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丐亠仍亠从仂仄仄仆亳从舒亳仂仆仆亠
      亠仆仂仍仂亞亳亳

丐亠仄舒 6. 仆舒仍仂亞仂于亠 亳 亳仂于亠
         亳亞仆舒仍. 丶
弌亳亞仆舒仍 于 亠仍亠从仂仄仄仆亳从舒亳

仆舒仍仂亞仂于亠
 亠仗亠于仆亶 仗仂仂从 仗仂 t & A
 丱舒舒从亠亳亳从亳
   仄仗仍亳亟舒
   个舒亰舒
   F ()


丶亳仂于亠
 亳从亠仆亠 亰仆舒亠仆亳 仗亳亰仆舒从仂于 于 亟亳从亠仆亠
 仄仂仄亠仆 于亠仄亠仆亳
   (discrete & quantized)
 丱舒舒从亠亳亳从亳
   仆舒亠仆亳亠 仗亳亰仆舒从舒 (仂弍仆仂 仂于仆 亳/亳仍亳 舒亰)
   F ()

         Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   2
仆舒仍仂亞仂于亠 亳亞仆舒仍:
          仂仂弍亠仆仆仂亳


仂从舒
于仂仗亳亳仄亳于仂 从
仄舒仄

弌仍仂亢仆仂
舒仗仂亰仆舒于舒仆亳

亠于仂亰仄仂亢仆仂 仂仆仂亶
亠亞亠仆亠舒亳亳




          Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   3
丶亳仂于亠 亳亞仆舒仍:
           仂仂弍亠仆仆仂亳
仂仂舒 亠亞亳舒亳亳 亳
亠亞亠仆亠舒亳亳

仂亰仄仂亢仆仂
亳仗舒于仍亠仆亳 仂亳弍仂从

仂亰仄仂亢仆仂
仂仍亠亢亳于舒仆亳 仂仂礌亳
仍亳仆亳亳

亠亠从亳于仆仂
仗亠亠亟舒亳 仆亠从仂仂
于亳亟仂于 亳亞仆舒仍仂于


          Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   4
亠亠亟舒舒 亳亞仆舒仍仂于 仆舒 PHY

DD
  仂亟亳仂于舒仆亳亠                                (line coding)
AA
  仂亟仍亳                                  (modulation)
DA
  [仂亟亳仂于舒仆亳亠]                              (line coding)
  仂亟仍亳                                  (modulation)
AD
  丶                                        (ADC, modulation)
  [仂亟亳仂于舒仆亳亠]                              (line coding)


           Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   5
个舒亰 ADC

1) 个亳仍舒亳
   (filtering)
2) 弍仂从舒 (亟亳从亠亳亰舒亳)
   (sampling)
3) 于舒仆仂于舒仆亳亠 亳亞仆舒仍舒
   (quantization)
4) 仂亟亳仂于舒仆亳亠
   (coding)



        Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   6
亳仄亠: Pulse Code Modulation -
             DS0
于从 300-3400  64kbit/s DS0
G.711

1) 个亳仍舒亳 于 亟亳舒仗舒亰仂仆亠 亟仂 4从
2) 弍仂从舒: Fs=8从 (1/125仄从)  PAM
3) 于舒仆仂于舒仆亳亠: 256仂于仆亠亶
4) 仂亟亳仂于舒仆亳亠: 8弍亳  PCM




        Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   7
NB! 丼舒仂仆仂亠 仗亠亟舒于仍亠仆亳亠
               亳亞仆舒仍仂于
    礆仂亠 仗亠仂弍舒亰仂于舒仆亳亠
    个亠



    弍舒仆仂亠
    仗亠仂弍舒亰仂于舒仆亳亠 个亠




   丿亳亳仆舒 仗亠从舒 ~
    1/亟仍亳亠仍仆仂 !
       (隆, step, sin)

