HY430 FS OS Fp 2004

1
HY430 ??F????S ???????O???SF????p??? 2004

• ?p?st???? ??a?a??t??
• tragani_at_csd.uoc.gr

2
S??p?? t?? µa??µat??

• ??sa???? st?? ?e???a t?? t??ep????????a???
  s?st?µat??.
• ?µfas? st?? µa??µat??e? te????e? ?a? st??
  ?ata???s? t?? ßas???? a????, t?? µe??d??, t??
  ?eµe???d?? pe?????sµ?? ?a? t?? trade-offs t??
  ??f?a??? s?st?µat?? ep????????a?
• eµßa???s? st?? ßas??e? f?s??e? ?????e? µe t??
  ß???e?a p??s?µ???se?? ( Matlab, SystemView)
• e?a??st? a?af??a se hardware, p??t?????a,
  ß??µ??a???a standards, p?????ta.

3
?e??e??µe?a t?? µa??µat??

• ??sa?????a, ?st????a st???e?a
• ??as??p?s? Te???a? ???a??t?t?? ?a? ?et/sµ??
  Fourier.
• S?µata ?a? s?st?µata, St??ast??e? d?ad??as?e?.
• Te???a ?????f?????, s?µp?es? s?µat??,
  ????t???t?ta ?a?a????
• ??a?????? ?a? ??f?a?? d?aµ??f?s?
• ?etad?s? pa?µ?? st?? ßas??? ????
• ??a??s? st?? ???? s?µat??. ?e?t?st?? ?e?t??
• ?etad?s? se ???? fasµat??. ?e?t?st? µ??f? pa?µ??
• ???????µ??a ?eµata Spread Spectrum, CDMA,
  Multitone Communications

4
?a???e? t?? pa????d???

• 6 ? 7 sets as??se?? µe as??se??
  ?e???t??e?-?p?????st??e? ?a? p??s?µ???se??
  s?st?µat?? ?a? d?e??as??? st? MATLAB ? st?
  SystemView (20)
• Project ?ata p??t?µ?s? µe ???s? t?? MATLAB ? t??
  SystemView (15)
• ??etas? p???d?? (20)
• ?e???? ??apt? e?etas? (45 ef ?s?? gt 4.5)

5
??sa????

• Ist????a st???e?a
• ? t??ep????????a?? d?ad??as?a
• ???ep????????a??? p????
• ?s??? e?p?µp??
• ????? ?a?a????
• ???e? p????f???a?
• ?????? t??p?? µeta?????
• ?eta???? ?????µat??
• ?eta???? pa?et??
• ?a?a??a ???ep????????a?
• ? d?ad??as?a t?? d?aµ??f?s??
• ??a?????a ?a? ??f?a?a s?st?µata ep????????a?
• ????t???t?ta ?a?a???? (Shannons channel
  capacity)
• ??a p??ß??µa ??f?a??? ep????????a?

6
Historical notes

• Telegraphy and Telephony
• 1837 Samuel Morse developed the electric
  telegraph (and some years later the well-known
  variable length binary code)
• 1858 First transatlantic cable linking US and
  Europe
• 1875 Emile Baudot developed a fixed length
  binary code (in which each letter was encoded
  using 5 bits)
• 1876 Alexander Graham Bell invented telephone
• 1915 Long distance telephone transmission was
  made possible (mainly due to the invention of
  triode amplifier in 1906). The first
  transatlantic cable for telephone services became
  available in 1953
• 1897 Strowger developed the first
  (electromechanical) automatic switch. The first
  digital switch was developed in 1960

7
Historical notes

• Wireless Communications
• 1820 Oersted demonstrated that an electric
  current produces a magnetic field
• 1831 Faraday showed that an induced current is
  produced by moving a magnet in the vicinity of a
  conductor (i.e. a changing magnetic field
  produces an electric field)
• 1867 Based on the above background Maxwell
  predicted existence of electromagnetic (EM) waves
  and formulated the basic theory
• 1887 Hertz proved existence of EM waves a
  transmitter generated a signal in a receiver
  several meters away
• 1896 Guglielmo Marconi demonstrated wireless
  telegraph to English telegraph office
• 1901 Marconi successfully transmitted radio
  signal across Atlantic Ocean from Cornwall to
  Newfoundland

8
Historical notes (cont.)

• Wireless Communications (cont.)
• 1914 First voice over radio transmission
• 1920s Mobile receivers installed in police cars
  in Detroit
• 1930s Mobile transmitters developed radio
  equipment occupied most of police car trunk
• 1935 Frequency modulation (FM) demonstrated by
  Armstrong
• 1946 First interconnection of mobile users to
  public switched telephone network (PSTN)
• 1949 FCC recognizes mobile radio as new class of
  service

