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

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 4-Feb-19 NSS / MEC

Wireless Communication 4-Feb-19 NSS / MEC

Wireless Communication is an exchange of information from a sender to receiver using electromagnetic spectrum of specific frequency range. 4-Feb-19 NSS / MEC

Electromagnetic Spectrum 4-Feb-19 NSS / MEC

EM Spectrum 4-Feb-19 NSS / MEC

EM Spectrum (contd..) 4-Feb-19 NSS / MEC

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. 4-Feb-19 NSS / MEC

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 … 4-Feb-19 NSS / MEC

Modulation Process 4-Feb-19 NSS / MEC

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. 4-Feb-19 NSS / MEC

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 4-Feb-19 NSS / MEC

Analog Modulation Schemes 4-Feb-19 NSS / MEC

Applications of Analog Modulation Schemes S.No. Type of AM Signal Applications 1 AM MW (526.5 KHz to 1606.5 KHz) SW (2.3 MHz to 26.1 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 4-Feb-19 NSS / MEC

AM – SW bands 4-Feb-19 NSS / MEC

FM Modulation Schemes 4-Feb-19 NSS / MEC

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 4-Feb-19 NSS / MEC

Pulse Modulation Schemes 4-Feb-19 NSS / MEC

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 4-Feb-19 NSS / MEC

Digital Modulation Techniques 4-Feb-19 NSS / MEC

Digital Modulation Techniques 4-Feb-19 NSS / MEC

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 4-Feb-19 NSS / MEC

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) 4-Feb-19 NSS / MEC

A/D conversion of Base band Signals Audio: 20 Hz to 20000 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 4-Feb-19 NSS / MEC

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 4-Feb-19 NSS / MEC

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 4-Feb-19 NSS / MEC

Thank You for your PATIENCE. 4-Feb-19 NSS / MEC