Pulse-Code-Modulation for master-PCM.ppt

electronics

1. 1
Pulse Code Modulation (PCM)

2. 2
Outline
-Analogue to Digital conversion.
-Sampling (PCM).
-Pulse Code Modulation Advantages.

3. 3
Pulse Code Modulation (PCM) is a
technique to convert analog data to
digital signal.

4. 4
Why’s to Analog to Digital Conversion
-Adigitalsignalissuperiortoananalogsignal.
-Digitalislesspronetonoiseanddistortion.
-Wecan’tuseanalogsignalsforlongdistance
(losetheirstrength,whichmeansamplifiersareneededto
amplifysignal.Howevertheamplifiercreatesdistortioninthe
signalandaddssomenoise).
-Thetendencytodayistochangeananalogsignal
(suchasaudio,voiceandmusic)todigitaldata.
.

5. 5
Analog to Digital Conversion
•Theideaofdigitizinganalogsignalstartedwith
telephonecompanies,toprovidelongdistance
services;Theydigitizedtheanalogsignalatthe
sender;Thesignalisconvertedbacktoanalogat
thereceiver.
-PulseCodeModulation(PCM):
1-Sampling(PAM).
2-Quantization.
3-Binaryencoding

6. 1. Sampling(PAM)
•ThefirststepinPCMissampling.
•Theanalogsignalissampledat
equalinterval,everyT
ss(sample
interval)

7. 1. SamplingPAM (Pulse Amplitude Modulation)

8. 8
2. Quantized PAM Signal
•TheresultofPAMisaseriesofpulseswithamplitudevalues
betweenthemaximumandminimumamplitudesofthe
signalwithrealvalues.
•Quantization:isamethodofassigningintegervaluesina
specificrangetosampledinstances.

9. 9
3. Binary Encoding
-Eachquantizedsamplesistranslatedintoequivalentbinary
codes.

10. 10
4. Output Encoding
-Thebinarydigitsarethentransformedtoadigitalsignalusing
oneofthelineencoding.

11. Components of PCM Encoder

12. Pulse Code Modulation Advantages
1.Analogsignalcanbetransmittedoverahighspeed
digitalcommunicationsystem.
2.Probabilityofoccurringerrorwillreducebytheuseof
appropriatecodingmethods.
3.PCMisusedinTelkomsystem,digitalaudiorecording,
digitizedvideospecialeffects,digitalvideo,voicemail.
4.PCMisalsousedinRadiocontrolunitsastransmitterand
alsoreceiverforremotecontrolledcars,boats,planes.
5.ThePCMsignalismoreresistanttointerferencethan
normalsignal.

13. Any Questions ?