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Never before have I witnessed compressed into a single device so much ingenuity, so much brain power, so much developme

Never before have I witnessed compressed into a single device so much ingenuity, so much brain power, so much development, and such phenomenal results David Sarnoff. Background Technologies. Telephony Morse - telegraph Bell - telephone Radio Hertz - generate electromagnetic waves

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Never before have I witnessed compressed into a single device so much ingenuity, so much brain power, so much developme

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  1. Never before have I witnessed compressed into a • single device so much ingenuity, so much brain • power, so much development, and such • phenomenal results • David Sarnoff

  2. Background Technologies • Telephony • Morse - telegraph • Bell - telephone • Radio • Hertz - generate electromagnetic waves • Marconi - electromagnetic waves and antennas • Armstrong - FM modulation • Vacumn tubes and Amplifiers • Geissler - first vacumn tube • Fleming - vacumn tube diode • Deforest - triode and feedback amplifier • Photoelectric • Phosphoresence, Selenium photoconductive (Ball, Smith) • “kathode” ray tube

  3. Mechanical Television • First television systems • LeBlanc (1880) raster scanning • John Baird’s Nipkow disk system • C. Francis Jenkin’s prismatic ring system • Ernst Alexanderson’s mirror drum system • Big problems • 1. Mechanical limitations • Large, fast spinning disks • Holes limited light, resolution (14 scanlines) • 2. Detectors • Slow: temporal blur • Insensitive: bright lights, amplifier • Deployed in Great Britain, US, …

  4. Clever Enhancements • Color • Separate holes in Nipkow • Field sequential • Night • Infrared television • Stereo • Binocular Nipkow disks • Many, many, many mechanical designs • Quote on p. 84

  5. All-Electronic Television • 1908 2 synchronized cathode ray tubes (Swinton) • Philo Farnsworth – solo inventor • First demonstration in 1927 in San Francisco • Receiver: Oscillite • Camera: Image Dissector • Vladimir Zworykin – RCA industrial research • Receiver: Kinescope (1929) • Camera: Iconoscope (1931), Orthicon (1933) • World’s Fair demonstration – 343 lines, 60 fields • NTSC 1941, deployment delayed > WWII

  6. Electronic Camera • The key to television was the camera • Key ideas • Photoelectric plate becomes positively charged when exposed to light • Scan the plate with an electron beam, electrons attracted to positive atoms and increases beam current • Major breakthroughs • Electrostatic deflection, deflect before accelerate • Store charge • Low-voltage scan, same-side scan • Amplifier - multipactor • Sawtooth scanning pattern

  7. Color Television • CBS proposed field-sequential color system using a spinning wheel • RCA/NBC system • Color camera - 3 bw cameras w/ dichroic mirrors • Color receiver - 3 beams, phosphors, shadow mask • Signal compatible w/ bw • YC perceptual encoding (C less bandwidth) • Color subcarrier

  8. Background to HDTV • Situation 1987 • Land-Mobile wanted unused broadcast spectrum; FCC decides in their favor • Broadcasters invent HDTV scenario • NHK demonstration of analog HDTV • Analog 1192:60 • Satellite broadcast • Used 2 channels (8 Mhz) • Reaction • Can’t cede the technology the Japanese • Can’t go with an analog standard

  9. ATSC • FCC Advanced Television Standards Committee • Key competitors: • Zenith and Bell Labs: 8-VSB and progressive • General Instruments and MIT: digital (mpeg) • Philips, Sarnoff (RCA), Thomson • 1993 Grand Alliance formed • 1996 Telecommunications Act • Simulcast: digital and analogy • Loan 2nd channel through 2004(?) • Experiment w/ different video/data formats

  10. Broadcasters vs. Computers • War between computer companies/broadcasters • Major issues: • Square pixels • Interlaced vs. progressive • Resolution and formats • Flexible multimedia formats • Datacasting • Deployment rate • Convergence • Analog to digital a bigger transition than • Mechanical to eletronic!

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