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การสื่อสารข้อมูลและเครือข่ายคอมพิวเตอร์

Data Communication and Networks. การสื่อสารข้อมูลและเครือข่ายคอมพิวเตอร์. บทที่ 2 พื้นฐานข้อมูลและสัญญาณ. อาจารย์ผู้สอน : ดร.วีรพันธุ์ ศิ ริฤทธิ์. E-Mail : siririth @ gmail.com. Analog Transmission. 5.1 Modulation of Digital Data. Digital-to-Analog Conversion

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การสื่อสารข้อมูลและเครือข่ายคอมพิวเตอร์

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  1. Data Communication and Networks การสื่อสารข้อมูลและเครือข่ายคอมพิวเตอร์ บทที่ 2 พื้นฐานข้อมูลและสัญญาณ อาจารย์ผู้สอน : ดร.วีรพันธุ์ ศิริฤทธิ์ E-Mail : siririth @ gmail.com

  2. AnalogTransmission

  3. 5.1 Modulation of Digital Data Digital-to-Analog Conversion Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Quadrature Amplitude Modulation Bit/Baud Comparison

  4. Figure 5.1Digital-to-analog modulation

  5. Figure 5.2Types of digital-to-analog modulation

  6. Note: Bit rate is the number of bits per second. Baud rate is the number of signal units per second. Baud rate is less than or equal to the bit rate.

  7. Example 1 An analog signal carries 4 bits in each signal unit. If 1000 signal units are sent per second, find the baud rate and the bit rate Solution Baud rate = 1000 bauds per second (baud/s) Bit rate = 1000 x 4 = 4000 bps

  8. Example 2 The bit rate of a signal is 3000. If each signal unit carries 6 bits, what is the baud rate? Solution Baud rate = 3000 / 6 = 500 baud/s

  9. Figure 5.3ASK

  10. Figure 5.6FSK

  11. Figure 5.8PSK

  12. Note: Quadrature amplitude modulation is a combination of ASK and PSK so that a maximum contrast between each signal unit (bit, dibit, tribit, and so on) is achieved.

  13. Figure 5.17Bit and baud

  14. 5.2 Telephone Modems Modem Standards

  15. Note: A telephone line has a bandwidth of almost 2400 Hz for data transmission.

  16. Figure 5.18Telephone line bandwidth

  17. Note: Modem stands for modulator/demodulator.

  18. Figure 5.19Modulation/demodulation

  19. Figure 5.22Traditional modems

  20. Figure 5.2356K modems

  21. 5.3 Modulation of Analog Signals Amplitude Modulation (AM) Frequency Modulation (FM) Phase Modulation (PM)

  22. Figure 5.24Analog-to-analog modulation

  23. Figure 5.25Types of analog-to-analog modulation

  24. Figure 5.26Amplitude modulation

  25. Figure 5.29Frequency modulation

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