                  Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   8
丿舒亞 (1): 个亳仍舒亳

    丕仄亠仆亠仆亳亠 亳仍舒
    舒仂仆 亞舒仄仂仆亳从
    于 亳亞仆舒仍亠

    Low-pass (个丼):
   弌仆亳亢亠仆亳亠  从仂仄仗仂仆亠仆 
    舒仂仂亶 于亠 舒仂
    亠亰舒

   yn = 留x + (1  留)yn 1




                Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   9
丿舒亞 (2): 亳从亠亳亰舒亳. 丐

    Basic Sampling Theorem:
   Exact reconstruction of a continuous-time
    baseband signal from its samples is possible if
    the signal is bandlimited and the sampling
    frequency is greater than twice the signal
    bandwidth




    弌仗亠从 亳亞仆舒仍舒 亟仂仍亢亠仆 弍
    从仂仆亠仆仄 (亳仍舒亳)
    弌仗亠从 亟仂仍亢亠仆 仍亠亢舒 于
    仆舒舒仍仆仂亶 仂弍仍舒亳 舒仂
    亳仍亳

    丐仂亞亟舒 亟仍 Fs2fmax: ADA ok

                      Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   10
仂舒仆仂于仍亠仆亳亠 亳亞仆舒仍舒 仗仂
          丐
sinc(x) = sin(x) / (x)



if
     亠从仂仆亠仆仂亠 于亠仄
     于仂舒仆仂于仍亠仆亳
then
     丐仂仆仂亠 亟仂于仍亠于仂亠仆亳亠
     丐
 亠舒仍仆仂亳:                                               丕 仆舒: (PCM)
     仂亞舒仆亳亠仆仆仂亠 于亠仄                                     Fs = 8kHz

     舒亰仍亳仆亠 仄亠仂亟                                         result - PAM
     亳仆亠仗仂仍亳亳
             Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   11
丿舒亞 (3): 于舒仆仂于舒仆亳亠
亠仂亟 从于舒仆仂于舒仆亳
  4000 vs 256 仂亠从
  仂亞亠仆仂 从于舒仆仂于舒仆亳 (abs, rel)
  仗仂仍亰仂于舒仆亳亠 仆亠仍亳仆亠亶仆 仄亠仂亟仂于
于舒 仗仂亟仂亟舒 (Europe/US)
  = 87.6




  袖= 255




            Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   12
丿舒亞 (4): 仂亟亳仂于舒仆亳亠

 仆舒弍仂 仂亠仂于 亳 仆舒弍仂 仂于仆亠亶
亢亠仆 亳仂于仂亶 亳亞仆舒仍


仂仍亠亟仂于舒亠仍仆仂 亳仄仗仍仂于:
  A:
       礆仂亶 从仂亟 XOR 055
  :
       弍舒仆亶 从仂亟



仂亟 仆亠仂于仄亠亳仄, 仆亢仆仂 仗亠仂弍舒亰仂于舒仆亳亠!

            Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   13
仂亞仂: Pulse Code Modulation

舒 于仂亟亠:
  于从 300-3400
舒 于仂亟亠:
  丶亳仂于仂亶 亳亞仆舒仍 DS0, 亠弍ム亳亶 从舒仆舒仍舒 于 64kbit/s



舒从 仄仂亢仆仂 仄亠仆亳 亠弍亠仄
仗仂仗从仆 仗仂仂弍仆仂 从舒仆舒仍舒, 仆亠
亢亠于 仗亳 仂仄 从舒亠于仂仄?


          Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   14
DPCM

Differetial PCM
  仍 仆亳亢亠仆亳 亠弍亠仄仂亶 仗仂仗从仆仂亶
  仗仂仂弍仆仂亳 从舒仆舒仍舒  亟亞仂亶 舒仍亞仂亳仄
  从仂亟亳仂于舒仆亳 ~ 25% - 40从弍亳/

 仂亞仆仂亰亳仂于舒仆亳亠  F(k+1)=F(k)
 亳弍从亳 仗仂亞仆仂亰亳仂于舒仆亳 - 仄仂亢亠 仆亠
 于舒亳 弍亳仂于  从仂亟亳亠仄 舒仄 舒仄仗仍亳亟



          Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   15
ADPCM

    Adaptive DPCM (G.721, G.726)
    仂仍亳亠于仂 弍亳仂于 亟仍 从仂亟亳仂于舒仆亳
    仂亳弍从亳 仗仂亞仆仂亰舒 仄仂亢亠 仄亠仆
    16, 24, 32, 40从亳/

    仂亞仆仂亰 仗仂 仆亠从仂仍从亳仄 亰仆舒亠仆亳礆

    仂弍亠仆仆仂:
   仂亟亠 于从仍ム舒亠 亟亠从仂亟亠 (仂弍舒仆舒 于磶)!



              Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   16
Delta Modulation

亰仄亠仆磳 仆亠 仂仍从仂 从仂亟亳仂于舒仆亳亠
  仂亟亳仂于舒仆亳亠 仂仍从仂 仆舒仗舒于仍亠仆亳 亳亰仄亠仆亠仆亳
  丐亳仗 仂亳弍仂从:
    亰亠仆亳仂
    亰舒于亠仆亳亠 从仍仂仆舒


  仂仍亠 舒仂舒 亟亳从亠亳亰舒亳亳


  仍 亞仂仍仂舒- 32从弍亳/  于弍仂从舒  舒仂仂亶
  32从

          Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   17
亠 于舒亳舒仆 ADC

Delta-Sigma Modulation
  弌 亳仆亠亞舒亳亠亶
Variable Slope Delta Modulation
  弌 仂仍亠亢亳于舒仆亳亠仄 从亳亰仆 从仍仂仆舒 亳 亳亰仄亠仆亠仆亳亠仄
  舒亰仄亠舒 舒亞舒 (仗亠亳舒仍仆仄亳 从仂亟舒仄亳)
SB-ADPCM
  弌 舒亰弍亳于从仂亶 仆舒 仆亠从仂仍从仂 仗仂仍仂 舒仂 + ADPCM


弍舒 亰舒亟舒舒  仂从舒亳 亠弍亠仄
仗仂仗从仆 仗仂仂弍仆仂
  弌仍仂亢仆亠亠 ADA
         Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   18
?
Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU   19