9
Historical notes (cont.)

• The past fifty years
• Satellite Communications
• Optical Communications
• Cellular Mobile Communications
• From Analog to Digital Systems
• Wireless Networks
• Developments in technology (transistor, IC,
  optics, microwave generation and amplification,
  antenna technology, etc)
• Theoretical advances (Hartley, Nyquist, Wiener,
  Shannon, Hamming )

10
Historical notes (cont.)

• Frectorea The first wireless digital
  communication system
• In an early form developed before 1100 b.c.
  Gradually the system was technically improved and
  expanded covering all Greek territory
• Greek alphabet was devided in five groups of
  consecutive letters
• Relay system Two groups of torches each one
  consisting of 5 torches Number of lit torches in
  the 1st group ? i-th group of letters
  Number of lit torches in the 2nd group ? j-th
  letter of the i-th group
• The torches were always lit and they were covered
  or revealed depending on the transmitted
  character
• A message could travel a distance more then
  1000km in less than 1h
• It is interesting that the positions of the
  relay stations were approximately the same as
  those of the todays fixed wireless MW network

11
Historical notes (cont.)

• Frectorea - F???t???a

12
? t??ep????????a?? d?ad??as?a (1)

• ?? ep????????e? ep???ea???? ßa??tata t?? ??? µa?
• ?a t??ef??a sta ?e??a µa?, ta ?ad??f??a ?a? ??
  t??e??ase?? st? sa???? µa?, ?? ?/? p?? s??de??ta?
  st? Internet sta ??afe?a ?a? sta sp?t?a µa?
  ep?t?ep??? t?? ta??tat? ep????????a µe ?a?e ????a
  t?? p?a??t?.
• ?? ep????????e? ap?te???? ta a?s??t???a ???a?a
  ??a ta p???a st??? ??ea????, ??a ta ae??p?a?a
  st?? ae?a ?a? ??a ta d?ast?µ?p???a ?a? t???
  d???f????? st? d?ast?µa
• ?a ????ta t??ef??a ep?t?ep??? t?? epaf? µa? e?
  ????se? µe t? ??afe?? ?a? t? sp?t?.
• S?st?µata ep????????a? ep?t?ep??? t?? p????f???s?
  p.? t?? µete???????? ??a t?? µete??????????
  s?????e?

13
? t??ep????????a?? d?ad??as?a (2)

• ? ep????????a s???stata? st?? µetad?s?
  p????f???a? ap? e?a s?µe?? t?? ?????????? se e?a
  a???. ?e???aµßa?e? t?? e??? d?ad??as?e?.
• ?a?a???? s?µat?? p????f???a? (µ???µa)
• F???, µ??s???, e????a, ded?µe?a.
• ?a?astas? µ???µat?? µe s????? s?µß???? ?a?
  ded?µe?? a???ße?a
• ??e?t???a, a???st??a, ?pt??a
• ??d???p???s? t?? s?µß???? se µ??f? ?ata????? ??a
  µetad?s? st? ded?µe?? f?s??? µes?? (??µat?µ??fe?)
• ?etad?s? t?? ??µat?µ??f?? st?? ep???µ?t?
  p?????sµ?.
• ?p???d???p???s? ?a? a?apa?a???? t?? a??????
  s?µß????.
• ??apa?a???? t?? a?????? µ???µat?? µe µ?a
  a?ap?fe??t? a??a p???a????sµe?? ?a? e?e???µe??
  ap??e?a p???t?ta?

14
? t??ep????????a?? d?ad??as?a (3) St???e?a e???
???ep????????a??? s?st?µat??
???? p????f???a?
???st?? p????f???a?
S?µa p????f???a?
??t?µ?s? s?µat?? p????f.
T???ß?? ?a?aµ??f?s?
?a????
???t??
??µp??
??peµp?µe?? s?µa
?aµßa??µe?? s?µa
15
? t??ep????????a?? d?ad??as?a (4) ?as???? t?p??
ep????????a?

• ??p?µp? ( ????p?µp? - Broadcasting)
• ??a? ?s????? p?µp??
• ?????? ?a? f????? de?te?
• ????d??µ? ??? p????f???a? (downlink)
• ?a?a??a?? t? Multicasting (ep??e?µe??? de?te?)
• ?p????????a s?µe???-µe-s?µe?? (point-to-point)
• ??a? p?µp?? ?a? e?a? de?t??
• ?µf?d??µ? ??? p????f???a?
• ? t??ep????????a?? d?ad??as?a e??a? e? t?? f?se??
  t?? stat?st??? d?ad??as?a

16
?? ?????? t??ep????????a??? p????(a?a?a se
a?epa??e?a)

• ?s??? e?p?µp??
• ?a?a?? µe pe?????sµ? ?s???? (Power limited
  channel)
• ?.?. ????f????? ?a?a??
• ????? fasµat?? ?a?a???? µetad?s??
• ?a?a?? µe pe?????sµe?? fasµa (Bandwidth limited
  channel)
• ?.?. ???ef????? d??t??
• ?? ?????? t??ep????????a??? e?????
• ? ????ß?? st? ?a?a??
• ? pa?aµ??f?s? t?? ?a?a????
• ?e?????????? pe?????sµ??

