Digital communication- student version
description
Transcript of Digital communication- student version
![Page 1: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/1.jpg)
ד"ר אורי מחלב
Digital communication- Digital communication- student versionstudent version
Dr. Uri Mahlab
![Page 2: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/2.jpg)
ד"ר אורי מחלב
General overviewGeneral overview
Digital Radio Theoryand Implementation
-How a Digital Radio Works
![Page 3: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/3.jpg)
ד"ר אורי מחלב
Digital Radio Block DiagramDigital Radio Block Diagram
CO
DER MOD
UPCONVERTER
DOWNCONVERTER
DEMOD
DE C
OD
E R
![Page 4: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/4.jpg)
ד"ר אורי מחלב
Analog vs. Digital ModulationAnalog vs. Digital Modulation
AM
FM
PM
DIGITAL
With digital modulation information is in the phase and
amplitude of the signal
![Page 5: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/5.jpg)
ד"ר אורי מחלב
The IQ DiagramThe IQ Diagram
Vq
Vi
magnitude
phase
Q
I
![Page 6: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/6.jpg)
ד"ר אורי מחלב
Analog Modulation on the IQ diagramAnalog Modulation on the IQ diagram
Q
I
B
A
C
D
FM
PM
![Page 7: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/7.jpg)
ד"ר אורי מחלב
BPSK Timing and State DiagramBPSK Timing and State Diagram
Reference
State 1 State 0
= 0 deg. = 180 deg.
0 State 1 State
BPSK
Constellation
Diagram
Q
I
t
![Page 8: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/8.jpg)
ד"ר אורי מחלב
QPSK ModulationQPSK Modulation
Q
I
00
1011
01
Vi
Vq
4 Possible States
![Page 9: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/9.jpg)
ד"ר אורי מחלב
16 QAM State Diagram16 QAM State Diagram
Q
I
0000 00110001
01010100 0111
1100
0010
1101
0110
10011000 1010
1110
1011
1111
![Page 10: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/10.jpg)
ד"ר אורי מחלב
Symbol Rate:Symbol Rate:
“The rate at which the carrier
moves between points in the
constellation”
![Page 11: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/11.jpg)
ד"ר אורי מחלב
Example:Example:
16 Mb/s4 Bits
A 16 QAM radio has 4 bit per state (or symbol).
If the radio operates at 16 Mb/s, then the
carrier must change states
or
4 million times per second (4 MBaud)
SYMBOL RATE = 4MHz
![Page 12: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/12.jpg)
ד"ר אורי מחלב
Some Typical Modulation FormatsSome Typical Modulation Formats
BPSK QPSK 8PSK
16QAM 64QAM
![Page 13: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/13.jpg)
ד"ר אורי מחלב
QPSK ModulatorQPSK Modulator
SERIAL TOPARALLEL
CONVERTERCARRIER PHASE
SHIFT BPFCOMBINER
00
11 10
01
COMBINED VECTOR
STATE DIAGRAM
BALANCED
MODULATION
BALANCED
MODULATION
QUADRATURE DATA STREAM
IN-PHASE DATA STREAM
fs = fb/2
BINARY
NRZ
INPUT
SIGNAL
fb
SYMBOL RATE:fs = fb/2
I
Q
I.F0°
90°
![Page 14: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/14.jpg)
ד"ר אורי מחלב
I, Q, Eye diagram and ConstellationI, Q, Eye diagram and Constellation
EYE
I
Q
+1
-1
+1
-1
CONSTELLATION :
I
Q
1,4
5 3
2
![Page 15: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/15.jpg)
ד"ר אורי מחלב
QPSK DemodulatorQPSK Demodulator
BPF PowerSplitter
CarRec.
PhaseSplitter
Symboltiming
rec.(STR)
Parallelto serial
converter
LPF.
LPF.
ThreshComp.
ThreshComp.
IF
Input
Phase
Demodulation
Phase
Demodulation
Binary
NRZfb
fb/2
fb/2
I
Q
I
Q
0°
90°
![Page 16: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/16.jpg)
ד"ר אורי מחלב
16 QAM Modulator16 QAM Modulator
Data
2-to-4level
convert
2-to-4level
convert
Premod.LPF
Premod.LPF
Phasesplit BPFLO
L.F.