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anny87

Topic06 signals

  • 1. 丐亠仍亠从仂仄仄仆亳从舒亳仂仆仆亠 亠仆仂仍仂亞亳亳 丐亠仄舒 6. 仆舒仍仂亞仂于亠 亳 亳仂于亠 亳亞仆舒仍. 丶
  • 2. 弌亳亞仆舒仍 于 亠仍亠从仂仄仄仆亳从舒亳 仆舒仍仂亞仂于亠 亠仗亠于仆亶 仗仂仂从 仗仂 t & A 丱舒舒从亠亳亳从亳 仄仗仍亳亟舒 个舒亰舒 F () 丶亳仂于亠 亳从亠仆亠 亰仆舒亠仆亳 仗亳亰仆舒从仂于 于 亟亳从亠仆亠 仄仂仄亠仆 于亠仄亠仆亳 (discrete & quantized) 丱舒舒从亠亳亳从亳 仆舒亠仆亳亠 仗亳亰仆舒从舒 (仂弍仆仂 仂于仆 亳/亳仍亳 舒亰) F () Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 2
  • 3. 仆舒仍仂亞仂于亠 亳亞仆舒仍: 仂仂弍亠仆仆仂亳 仂从舒 于仂仗亳亳仄亳于仂 从 仄舒仄 弌仍仂亢仆仂 舒仗仂亰仆舒于舒仆亳 亠于仂亰仄仂亢仆仂 仂仆仂亶 亠亞亠仆亠舒亳亳 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 3
  • 4. 丶亳仂于亠 亳亞仆舒仍: 仂仂弍亠仆仆仂亳 仂仂舒 亠亞亳舒亳亳 亳 亠亞亠仆亠舒亳亳 仂亰仄仂亢仆仂 亳仗舒于仍亠仆亳 仂亳弍仂从 仂亰仄仂亢仆仂 仂仍亠亢亳于舒仆亳 仂仂礌亳 仍亳仆亳亳 亠亠从亳于仆仂 仗亠亠亟舒亳 仆亠从仂仂 于亳亟仂于 亳亞仆舒仍仂于 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 4
  • 5. 亠亠亟舒舒 亳亞仆舒仍仂于 仆舒 PHY DD 仂亟亳仂于舒仆亳亠 (line coding) AA 仂亟仍亳 (modulation) DA [仂亟亳仂于舒仆亳亠] (line coding) 仂亟仍亳 (modulation) AD 丶 (ADC, modulation) [仂亟亳仂于舒仆亳亠] (line coding) Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 5
  • 6. 个舒亰 ADC 1) 个亳仍舒亳 (filtering) 2) 弍仂从舒 (亟亳从亠亳亰舒亳) (sampling) 3) 于舒仆仂于舒仆亳亠 亳亞仆舒仍舒 (quantization) 4) 仂亟亳仂于舒仆亳亠 (coding) Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 6
  • 7. 亳仄亠: Pulse Code Modulation - DS0 于从 300-3400 64kbit/s DS0 G.711 1) 个亳仍舒亳 于 亟亳舒仗舒亰仂仆亠 亟仂 4从 2) 弍仂从舒: Fs=8从 (1/125仄从) PAM 3) 于舒仆仂于舒仆亳亠: 256仂于仆亠亶 4) 仂亟亳仂于舒仆亳亠: 8弍亳 PCM Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 7
  • 8. NB! 丼舒仂仆仂亠 仗亠亟舒于仍亠仆亳亠 亳亞仆舒仍仂于 礆仂亠 仗亠仂弍舒亰仂于舒仆亳亠 个亠 弍舒仆仂亠 仗亠仂弍舒亰仂于舒仆亳亠 个亠 丿亳亳仆舒 仗亠从舒 ~ 1/亟仍亳亠仍仆仂 ! (隆, step, sin) Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 8
  • 9. 丿舒亞 (1): 个亳仍舒亳 丕仄亠仆亠仆亳亠 亳仍舒 舒仂仆 亞舒仄仂仆亳从 于 亳亞仆舒仍亠 Low-pass (个丼): 弌仆亳亢亠仆亳亠 从仂仄仗仂仆亠仆 舒仂仂亶 于亠 舒仂 亠亰舒 yn = 留x + (1 留)yn 1 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 9
  • 10. 丿舒亞 (2): 亳从亠亳亰舒亳. 丐 Basic Sampling Theorem: Exact reconstruction of a continuous-time baseband signal from its samples is possible if the signal is bandlimited and the sampling frequency is greater than twice the signal bandwidth 弌仗亠从 亳亞仆舒仍舒 亟仂仍亢亠仆 弍 从仂仆亠仆仄 (亳仍舒亳) 弌仗亠从 亟仂仍亢亠仆 仍亠亢舒 于 仆舒舒仍仆仂亶 仂弍仍舒亳 舒仂 亳仍亳 丐仂亞亟舒 亟仍 Fs2fmax: ADA ok Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 10