17
?as??e? ?????e?

• ???e? ?????f???a?
• ?a?a??a ep????????a?
• ??aµ??f?s?, ????p?e??a
• ????t???t?ta ?a?a????

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???e? ?????f???a? (1)

• ?a ????a s?µata p????f???a? e??a?
• ? f??? (300 Hz 3100 Hz)
• ? µ??s??? (20 Hz 20 kHz)
• H e????a
• ???aµ???, p.?. TV (0 - 6.0 MHz)
• Stat???, p.?. Fax
• ?a ?ed?µe?a (data) p?? pa?a???? ?? ?/? ?a? a??a
  ??f?a?a s?st?µata
• ?etad?s? ?ata ??p?? (bursty)
• ?a 3 ?a? 4 e??a? s?µata e??e?a? ?????

19
???e? ?????f???a? (2)??d???p???s? p????
(s?µp?es?)

• S?µp?es? ????? ap??e?e? (lossless p.?.
  Lempel-Ziv)
• S?µp?es? µe ap??e?e? (lossy)
• JPEG standard ??d???p???s?? e??????
• MPEG-1 standard ??d???p???s?? video (1.5 Mb/s)
• MPEG-1 standard ??d???p???s?? audio (µe??? 16
  kb/s)
• MP3 MPEG-1 Layer 3 (128 kb/s)
• MPEG-2 (DVD, SVCD)
• MPEG-4 (Divx, Xdiv, quick time)
• MPEG-7

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?a?a??a ?p????????a?

• ?? ?a?a?? pa?e?e? t?? ?e??? ??µp?? - ?e?t?
• ???ß??µata
• - ?e?????sµe?? e???? fasµat??
• - ?p?sßes?, pa?aµ??f?s? p?at??? ?a? fas??
• - ??sa???? ????ß?? (Te?µ???? p??s?et????
  ?e???? ????ß??, ????st???? ????ß??, pa?eµß??e? )
• - ????ap?? d??de?s?? (as??µat? ?a?a??)
• - ??????e? µetaß??e?

21
??d? ?a?a???? ?p????????a?

• ?a?a??a ?a??d????µe??? µetad?s??
• ???ef????a ?a?a??a ( s??est?aµµ??a ?e???
  s??µat??) (f???, xDSL)
• ?µ?a?????a ?a??d?a (CATV)
• ?pt??e? ??e? (2 x 10?13 Hz)
• ?a?a??a e?e??e??? µetad?s??
• ?a?a??a ?ad??µetad?s?? (radio, TV, WLAN)
• ?a?a??a ????t?? ep????????a? (GSM, UMTS)
• ????f????a ?a?a??a
• ?a?a??a as??µat?? d??t???
• G?aµµ??a µ? ??aµµ??a
• ??????a aµetaß??ta ??????a µetaßa???µe?a
• ?e pe?????sµ? ?s???? µe pe?????sµ? fasµat??

22
??d? ?a?a???? ?p????????a?(2)

• ???ef????? ?a?a??
• ?a?a?? pe?????sµe??? e????? 300 ?z 3100 ?z
• ?e?a?? ap?sßes? st?? ?????te?e? s????t?te?
• ???p???s? µe s??est?aµµ??? ?e???? ?a??d??? (Zo
  90 110 Oµ)
• ??a??t? se ??e?t??µa???t??e? pa?eµß??e? ?a?
  s??a???ase??
• ? te???????a xDSL ???s?µ?p??e? a?ta ta ?a??d?a
• S??dese?? point-to-point
• ?µ?a?????? ?a??d??
• ??e? p??? µe?a??te?? e???? fasµat?? ( µe??? ?a? 1
  GHz)
• ???p???s? µe e?a? es?te???? ?a? e?a? ?????d????
  e??te???? a???? p?? ???????ta? µe d???e?t???? (??
  50 ? 75 Oµ)
• ???eta a??e?t??? st?? ??e?t??µa???t??e?
  pa?eµß??e?
• ?p?st????e? s??dese?? point-to-point a??a ?a?
  point-to-multipoint (MA)
• ???s?µ?p??e?ta? st?? ?a??d?a?? t??e??as? (CATV)
  ??a t?? µetad?s? t??e?pt???? ?a? ?ad??f??????
  p????aµµat??, ?a??? ?a? t?? INTERNET

