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COMM 180 – SURVEY OF BROADCASTING AND CABLE

COMM 180 – SURVEY OF BROADCASTING AND CABLE Dr. George W. Crawford CURRENT ASSIGNMENT Continue reading Chapter 3 Write a paragraph summarizing the discussion that your group had on analog technology. We will cover pages 59 to 68 today. AUDIO AND VIDEO TECHNOLOGY Quick Facts:

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COMM 180 – SURVEY OF BROADCASTING AND CABLE

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  1. COMM 180 – SURVEY OF BROADCASTING AND CABLE Dr. George W. Crawford

  2. CURRENT ASSIGNMENT • Continue reading Chapter 3 • Write a paragraph summarizing the discussion that your group had on analog technology. • We will cover pages 59 to 68 today.

  3. AUDIO AND VIDEO TECHNOLOGY • Quick Facts: • Human ear can hear: 40 to 12000 HZ • Compact disc: 20 to 20000 HZ

  4. STEPS IN SIGNAL PROCESSING • Steps In Signal Processing: • Signal Generation • Amplification/Processing • Transmission • Reception • Storage and Retrieval

  5. STEP 2: Amplification/Processing • Is Transduction: • Changing from one form of energy to another. • Need to boost the signals • Need to mix the signal with others

  6. Audio Amplification/Processing • Amplifier – Definition: a device that boosts • Equalizer – a special frequency-dependent amplifier • Special Effects amplifier – Reverb,phasers, and time delay/speedup

  7. Audio Amplification/Processing • Mixing Consoles – “audio board” • Input signals, select signals, control signals, mix signals, combine signals, and route signals • Pots and sliding bars or faders produce a mix • Wave of the future is all computer (digital) mixing consoles and radio/TV stations.

  8. Video Amplification/Processing • Mixing Consoles – “The Switcher” • Buttons select camera that is on-line • Fader bars for audio and video • Special effects generators (usually digital) • Best known – “keying” on blue

  9. Video Amplification/Processing • Digital Video Effects (DVE) • Freeze-frame • Stretching or rotating a picture • Mirror image • Special shapes for pictures

  10. Video Amplification/Processing • Desktop Video • Use of PC to generate video • Camcorder/on-line to PC to storage • An Apple/Mac plus

  11. STEP 3: Signal Transmission • Got to get the signal from point “A’ to point “B” • By air • By wire • By cable • By Internet • By ???????

  12. Audio Transmission • Modulation actually does the work. • Carrier signal (fixed frequency BASE) • The audio signal is mixed in some way, either amplitude or frequency.

  13. Audio Transmission • Radio Frequencies • Medium Waves (MW) – 0.3 to 3MHz, AM radio is here • Very High Frequency (VHF) – 30 to 300MHz, 2-13 TV and FM are here • Ultra High Frequency (UHF) – 300 to 3GHz, 14-83 TV and microwave ovens are here

  14. Audio Transmission • Spectrum Management • How radio/TV service is administrated so there is not confusion and chaos • In the US: FCC is in control

  15. Audio Transmission • Radio Channels • 12000 radio stations in the US: 107 AM channels and 100 FM channels • Control of hours, power, antenna height and design is the control process • AM: 60 clear channels, 41 regional, 6 local • FM: In a zone – 80 commercial, 20 other

  16. Audio Transmission • Sidebands and Subcarriers • Sideband is above/below the carrier: stereo on FM • Subcarriers are a special signal in the stations frequency allocation: background music, stock reports, or utility load management on AM

  17. Video Transmission • Television Channels: • 1500 TV stations in the US. Each one uses 6MHz – equal to 30 FM and 600 AM stations • Video picture is 4MHz of AM signal • Audio in the picture is FM • Remainder is special guard bands to separate the signal information

  18. Video Transmission • TV Allocations: • VHF – 2 to 6 and 7 to 13 are in this band • UHF – 14 to 83 are in this band • The higher the channel, the higher the power needed to transmit to a coverage area. Channel 2 needs 100kwatts, 7 need 316kwatts, and 14 needs 5000kwatts. • The higher the wattage the higher the problems

  19. Video Transmission • High Definition TV • A real bag of worms • TV stations were given new “free” channel allocations and a deadline. • They were to meet the deadline and give their old channel allocations back to the FCC for reissue via auction. • But………

  20. Satellite Transmission • Satellite Terminology: • Geosynchronous orbits • C band – first satellites, 4 to 6 GHz • Ku band – latest, 12 to 14 GHz

  21. Satellite Transmission • Direct Broadcast Satellites (DBS) • High power • Smaller dish • Can be two way • 25% of market

  22. Satellite Transmission • Digital Audio Broadcasting (DAB) • Satellite to car • Just really being rolled out

  23. Wired Transmission (Again) • Cable Transmission • Coaxial cable • High, uniform power to receiver • Addressability • Pay-per-view • Fiber optic cable • 97% market penetration

  24. HOMEWORK ASSIGNMENT • Continue reading Chapter 3 • We will cover pages 68 to 74 on Friday

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