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Electrical Communications Systems ECE.09.433 Spring 2019

Electrical Communications Systems ECE.09.433 Spring 2019. Lecture 10a April 2, 2019. Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring19/ecomms/. Plan. Digital Baseband Communications Pulse Amplitude Modulation Sampling Quantization

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Electrical Communications Systems ECE.09.433 Spring 2019

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  1. Electrical Communications SystemsECE.09.433Spring 2019 Lecture 10aApril 2, 2019 Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring19/ecomms/

  2. Plan • Digital Baseband Communications • Pulse Amplitude Modulation • Sampling • Quantization • TDM Standards • T1 (DS-1) Line • North American TDMA Hierarchy • Line Encoding • Data Processing & Data Communications • Communications Networks • Packet Switched Networks • OSI 7-Layer Protocol Architecture • TCP-IP Protocol Architecture

  3. ECOMMS: Topics

  4. Digital Communications Transceiver Anti- aliasing Filter Error Control Encoder Data Encryption Encoder Channel/ Line Encoder Source Encoder Sampling Quantization Modulator MUX ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Error Control Decoder Data Encryption Decoder Source Decoder Audio Amp Reconstruction/ DAC Equalization / Decision Circuits Demod-ulator DEMUX

  5. Pulse Code Modulation (PCM) • Standard for all digital communications Analog Signal Sample & Hold Digital Bitstream Quantize Encode PAM PCM

  6. 8 Analog PAM 6 4 2 0 -2 -4 -6 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 time Pulse Amplitude Modulation: Flat-top Sampling Matlab Demo: pam.m

  7. Quantization Uniform Non-Uniform m-Law A-Law Mid-rise Mid-tread Matlab Demos: quantization.m pcm.m • Mid-rise • Mid-tread • Mid-rise • Mid-tread Matlab Demos: companding.m pcm_mucompand.m pcm_mucompand2.m pcm_acompand.m pcm_acompand2.m

  8. Digital Communications Transceiver Anti- aliasing Filter Error Control Encoder Data Encryption Encoder Channel/ Line Encoder Source Encoder Sampling Quantization Modulator MUX ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Error Control Decoder Data Encryption Decoder Source Decoder Audio Amp Reconstruction/ DAC Equalization / Decision Circuits Demod-ulator DEMUX

  9. Decode Time Division Multiplexing Message 1 Quantize & Encode Message 2 Channel Message N Message 1 LPF Message 2 LPF Message N LPF

  10. Channel 1 Channel 24 Channel 2 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 8 8 8 T1-Line TDM Format 1 Frame = (24 Channels + F) = 125 ms F 193 bits Frame Sync Bit Even Frames: 0 0 1 1 1 0 Odd Frames: 1 0 1 0 1 0 Every Sixth Frame LSB (8th bit) is a Signaling bit Bipolar R-Z Line Encoding

  11. 24 6 1 7 1 1 1 2 4 1 5th M U X 3rd M U X 2nd M U X 4th M U X DS-2 6.312 Mbps 96 VF DS-3 44.736 Mbps 672 VF DS-4 274.176 Mbps 4032 VF DS-1 1.544 Mbps 24 VF North American TDMA Hierarchy 64 kbps 1 VF DS-0 1st M U X DS-5 560.160 Mbps 8064 VF • Figure 3-40, p. 214 in Couch • Table 3-8, p. 215 in Couch • Table 3-9, p. 216 in Couch

  12. Digital Communications Transceiver Anti- aliasing Filter Error Control Encoder Data Encryption Encoder Channel/ Line Encoder Source Encoder Sampling Quantization Modulator MUX ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Error Control Decoder Data Encryption Decoder Source Decoder Audio Amp Reconstruction/ DAC Equalization / Decision Circuits Demod-ulator DEMUX

  13. Line Encoding Couch, p. 170 Couch, p. 165

  14. Digital Communications Transceiver Anti- aliasing Filter Error Control Encoder Data Encryption Encoder Channel/ Line Encoder Source Encoder Sampling Quantization Modulator MUX ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Error Control Decoder Data Encryption Decoder Source Decoder Audio Amp Reconstruction/ DAC Equalization / Decision Circuits Demod-ulator DEMUX

  15. Recall Message 1 Message 1 Multiplexer 2 Demultiplexer 1 2 3 1 S 2 3 S Message 2 Message 2 Message 3 Message 3 3 H H 1 Depacket-izing Message 1 2 H Message 1 3 H H 1 Depacket-izing Packetizing Message 2 Message 2 2 H 3 H Message 3 Depacket-izing H 1 Message 3 2 H Digital Communication Paradigms Circuit Switching Sync bits Packet Switching Header bits

  16. Router Router Step 1: Step 2: Step 3: …….. …….. Step 1: Step 2: Step 3: …….. …….. Protocol Protocol Message Sender Receiver Medium Communications Networking

  17. A 3-Layer Protocol Architecture Files and file transfer commands Comm related messages Comm network Computer 1 Computer 2

  18. 7 6 5 4 3 2 1 Application Presentation Session Transport Network Data Link Physical ISO OSI 7-Layer Model Please Do Not Touch Steve’s Pet Alligator

  19. TCP-IP OSI Application Application Presentation User space Session Transport (host-to-host) Software Transport Internet Network Firmware Network Access Operating system Data Link Hardware Physical Physical TCP-IP Protocol Architecture

  20. Host B TCP App Y App X Host A TCP App Y App X IP Network access protocol #2 Physical IP Network access protocol #1 Physical TCP-IP Operation Example Port or Service access point (SAP) Logical connection (TCP) Global network address Subnetwork attachment point address Logical connection Router J Network 2 Network 1

  21. User Data Application Byte Stream TCP Segment IP Datagram Network Level Packet TCP header IP header Network header TCP-IP Protocol Packet

  22. IP Header 0 4 8 16 19 31 20 octets

  23. TCP Header 0 4 10 16 31 20 octets

  24. Summary

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