23
?µ?a?????? ?a??d??
S??µat??? p?e?µa
???te???? pe??ß??µa
?a??d?? µetaf??a? s?µat??
????s?
24
??d? ?a?a???? ?p????????a?(3)

• ?pt??e? ??e?
• ???at?t?ta ??a te?ast?? e???? fasµat?? (µe???
  2x10?13 ?z)
• ????? ap?sßes? ?ep????????e? µe?a??? ap?stase??
• ?p?te?e?ta? ap? e?a ?a???? ?e?t???? p????a
  pe??ßa???µe?? ap? epe?d?s? µe d?af??et???
  d???e?t???? sta?e?a ?a? e?a p??state?t???
  e??te???? st??µa
• ??a?s??s?a st?? ??e?t??µa???t??e? pa?eµß??e?
• ????? µe?e??? ?a? ßa???, a??e?t???t?ta, e?e????a
• ??e?a?t??t? p??t? ??? (aµµ??)
• ?s??µata ?a?a??a e?p?µp?? ?ad??-t??e?pt????
  p????aµµat??
• ????? fasµat?? a?a???? t?? s?µat?? ?a? t??
  d?aµ??f?s??
• 20 ?hz AM (??aµ??f?s? p?at???)
• 100 ? 200 Khz FM (??aµ??f?s? s????t?ta?)
• 4 6 Mhz TV
• ?pe?ete??d???? de?te? ap?d?aµ??f?s??
• ?e?a?e? se ???a s?µe?a, ?s????? p?µp??, f?????
  ?a? ap??? de?te?
• ?p????????a µe?a??? ap?stase?? ( a?a??as?,
  pe????as?)

25
??d? ?a?a???? ?p????????a?(4)

• ?a?a??a ????t?? ep????????a?
• ?p??e?a ?a?a??a as??µat?? ep????????a? µe
  ????t??? p?µp??? ?a? de?te?
• ?e? e??a? pa?t?te d??at? ? ?pt??? epaf? p?µp??
  ?a? de?t?
• ????a??? fa???µe?? ? S????S? t?? ?/? ??µat?? ?
  p???ap?? d??de?s?
• ?? ?a?a?? ?e??e?ta? ??aµµ??? ??????a
  µetaßa???µe??
• ????f????a ?a?a??a
• ?e?a?? e???? fasµat?? (a?ta???????ta? t?? ?pt??e?
  ??e?)
• ?a???? p??? µe?a??? pe?????? t?? G?? (se
  ?e?stat??? t????a 22.300 mi)
• ?e?a?? a???p?st?a
• S??dese?? point-to-point, point-to-multipoint ?a?
  broadcasting
• ?????µe??? ? sta?e??? p?µp?? ?a? de?te?
• ???p???s? d??t??? VSAT (very small aperture
  terminals ) HUBs
• S?????? s????t?ta ?e?t?????a? ta 4/6Ghz µe t?p???
  e???? fasµat?? 500?hz d?aµ???asµe?? se 12
  transponders (36 Mhz)
• O transponder µp??e? ?a ?p?st????e? 1200 ?a?a??a
  f???? ? 50 ?bps data

26
?/? fasµa - ?e?a?e?
?c/f ?p?? c 300.000 km/sec
27
Fasµata µe????? ?????? s?µat??
F???
?/4 75 km
???s???
?/4 7.5 km
Ethernet (10 Mbps)
?/4 7.5 m
28
?a?at???se?? ??a t?? ?e?a?e?

• ???fa???, ta p??????µe?a s?µata de? µp????? ?a
  efa?µ?s???? ?ate??e?a? se ?e?a?a t? apa?t??µe??
  µ???? e??a? te?ast??
• G?a ?a ?pe?????s??µe a?t?? t?? pe?????sµ?
  µp????µe ?a ???s?µ?p???s??µe t? s?µa p????f???a?
  m(t) ??a ?a d?aµ??f?s??µe e?a fe??? ??????
  s????t?ta? fc (Radio Frequency), ets? ?ste ??
  apa?t??µe?e? d?astase?? t?? ?e?a?a? (?/4) ?a
  e??a? ?????e?.
• ??? ?e?t?????a a?t? t?? e?te?e? ? d?aµ??f?t??

