COMM 330 Lecture Notes - Lecture 16: Frequency, Radio Spectrum, Sine Wave
29 Mar 2017
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Document Summary
How radio tech changes impact the radio industry. New technologies impact on ownership patterns and control. 1905 fessenden invents continuous wave voice transmitter. 1906 de forest patents audio/vacuum tube - enables sound, voice and music. Amplitude modulation (am), 535 to 1705 khz. Frequency modulation (fm), 88 to 108 mhz. Hidden between am & fm signals, 3mhz to 30mhz. 1920s us navy returned radio to civilian hands. First coast to coast transmission - 1915. Split into red" (entertainment: and blue" (info) networks. News programming makes radio new home appliance. Allowed single owner to own more stations. Radio wavelengths - distance between wave peak and the next. Frequency- number of waves arriving each second. Radio transmitter create a rapid electric current. Run through a wire creates a radio transmitter. Transmitter sends program signals as fragments broken into coded digits. Fragments sent many times to increase chances of it getting through. Receiver piece together fragments into uninterrupted program signal.
