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Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
Introduction to Communication System
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Introduction to Communication System

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A communication system is for transmitting and receiving the information that users want to exchange. To make up a communication system, we can adopt the FDMA, TDMA, CDMA, and so on. In this …

A communication system is for transmitting and receiving the information that users want to exchange. To make up a communication system, we can adopt the FDMA, TDMA, CDMA, and so on. In this presentation, we introduce a simplified communication blocks with which we can understand a modern system.

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  • 1. Electronic Circuit Design CHO, Yong Heui Introduction to Communication System
  • 2. 1. Communication Transmission  <ul><li>Information </li></ul><ul><ul><li>Channel bandwidth </li></ul></ul><ul><ul><li>Base band </li></ul></ul><ul><ul><li>Inefficient wave radiation </li></ul></ul><ul><li>Modulation – center frequency </li></ul>Time domain Frequency domain 출처 : RFDH.com
  • 3. Why do we need modulation?  <ul><li>Transmission efficiency </li></ul><ul><ul><li>Multiplexing </li></ul></ul><ul><ul><li>Antenna length: wavelength </li></ul></ul><ul><ul><li>Wave radiation: comparison with DC </li></ul></ul>Battery: DC Antenna: AC 1. Communication
  • 4. Communication transmitter (Tx)  <ul><li>Up-conversion: frequency </li></ul> 출처 : RFDH.com 1. Communication
  • 5. Communication receiver (Rx)  <ul><li>Down-conversion: frequency </li></ul> 출처 : RFDH.com 1. Communication
  • 6. Communication transceiver  <ul><li>Duplexer: bandpass filter or switch </li></ul><ul><ul><li>Loss, tx suppression, channel selection </li></ul></ul>IF: superheterodyne No IF: direct conversion 출처 : RFDH.com 1. Communication
  • 7. FDMA (FDM Access)  <ul><li>Resource: frequency </li></ul><ul><li>Guard band </li></ul><ul><li>Simple transceiver </li></ul><ul><li>Interference </li></ul>1. Communication
  • 8. TDMA (TDM Access)  <ul><li>Resource: time </li></ul><ul><li>Guard time </li></ul><ul><li>Complicated transceiver </li></ul>1. Communication
  • 9. Synchronization of TDMA  <ul><li>Guard time: imperfect sync </li></ul>1. Communication
  • 10. GSM TDMA  <ul><li>Global System for Mobile Communication </li></ul><ul><li>TDMA within FDMA </li></ul><ul><li>Carrier separation: 200 kHz </li></ul>1. Communication
  • 11. FH(Frequency Hopping)-CDMA  <ul><li>Resource: code </li></ul><ul><li>Precise clock </li></ul><ul><li>Very complicated transceiver </li></ul><ul><li>Bluetooth, military applications </li></ul>1. Communication
  • 12. DS(Direct Sequence)-CDMA QPSK: Quadrature Phase Shift Keying 1. Communication
  • 13. Block diagram of cellular phone <ul><li>LNA (Low Noise Amplifier), PA (Power Amplifier), Mixer, VCO, switch </li></ul><ul><li>Filter, duplexer </li></ul> 2. System
  • 14. Digital RF system Transmitter and receiver  2. System
  • 15. AM receiver  <ul><li>Envelope detector </li></ul>Antenna + BPF + diode + capacitor + speaker 2. System
  • 16. AM receiver with amplifier  2. System

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