29
? d?ad??as?a t?? ??????FOS?S

• ??????FOS? (Modulation) ? µetaß???, s?µf??a µe
  t? s?µa p????f???a?, t?? pa?aµet??? e??? fe???t??
  ??µat?? (carrier wave) p?? e??a? ?ata????? ??a
  t?? µetad?s? µesa ap? t? ded?µe?? ?a?a??
• ?????????FOS? (Demodulation) e??a? ? a?t?st??f?
  d?ad??as?a
• ?? e?d?? t?? d?aµ??f?s?? ?a?????e?
• ??? a?t??? st? ????ß? ?a? t?? pa?aµ??f?s? t??
  ?a?a????
• ??? p?st?t?ta a?apa?a????? t?? a?????? s?µat??
  p????f???a?
• ?? e???? t?? apa?t??µe??? ??a t?? µetad?s?
  fasµat??
• ??? p???p????t?ta t?? s?st?µat?? e?p?µp?? ?a?
  ?????

30
?? ep?t???a???µe µe t?? ??aµ??f?s?

• ??? µetad?s? p????? s?µ?t?? st?? ?d?? ???? µe
  ???s? d?af??et???? fe???t??
• ??? e?att?s? t?? apa?t?se?? sta ?a?a?t???st??a
  t?? s?st?µat?? e?p?µp??
• ??? e?µeta??e?s? pe?????? t?? fasµat?? p?? e????
  ?a???te?e? s?????e? µetad?s??

31
??d? ??aµ??f?s???µ?t???e?de? fe???

• ??aµ??f?s? s??e???? ??µat?? (continuous wave CW)
• ?? fe??? e??a? e?a ?µ?t???e?de? s?µa
  x(t)Acos(2pf t f)
• ??aµ??f?s? p?at??? (??) a? ?
  ?m(t)
• ?p?? m(t) e??a? t? s?µa p????f???a?
• ??aµ??f?s? s????t?ta? (FM) a? f
  fm(t)
• ??aµ??f?s? fas?? (PM) a? f
  fm(t)
• ??f?a?? d?aµ??f?s? s??e???? ??µat??
• ?? fe??? e??a? e?a ?µ?t???e?de? s?µa
  x(t)Acos(2pf t f)
• ?? s?µa p????f???a? e??a? µ?a a???????a pa?µ??
• ?a?µ??? d?aµ??f?s? p?at??? (ASK)
• ?a?µ??? d?aµ??f?s? s????t?ta? (FSK)
• ?a?µ??? d?aµ??f?s? fas?? (PSK)

32
??d? ??aµ??f?s???a?µ??? fe???

• ??a?????? d?aµ??f?s? pa?µ?? ( Analog pulse
  modulation)
• ?? fe??? e??a? µ?a a???????a pa?µ??
• ??aµ??f?s? ????? pa?µ?? (PAM Pulse Amplitude
  Modulation)
• ??aµ??f?s? d?a??e?a? pa?µ?? (PWM Pulse Width
  Modulation)
• ??aµ??f?s? ?es?? pa?µ?? (PPM Pulse Position
  Modulation)
• ??f?a?? d?aµ??f?s? pa?µ?? (Digital Pulse
  Modulation)
• ?? s?µa p????f???a? e??a? µ?a a???????a d?ad????
  pa?µ??
• ?a?µ???d??? ??aµ??f?s? (PCM Pulse Code
  Modulation)
• A/D µetat??p? ?e??µat?????a, ?ßa?t?sµ?? ?a?
  d?ad??? ??d???p???s?.
• Sfa?µata de??µat?????a? ?a? ?ßa?t?sµ??

33
??d? ??aµ??f?s??
?µ?t???e?de? fe???
?a?µ??? fe???
??a?????? s?µa ??ad??? s?µa
??a?????? s?µa ?ßa?t?sµe?? s?µa
p????f???a? p????f???a?
p????f???a? p????f???a?
?? FM PM ASK FSK PSK PAM
PWM PPM PCM DM
AAmplitude, FFrequency, PPhase, M
Modulation KKeying

WWidth, PPulse, Position

DDelta
x(t)S ?kp(t-tk)
x(t)Acos(2pftf)
34
?as???? t?p?? a?a??????? d?aµ??f?s??
??aµ??f?µe?? s?µa
m(t)
S?µa p????f???a?
? st??µ?a?a s????t?ta f(t) t?? cos f(t) ?at?
t?? st??µ? t e??a? ? f(t) (1/2p) df(t)/dt
?p?te
35
?as???? t?p?? ??f?a??? d?aµ??f?s??
ASK FSK PS?
36
?as???? t?p?? ??f?a??? d?aµ??f?s??

• Amplitude Shift Keying (ASK)
• Phase Shift Keying (PSK)
• Frequency Shift Keying (FSK)

37
Analog vs Digital Modulation

• ??a?????? d?aµ??f?s?
• ?? s?µa m(t) e??a? a?a??????
• ? ap?d?aµ??f?t?? p?epe? ?a a?apa?a?a?e? t? m(t)
• ?s? ?a???te?a µp??e?

