reolution$ Mega ampleget more than 20 bit o* reolution$ Mega ampleconverter are reuired in digital video camera# videoconverter are reuired in digital video camera# video

capture card# and .@ tuner card to convert *ull-peedcapture card# and .@ tuner card to convert *ull-peed

analog video to MP< digital video *ileanalog video to MP< digital video *ile$$

--(ommercial converter uually have ;$1 to 4$1 CSB error(ommercial converter uually have ;$1 to 4$1 CSB error

in their outputin their output$$


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Application to music recordingApplication to music recording

- AD( are integral to much current muicAD( are integral to much current muic

reproduction technology# ince much muicreproduction technology# ince much muic

production i done on computer" even !henproduction i done on computer" even !hen

analog recording i ued$analog recording i ued$- An AD( i till needed to create the P(M dataAn AD( i till needed to create the P(M data

tream that goe onto a compact dictream that goe onto a compact dic$$


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Other applicationsOther applications

- AD converter are ued virtually every!here !here anAD converter are ued virtually every!here !here an

analog ignal ha to be proceed# tored# or tranportedanalog ignal ha to be proceed# tored# or tranported

in digital *orm$ =at video AD( are ued# *or e5ample# inin digital *orm$ =at video AD( are ued# *or e5ample# in

.@ tuner card$ Slo! on-chip 7# 4;# 42# or 46 bit AD( are.@ tuner card$ Slo! on-chip 7# 4;# 42# or 46 bit AD( are

common in microcontroller$common in microcontroller$

- @ery *at AD( are needed in digital ocillocope# and are@ery *at AD( are needed in digital ocillocope# and are

crucial *or ne! application like o*t!are de*ined radiocrucial *or ne! application like o*t!are de*ined radio


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uetionuetion&&&&