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Communication systems

Communication systems. Dr. Bahawodin Baha School of Engineering University of Brighton, UK July 2007. Block diagram of a Communication System. COMMUNICATION SYSTEMS. Provide electronic exchange of multimedia data, Voice, data, video, music, email, web pages, etc.

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Communication systems

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  1. Communication systems Dr. Bahawodin Baha School of Engineering University of Brighton, UK July 2007

  2. Block diagram of a Communication System

  3. COMMUNICATION SYSTEMS • Provide electronic exchange of multimedia data, Voice, data, video, music, email, web pages, etc. • Communication Systems of today Radio and TV broadcasting, Public Switched Telephone Network (voice, fax, modem) • Cellular Phones • Computer networks (LANs, WANs, and the Internet) • Satellite systems (pagers, voice/data, movie broadcasts) • Bluetooth

  4. Provide electronic exchange of multimedia information • The information to be transmitted is electromagnetic wave or electrical signal may represent: multimedia data, Voice, data, video, music, email, web pages, etc. • The frequency bandwidth occupied by the information signal is called the baseband, and the signal is often referred to as the baseband signal. • Channel – is the medium by which the transmitted signal is propagated: • Various layers of atmosphere, cable for telephone or date link, cable TV or • Electrical signals are converted to a corresponding light signal that is propagated through a fiber optic channel

  5. Electromagnetic Spectrum

  6. Based on these conditions, the radio spectrum is divided into the following sub bands: • Extra Low Frequency (ELF) 300 – 3000 Hz (l =1000 – 100km) • Very Low Frequency (VLF) 3 – 30 kHz (l = 100 – 10 km) • Applications: mining, underwater communication (submarine), Sonar • Low Frequency (LF) 30 – 300 kHz (l = 10 – 1 km) • Applications: broadcasting, radio navigation • Medium Frequency (MF) 300 – 3000 kHz (l = 1000 – 100 m) • Applications: AM radio broadcasting (550 – 1600 kHz) • High Frequency (HF) 3 – 30 MHz (l = 100 – 10 m) • Applications: Broadcasting over large areas, amateur radio (ham), citizens band (CB) radio. • Very High Frequency (VHF) 30 – 300 MHz (l = 10 – 1 m) • Applications: TV, FM radio (88 –1108 MHz ), radio beacons for air traffic control • Ultra High Frequency (UHF) 300 – 3000 MHz (l = 1 m – 10 cm) • Applications: broadcasting, satellite (TV) broadcasting, all (1G to 3G) land mobile telephones, cordless telephones, some air traffic control. • Super High Frequency (SHF) 3 – 30 GHz (l = 10 – 1 cm) • Applications: Satellite service for telephony and TV, mobile services in the future • Extremely High Frequency (EHF) 30 – 300 GHz (l = 10 – 1 mm) • Applications: communications at short distances (within Line-Of-Sight), broadcast satellite for HDTV (for satellite communication between satellites in space, not space to earth).

  7. Communication theories • Communication systems send and receive information electronically over communication channels • Modulation • Demodulation • Amplification • Filtering • Signal detection • Digital Signal Processing, DSP

  8. Wireless Communication • Objectives: • Multimedia wireless Communications at any Time and Anywhere • Brief history • Ancient Systems: Smoke Signals, Carrier Pigeons • Radio invented in the 1880s by Marconi • Many sophisticated military radio systems were developed during and after WW2 • Cellular has enjoyed exponential growth since 1988, with more than 1 billion users worldwide today • Ignited the recent wireless revolution, 1980-2003 • Growth rate tapering off • Is there a future for wireless?

  9. Design Challenges • Hardware Design • Precise components • Small, lightweight, low power • Cheap • High frequency operations • System Design • Converting and transferring information • High data rates • Robust to noise and interference • Supports many users • Network Design • Connectivity and high speed • Energy and delay constrains

  10. Main Points • Introduction to Communication Systems • Block diagram of a Communication System • Electromagnetic spectrum • Main theories • Wireless and mobile Communications • Design challenges include hardware, system and network issues

  11. The END http://www.uobkupartnership.talktalk.net

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