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MDIA 308

MDIA 308. Television. Television. Like film – television is actually a series of still images presented to the eye in rapid succession Earliest experiments in 1890s Italian monk – Casselli Pictures by wire. Television. Mechanical Television Paul Nipkow – scanning disk Nipkow disk

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MDIA 308

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  1. MDIA 308 Television

  2. Television • Like film – television is actually a series of still images presented to the eye in rapid succession • Earliest experiments in 1890s • Italian monk – Casselli • Pictures by wire

  3. Television • Mechanical Television • Paul Nipkow – scanning disk • Nipkow disk • John Loge Baird • Scottish inventor working with BBC • Launched the first system based on mechanical scanning

  4. Nipkow disk

  5. Television • Electronic television – cathode ray tube • Vladimir Zworykin • Iconoscope • Philo T. Farnsworth • Image Dissector

  6. Television

  7. Electronic scanning

  8. White light Beam splitter

  9. White light Cathode ray tube Beam splitter

  10. Color TV screens

  11. Television standards • National Television Standard Commission (NTSC) • Standard Definition (SDTV) • 4:3 aspect ratio • 525 lines of horizontal resolution • 30 frames per second • 60 fields per second • 2 fields per frame • Interlace scanning

  12. Television standards • High definition (HDTV) • 16:9 aspect ratio • 1080 lines of horizontal resolution • 30 frames per second • Progressive scanning

  13. Magnetic tape recording • Magnetic recording heads are transducers that convert electrical energy into magnetic • Recording heads are electromagnets • Audio current creates an alternating magnetic field • The magnetic field is focused at the “gap” in the record head

  14. Magnetic tape recording

  15. Magnetic tape recording • The fluctuations in the magnetic field are stored on tape by re-arranging the magnetic polarity of the “metal” surface of the tape • The tape surface is made from powdered metals, like FeO2, or iron oxide (rust) • The metals are attached to a plastic backing with binder (glue)

  16. Magnetic tape recording • Playback heads are constructed in a nearly identical manner • During playback, a current is induced to flow in the coil of the head by the magnetic charges of the tape surface

  17. Analog tape recording Reel to reel Fundamentals of Audio Production. Chapter 6.

  18. Videotape • Ampex corporation invented the videotape recorder • Allowed television programs to be recorded and “mistakes” could be corrected

  19. Quadruplex Videotape

  20. Quadruplex

  21. Helical scan

  22. Helical scan

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