16 QAM
Output
0°
90°
Q
I
4bf
4bfI
Q
2bf
2bf
Binary
NRZ
Data
bf
![Page 17: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/17.jpg)
ד"ר אורי מחלב
16 QAM Demodulator16 QAM Demodulator
BPF CR STR
X2datacon
blner
LPF
LOGIC
1thV
2thV
3thV
4-to-2 level converterof Q channel. Samedesign as I channel.
IF Input
I
Q
0°
90°
4-LevelSignal
4-LevelSignal
4bf
4bf
Regeneration
DataOutfb
2bf
2bf
LPF
![Page 18: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/18.jpg)
ד"ר אורי מחלב
Which waveform requires more bandwidth?Which waveform requires more bandwidth?
A
B
time
![Page 19: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/19.jpg)
ד"ר אורי מחלב
Bandwidth ConsiderationsBandwidth Considerations
![Page 20: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/20.jpg)
ד"ר אורי מחלב
Two random data sequenceTwo random data sequence
timefrequency
![Page 21: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/21.jpg)
ד"ר אורי מחלב
Unfiltered Digital Radio SpectrumUnfiltered Digital Radio Spectrum
0f SFf 0 SFf 20 SFf 30 SFf 40 SFf 0SFf 20 SFf 30 SFf 30 SFf 50
![Page 22: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/22.jpg)
ד"ר אורי מחלב
An UNFILTERD RadioAn UNFILTERD Radio
CO
DER MOD U/C
D/C DEMOD
DEC
OD
ERtime
time
frequency
Data is easier to
recover but signal
requires a lot of
bandwidth
![Page 23: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/23.jpg)
ד"ר אורי מחלב
A FILTERED RadioA FILTERED Radio
CO
DER MOD U/C
D/C DEMOD
time
time
frequency
Signal requires less
bandwidth but data
is filtered
DEC
OD
E R
![Page 24: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/24.jpg)
ד"ר אורי מחלב
Intersymbol InterferenceIntersymbol Interference
![Page 25: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/25.jpg)
ד"ר אורי מחלב
Nyquist FilteringNyquist Filtering
Raised Cosine
![Page 26: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/26.jpg)
ד"ר אורי מחלב
Filter Coefficient & Determines Required B.W.Filter Coefficient & Determines Required B.W.
15.0
3.00
SF2SFRateSymbolFS _
Amplitude
Response
Linear Phase
(Flat Group Delay)
![Page 27: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/27.jpg)
ד"ר אורי מחלב
The Filtering is Distributed in the RadioThe Filtering is Distributed in the Radio
CO
DER MOD
UPCONVERTER
DOWNCONVERTER
DEMOD
DE C
OD
E R
![Page 28: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/28.jpg)
ד"ר אורי מחלב
SUMMARYSUMMARY
As the modulation complexity increases,the radio becomes more spectrally efficient.However, it also become more susceptibleto errors caused by noise and distortions.
![Page 29: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/29.jpg)
ד"ר אורי מחלב
TOTAL PROBABILITYOF NOISE AMPLITUDE
EXCEEDING THISTHRESHOLD
THRESHOLDP(x)
X10 20 30-10-20-30
0.1
0.2
0.3
0.4
![Page 30: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/30.jpg)
ד"ר אורי מחלב
How Error OccurHow Error OccurVOLTAGE
PROBReceived signal withsuperimposed noise
1 ERROR
0 ERROR0
1
THRESHOLDDECISION
NORMAL1 VALUE
NORMAL0 VALUE
BINARY SIGNAL + AMPLTUDENOISE FDP
![Page 31: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/31.jpg)
ד"ר אורי מחלב
Gaussian DistributionGaussian Distribution
0.1
0.2
0.3
0.4
P(x)
X10 20 30-10-20-30
NEVER RECHSZEBO
PROBABILITYDENSITY
FUNCTION
0=RMS VALUE AFTERSUBTRACTING
DC COMPONENT
![Page 32: Digital communication- student version](https://reader036.fdocuments.in/reader036/viewer/2022062301/56815cbd550346895dcabf05/html5/thumbnails/32.jpg)
ד"ר אורי מחלב
Meaning of Eye diagramMeaning of Eye diagram
Threshold