38
Analog vs Digital Modulation

• ??f?a?? d?aµ??f?s?
• ?? m(t) pa???e? µ?a t?µ? ap? e?a pepe?asµe??
  s????? t?µ??
• ? ap?d?aµ??f?t?? p?epe? ?a ap?fas?se? p??a ap?
  t?? p??a?e?
• t?µe? e?e? µetad??e? de? ?pa??e? a?a???
  p?st??
• a?apa?a????? t?? m(t)

39
G?at? ??f?a?a S?st?µata?
AMP
AMP
AMP
OUTPUT
INPUT
??a??????? epa?a??pte? ? ????ß?? s?ss??e?eta?
Repeater
Repeater
Repeater
INPUT
??f?a??? epa?a??pte? ?e?e?a a?apa?a???? t??
s?µat??
40
???t???a ep?d?se??

• ??a?????a S?st?µata ?p????????a?
• ???t???? e??a? ? p?st?t?ta µetad?s??
• St???? ?aµßa??µe??e?peµp?µe?? s?µa
• ??f?a?a S?st?µata ?p????????a?
• ???t???a e??a? ? ???µ?? µetad?s?? (R bps) ?a? ?
  p??a??t?ta sfa?µat?? e??? bit ( Pbp(br?bt) )
• ?e ?da???? ?a?a?? ?a? ????? ????ß? de? e???µe
  sfa?µata.
• ?e ????ß?, ? Pb e?a?tata? ap? t? ?s?? t?? s?µat??
  ?a? t?? ????ß??, ap? t?? ???µ? µetad?s?? ?a? ta
  ?a?a?t???st??a t?? ?a?a????.

41
S?????s? ap?d?aµ??f?t?? ??a ??, FM, PM ?a?
ASK, FSK, PSK

• ?? ap?d?aµ??f?te? ??a AM, FM ?a? ??
• ??apa?a???? p?sta t? m(t) ap? t? d?aµ??f?µe??
  fe???
• ???t???? ep?t???a? ? s?µat?????ß??? s?es? SNR
• ?? ap?d?aµ??f?te? ??a ASK, FSK ?a? PSK
• ?p?fas????? ??a t? p??a ap? t?? ? d??ate?
  ??µat?µ??fe? e?e? µetad??e?
• ????? sa? e??d? t?? ??d??? t?? ??µat?µ??f?? a?t??
• ???t???? ep?t???a? ? µ???? p??a??t?ta sfa?µat??

s(t)n(t)
m(t)nout(t)
?p?d?aµ??f?t??
?p????? p??a??te??? ??µat?µ??f??
s(t)n(t)
?p?????sµ?? ??d???? ??µat?µ??f??
42
????p?e??a

• ??t?? ap? t?? d?e??????s? st?? µetad?s? ?
  d?aµ??f?s? ep?t?epe? t?? ta?t?????? µetad?s?
  p????? s?µat?? p????f???a? µesa ap? t? ?d??
  ?a?a?? (p???p?e??a). ?pa????? 3 t??p??
  p???p?e??a?
• ????p?e??a st?? s????t?ta (FDM Frequency
  Division Multiplexing). ?a?e s?µa p????f???a?
  ???s?µ?p??e? d?af??et??? ???? s????t?t??
• ????p?e??a st?? ????? (TDM Time Division
  Multiplexing). ?a?e s?µa p????f???a? ?ata?aµßa?e?
  d?af??et??? ?????s??sµ?.
• ????p?e??a µe ??d??a (CDM Code Division
  Multiplexing). ?a?e s?µa p????f???a? d?a?????eta?
  ap? ta a??a µe e?d??? ??d??a
• ????p?e??a µe d?a??es? µ????? ??µat?? (WDM-
  Wavelength Division Multiplexing). ???f? t?? FDM
  µe efa?µ??? st?? ?pt??e? ??e?.

43
???ep????????a?a S?st?µata

• ?ata t?? s?ed?as? e??? t??ep????????a???
  s?st?µat?? d?d??ta?
• ? p??? t?? p????f???a?
• ?? ?a?a?? µetad?s??, ?a?
• ? p?????sµ?? t?? p????f???a? (? te????? ???st??)
• ?a? ??te?ta? ? s?ed?as? t?? p?µp?? ?a? t?? de?t?
  µe t??p? ?ste
• ?a ???eta? ? ??d???p???s?/d?aµ??f?s? t?? s?µat??
  p????f???a? p?? pa?a?e? ? p???,
• ?a e?peµpeta? t? d?aµ??f?µe?? s?µa µesa ap? t?
  ?a?a??,
• ?a pa?a?eta? µ?a e?t?µ?s? t?? s?µat?? p????f???a?
  ?ata t??p? ??a??p???t??? ??a t?? te???? ???st?
• ?a ?????ta? ??a ta p?? pa?? ?ata t??
  ??????µ???te?? ?a? ta??te?? t??p?

