MI 101 Lecture Notes - Lecture 9: Coaxial Cable, Halftone, Optical Fiber
Document Summary
Photography: discovery that light causes silver halide to turn dark. Divided photo into micro grid (like pixels) Each tiny square had raised dot (size registered tone of gray) Essential technology remained mechanical until 1970s (digital) Telegraph: not really a mass medium (p. 33) Telephone: sound waves converted to electrical signals. From light bulbs to vacuum tubes: amplifiers for ld telephone tuners for radio receivers. Convergence : telephone & radio tech -sound for movies. Farnsworth invented an all-electronic version (14 years old) Digital tv electronic pick-up tube of analog tv became a light-sensitive charge- Hdtv standard (u. s. ) analog picture resolution of 480 lines, aspect ratio of 4:3 & fm sound -to 1080 lines & 16:9 & 5. 1. Coaxial cable -bandwidth (video, multiple voice channels) Network tv to interconnect affiliated stations. Cable tv to bring multiple channels from community antenna to subscribing households. Multiple transponders (receive signals from earth stations; shift frequencies & amplify; transmit back to earth stations)
