1. Applications of Analog and Digital Communication
Dr. N.Shanmugasundaram
Professor, ECE Department
Sri Eshwar College of Engineering
Coimbatore

2. Overview of Presentation
Wireless Communication & Electromagnetic Spectrum
Modulation Process and its Types
Applications of Analog Modulation Schemes
Applications of Pulse Modulation Schemes
Applications of Digital Modulation Schemes
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3. Wireless
Communication
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4. Wireless Communication
is an exchange of information from a sender to receiver using electromagnetic spectrum of specific frequency range.
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5. Electromagnetic Spectrum
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6. EM Spectrum
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7. EM Spectrum (contd..)
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8. Why Wireless Communication?
Wireless is now cheaper to install (it will be 20% of the cost of the wired system in 2020)
Rapid deployment
Wire crack or failures requires High maintenance.
Flexibility in placement.
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9. Fundamentals of Wireless Communication
Electromagnetic Spectrum: ( 3 MHz to 300 GHz )
Propagation Mechanisms: Reflection, Diffraction & Scattering
Fading, Doppler Shift, Path Loss ( Pr = Pt.Gt.Gr. (λ / 4πd)2 )
Modulation Techniques: Analog: AM, FM Digital: ASK, FSK, BPSK, ..
Multiple Access Techniques: FDMA, OFDM, TDMA, CDMA (DSSS/FH)
Voice Coding: PCM, Vocoders, etc.
Error Control: Parity Check, Hamming Code, CRC, Convolutional code,
Turbo codes …
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10. Modulation
Process
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11. Modulation Process (Analog or Pulse) (Analog or Digital)
Modulation is the process of translating the information in message signal to carrier signal for the sake of long distance communication.
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12. Types of Modulation Schemes
S.No.
Message
Carrier
Modulated Signal 1
Analog
AM, PM, FM 2
Pulse
PAM, PWM, PPM 3
Digital
ASK, PSK, FSK
Below scheme is the process of converting a baseband signal into encoded digital signal (also called Source Encoding)
S.No.
Message
Carrier
Modulated Signal 1
Analog -
PCM, DPCM,
DM, ADM
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13. Analog Modulation Schemes
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14. Applications of Analog Modulation Schemes
S.No.
Type of AM Signal
Applications 1 AM
MW (526.5 KHz to KHz)
SW (2.3 MHz to MHz) 11 bands 2
AM – DSB / SC -- 3
AM - SSB
Walkie Talkie 4
AM - VSB
Video Transmission in TV Channels
VHF (54 MHz to 216 MHz)
UHF (470 MHz to 8980 MHz)
Undesirable Phenomenon: Combining effect by two AM signals
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15. AM – SW bands
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16. FM Modulation Schemes
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17. Applications of FM Modulation Schemes
S.No.
Type of FM Signal
Applications 1
FM / WBFM
Radio (88 to 108 MHz)
Audio in TV channels
Audio Recording 2
NBFM
Walkie Talkie
Interesting Phenomenon: Capture effect in FM reception
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18. Pulse Modulation Schemes
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19. Applications of Pulse Modulation Schemes
S.No.
Type of Pulse Modulated Signals
Applications 1
PAM
1. Data communication (in Ethernet based LAN)
Drivers for LED lighting
Digital Television 2
PWM
1. DC / Servo Motor control
Telecommunications
Voltage Regulators / Inverters 3
PPM
1. Non-coherent detection in Digital Rxs
Remote control
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20. Digital Modulation Techniques
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21. Digital Modulation Techniques
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22. Applications of Digital Modulation Techniques
S.No.
Type of Digital Modulated Signal
Applications 1
ASK
Optical Communication 2
QAM
BW efficient Digital telecomm 3
FSK
Amateur Radio 4
GMSK
GSM 5
BPSK
CDMA 6
PSK & its types
RF-ID, WLAN, Bluetooth,
ZigBee, Optical Communication
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23. Digital Modulations
Digital transmission of Analog data involves the process of converting analog data into digital signal.
It involves the process of Sampling and Quantization.
The different types of Digital Modulations are
Pulse Coded Modulation (PCM)
Differential Pulse Coded Modulation (DPCM)
Delta Modulation (DM)
Adaptive Delta Modulation (ADM)
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24. A/D conversion of Base band Signals
Audio: 20 Hz to Hz (includes speech and music)
Voice: 300 Hz to 4000 Hz
Video: 100 Hz to 5 MHz
Sampling Rate: Fs > 2 Fm (Nyquist Rate)
Quantization: No. of bits / Sample (Eg. 4, 8, 16, 24, 32…)
Sample Digital conversion of Voice Signal
8000 samples x 8 bits / sample = 64 Kb / sec
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25. Types of Digital Modulations (PCM)
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications
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26. Types of Digital Modulations (DM)
A Delta modulation (DM or Δ-modulation) is an analog-to-digital signal conversion technique used for transmission of voice information where quality is not of primary importance.
Applications of Delta Modulation includes, but is not limited to, recreating legacy synthesizer waveforms
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27. Thank You
for your PATIENCE.
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