  • 11. 仂舒仆仂于仍亠仆亳亠 亳亞仆舒仍舒 仗仂 丐 sinc(x) = sin(x) / (x) if 亠从仂仆亠仆仂亠 于亠仄 于仂舒仆仂于仍亠仆亳 then 丐仂仆仂亠 亟仂于仍亠于仂亠仆亳亠 丐 亠舒仍仆仂亳: 丕 仆舒: (PCM) 仂亞舒仆亳亠仆仆仂亠 于亠仄 Fs = 8kHz 舒亰仍亳仆亠 仄亠仂亟 result - PAM 亳仆亠仗仂仍亳亳 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 11
  • 12. 丿舒亞 (3): 于舒仆仂于舒仆亳亠 亠仂亟 从于舒仆仂于舒仆亳 4000 vs 256 仂亠从 仂亞亠仆仂 从于舒仆仂于舒仆亳 (abs, rel) 仗仂仍亰仂于舒仆亳亠 仆亠仍亳仆亠亶仆 仄亠仂亟仂于 于舒 仗仂亟仂亟舒 (Europe/US) = 87.6 袖= 255 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 12
  • 13. 丿舒亞 (4): 仂亟亳仂于舒仆亳亠 仆舒弍仂 仂亠仂于 亳 仆舒弍仂 仂于仆亠亶 亢亠仆 亳仂于仂亶 亳亞仆舒仍 仂仍亠亟仂于舒亠仍仆仂 亳仄仗仍仂于: A: 礆仂亶 从仂亟 XOR 055 : 弍舒仆亶 从仂亟 仂亟 仆亠仂于仄亠亳仄, 仆亢仆仂 仗亠仂弍舒亰仂于舒仆亳亠! Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 13
  • 14. 仂亞仂: Pulse Code Modulation 舒 于仂亟亠: 于从 300-3400 舒 于仂亟亠: 丶亳仂于仂亶 亳亞仆舒仍 DS0, 亠弍ム亳亶 从舒仆舒仍舒 于 64kbit/s 舒从 仄仂亢仆仂 仄亠仆亳 亠弍亠仄 仗仂仗从仆 仗仂仂弍仆仂 从舒仆舒仍舒, 仆亠 亢亠于 仗亳 仂仄 从舒亠于仂仄? Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 14
  • 15. DPCM Differetial PCM 仍 仆亳亢亠仆亳 亠弍亠仄仂亶 仗仂仗从仆仂亶 仗仂仂弍仆仂亳 从舒仆舒仍舒 亟亞仂亶 舒仍亞仂亳仄 从仂亟亳仂于舒仆亳 ~ 25% - 40从弍亳/ 仂亞仆仂亰亳仂于舒仆亳亠 F(k+1)=F(k) 亳弍从亳 仗仂亞仆仂亰亳仂于舒仆亳 - 仄仂亢亠 仆亠 于舒亳 弍亳仂于 从仂亟亳亠仄 舒仄 舒仄仗仍亳亟 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 15
  • 16. ADPCM Adaptive DPCM (G.721, G.726) 仂仍亳亠于仂 弍亳仂于 亟仍 从仂亟亳仂于舒仆亳 仂亳弍从亳 仗仂亞仆仂亰舒 仄仂亢亠 仄亠仆 16, 24, 32, 40从亳/ 仂亞仆仂亰 仗仂 仆亠从仂仍从亳仄 亰仆舒亠仆亳礆 仂弍亠仆仆仂: 仂亟亠 于从仍ム舒亠 亟亠从仂亟亠 (仂弍舒仆舒 于磶)! Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 16
  • 17. Delta Modulation 亰仄亠仆磳 仆亠 仂仍从仂 从仂亟亳仂于舒仆亳亠 仂亟亳仂于舒仆亳亠 仂仍从仂 仆舒仗舒于仍亠仆亳 亳亰仄亠仆亠仆亳 丐亳仗 仂亳弍仂从: 亰亠仆亳仂 亰舒于亠仆亳亠 从仍仂仆舒 仂仍亠 舒仂舒 亟亳从亠亳亰舒亳亳 仍 亞仂仍仂舒- 32从弍亳/ 于弍仂从舒 舒仂仂亶 32从 Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 17
  • 18. 亠 于舒亳舒仆 ADC Delta-Sigma Modulation 弌 亳仆亠亞舒亳亠亶 Variable Slope Delta Modulation 弌 仂仍亠亢亳于舒仆亳亠仄 从亳亰仆 从仍仂仆舒 亳 亳亰仄亠仆亠仆亳亠仄 舒亰仄亠舒 舒亞舒 (仗亠亳舒仍仆仄亳 从仂亟舒仄亳) SB-ADPCM 弌 舒亰弍亳于从仂亶 仆舒 仆亠从仂仍从仂 仗仂仍仂 舒仂 + ADPCM 弍舒 亰舒亟舒舒 仂从舒亳 亠弍亠仄 仗仂仗从仆 仗仂仂弍仆仂 弌仍仂亢仆亠亠 ADA Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 18
  • 19. ? Introduction To Telecommunications 2012 - 息 Alexander Eltsov, SPbSPU 19