44
??f?a?a ???ep????????a?a S?st?µata
???? p????f???a?
??????sµ?? ?????f???a?
S?µa p????f???a?
??t?µ?s? t?? s?µat?? p????f???a?
??d???p???t?? p????
?p???d???p???t?? ?????
?e?? ??d??a p????
??d???p???t?? ?a?a????
?p???d???p???t?? ?a?a????
?e?? ??d??a ?a?a????
??aµ??f?t??
?p?d?aµ??f?t??
?aµßa??µe?? s?µa
??peµp?µe?? ??µat?µ??f?
?a?a??
45
??f?a?a ???ep????????a?a S?st?µata(?ept?µe?este?a
)
46
?as??e? d?e??as?e? epe?e??as?a? s?µat?? se
t??ep????????a?a s?st?µata

• ???f?p???s? ?a? ??d???p???s? p????
• ??aµ??f?s? ßas???? ?????
• ??aµ??f?s? ????? fasµat??
• ???s????p?s? ?a?a????
• ??d???p???s? ?a?a????
• ????p?e??a ?a? p???ap?? p??spe?as?
• ??asp??a fasµat??
• ???pt?p??stas?a
• S???????sµ??

47
S?????s? ??a??????? ?a? ??f?a??? s?st?µat??
?p????????a?

• ??a?????a S?st?µata
• ?p???ste?? d?µ?
• ??s????te?? s?ed?as?
• ??a??ste? d??at?t?te? ???p???s?? ße?t?st??
  d?ata?e??
• ??s????te?? ???p???s? ?a? s??t???s?
• ?????? s??e??? ???µ?se??
• ?pa?t?se?? ??aµµ???t?ta? e?a?t?µat??
• ??a?t?s? ap? t?? ?e?µ???as?a?e? µetaß??e? t??
  e?a?t?µat??
• ??a?t?s? ap? t?? ???a?s? t?? ??????
• ???s?µ?p?????ta? ??a ???p???s? s?st?µat?? p???
  ?????? ta??t?t?? ? p??? µ????? ?ata?a??s??

• ??f?a?a S?st?µata
• ????p????te?? d?µ?
• ??????te?? s?ed?as?
• ???at?t?ta ???p???s?? ße?t?st?? d?ata?e??
• ??????te?? ???p???s? ?a? s??t???s?
• ?a??te?? p??sa?µ??? p??? t? ?a?a??
• ??e????a ?atas?e???
• DSPs, µPs
• FPGAs, ASICs
• ?????te?? ??st??

48
????t???t?ta ?a?a????

• ??a t??ep????????a?? s?st?µa p?epe? ?a µetafe?e?
  t? µ???µa t?? p???? st?? p?????sµ? t?? µesa ap?
  ded?µe?? ?a?a??
• a???p?sta, ?a?
• ap?te?esµat??a
• ?p? t??? pe?????sµ???
• t?? ep?t?ep?µe??? ?s???? e?p?µp??
• t?? d?a?es?µ?? e????? fasµat??, ?a?
• t?? a?e?t?? ??st??? ?atas?e??? t?? s?st?µat??
• ?et?? t?? a???p?st?a? e??a? ? ???µ?? sfa?µat??
  BER (Bit Error Rate) ? ? p??a??t?ta sfa?µat??
  e??? bit.
• ?p???µ?t? t? BER0 ? t???a??st?? BERmin
• ??O???? e??a? d??at? ? s?ed?as? e???
  t??ep????????a??? s?st?µat?? p?? ?e?t????e? µe
  BER0 a??µa ?a? pa?? ap? ?a?a?? µe ????ß???

49
Te???µa t?? Shannon????t???t?ta ?a?a????

• ?st? ? Bandwidth d??.t? e???? fasµat?? t??
  ?a?a????, ?a?
• SNR Signal-to-noise-ratio d??. ? ????? t??
  ?s???? t?? s?µat?? ?? p??? t?? ?s?? t?? ????ß??.
• ? ????t???t?ta t?? ?a?a???? C, d??ad? ? µe??st??
  ???µ?? µetad?s?? ded?µe??? (bps) ????? sfa?µa
  e??a?
• C ? log2(1 SNR) bps
• ? s??s? de???e? ?t? ??a ?a e???µe ded?µe??
  ????t???t?ta µp????µe ?a e?att?s??µe t?? ?s??
  a??a???ta? t? e???? fasµat??
• ?? R bps ? ???µ?? µetad?s?? ded?µe??? ?a? C ?
  ????t???t?ta t?? ?a?a???? t?te µp????µe ?a e???µe
  a???p?st? µetad?s? ef ?s??
• R lt C

