Never before have I witnessed compressed into a

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 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

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

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

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

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

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

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

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

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