50
??a t?p??? t??ep????????a?? p??ß??µa

• ?? s?µa t?? p???? e??a? µ?a t??a?a a???????a
  ?s?p??a??? d?ad???? s?µß???? 1 ?a? 0. ?? 1
  pa??sta?eta? µe ??e?t???? s?µa t?µ?? 1 d?a??e?a?
  ? sec. ?a? t? 0 µe t?µ? 1. ?ts? pa?a?eta? t?
  s?µa p????f???a? m(t).
• G?a ?a µetad??e? µesa ap? e?a ?a?a??
  ???s?µ?p????µe e?a ap?? t?p? d?aµ??f?s?? ???st?
  sa? PSK Phase Shift Keying.
• S?µa ?????f???a?
  ? A cos(2pft) ??a t? s?µß??? 1
• m(t) s(t) ?
• 
  
  ? -? cos(2pft) ??a t? s?µß??? 0
• ??a 0 ? t ? T
• ?? ?a?a?? ?e??e?ta? ????? pa?aµ??f?s? a??a µe
  ????ß?
• ??peµp?µe?? s?µa
  ???d?? ?a?a????
• s(t)
  r(t) s(t) n(t)
• T???ß?? n(t)

s(t) ??peµp?µe?? s?µa

X
F???? Acos(2pft)

51
??a t?p??? t??ep????????a?? p??ß??µa

• ? de?t?? ap?te?e?ta? ap? e?a correlator
  (s?s?et?st?) a????????µe?? ap? µ?a µ??ada
  ap?fas??
• correlator
• ?aµßa??µe?? yT 1 a? yT gt 0
• S?µa r(t)
• 0 a?????
• ??p??? fe??? ?at?f?? 0
• cos(2pft)
• ? T
  
  ? A/2 nT ??a t? 1
• ????µe yT ? r(t) cos (2pft) dt ? m(t) A cos
  (2pft)n(t) cos(2pft)dt ?
• 0 0
  ? - A/2
  nT ??a t? 0
• ?? e???? fasµat?? W t?? m(t) e??a? a?t?st??f??
  a?a???? t?? ?, d??. a?a???? t?? ???µ?? pa?a?????
  s?µß???? R1/T. To fasµa p?? ?ata?aµßa?e? t?
  e?peµp?µe?? s?µa s(t) e??a? pe????? e????? 2W
  ???? ap? t?? s????t?ta f . ???ad? t? apa?t??µe??
  e???? ?a?a???? e??a? BW2W ? 2R2/T

???t? ap?fas??
T ?(.)dt 0
?
m(t) 0 ? 1 ?a? (cosf)2(1/2) (1/2)cos2f
52
???t?µata s?et??a µe t? pa?ade??µa

• Te???t??a e??t?µata
• G?a p??? ???? ? de?t?? e?e? t?? µ??f? p??
  de??aµe?
• ???a e??a? ta stat?st??a ?a?a?t???st??a t??
  t??a?a? µetaß??t?? nT ?
• ? ded?µe??? de?t?? ?a?e? µe???e? f??e? sfa?µa.
  ???a e??a? ? p??a??t?ta ?a ?a?e? sfa?µa st??
  e?t?µ?s? e??? bit?
• ??a?t??a e??t?µata (s?et??a µe t?? ???p???s?)
• ?? e???? fasµat?? e??a? e?a? p???t?µ?? p????. ???
  ep??e???µe t?? d?aµ??f?s? ?ste ?a ?a???µe t??
  ße?t?st? ???s? t???
• ?? s?µa p????f???a? m(t) µp??e? ?a pe??e?e?
  p?e??asµ? s?µß???? p?? e?sa???ta? µe t??
  ??d???p???s? ?a?a???? ??a t?? a?t?µet?p?s? t??
  ????ß??. ??? p?epe? ?a s?ed?as?e? ? ??d???p???t??
  ?a? ? ap???d???p???t?? ?a?a???? ?ste ?a
  ep?t????µe ???µ? µetad?s?? p?? ?a p??s?a?e? t??
  ????t???t?ta t?? ?a?a?????
• ? t?p???? ta?a?t?t?? st?? de?t? ß??s?eta? µa???a
  ap? t?? p?µp? a??a ? ??µat?µ??f? t?? p?epe? ?a
  e??a? s???????sµe?? µe t? fe???. ???
  ep?t???a?eta? a?t?? ? s???????sµ????