Television captioning system
First Claim
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1. A television system for transmitting and receiving coded data which can be received by a viewer and displayed on the receiving television receiver as readable alphanumerics, comprising:
- a television transmitting system including a source of vertical and horizontal synchronization signals and an FM audio transmitter;
a data source;
means for generating a first ultrasonic subcarrier;
first means for modulating said first ultrasonic subcarrier with the output from said data source;
means for generating a second ultrasonic subcarrier;
second means for modulating said second ultrasonic subcarrier with one of said synchronization signals;
means for summing the outputs from said first and second modulating means;
means for applying the output of said summing means to the FM audio transmitter;
a television receiver for receiving said modulated first and second subcarriers;
means coupled to said television receiver for receiving said modulated first and second subcarriers from said television receiver;
means coupled to said receiving means for demodulating said first and second subcarriers; and
means coupled to said demodulating means for converting the coded data to alphanumerics displayed on the screen of the television receiver.
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Abstract
Captioning of television presentations is achieved by transmitting digital data superimposed on the normal FM sound signal by modulation of an ultrasonic subcarrier and receiving the digital data at a viewer'"'"'s television receiver by picking up the ultrasonic signal from the television receiver'"'"'s loudspeaker; the received digital data being demodulated and applied to the television receiver as readable alphanumeric captions.
141 Citations
16 Claims
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1. A television system for transmitting and receiving coded data which can be received by a viewer and displayed on the receiving television receiver as readable alphanumerics, comprising:
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a television transmitting system including a source of vertical and horizontal synchronization signals and an FM audio transmitter; a data source; means for generating a first ultrasonic subcarrier; first means for modulating said first ultrasonic subcarrier with the output from said data source; means for generating a second ultrasonic subcarrier; second means for modulating said second ultrasonic subcarrier with one of said synchronization signals; means for summing the outputs from said first and second modulating means; means for applying the output of said summing means to the FM audio transmitter; a television receiver for receiving said modulated first and second subcarriers; means coupled to said television receiver for receiving said modulated first and second subcarriers from said television receiver; means coupled to said receiving means for demodulating said first and second subcarriers; and means coupled to said demodulating means for converting the coded data to alphanumerics displayed on the screen of the television receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for receiving data via a television receiver loudspeaker which was transmitted by means of a modulated ultrasonic subcarrier superimposed on the television FM sound signal, comprising:
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means proximate the television receiver loud speaker responsive to the flux field about the loudspeaker'"'"'s voice coil; and means coupled to said means responsive for demodulating the output thereof. - View Dependent Claims (13, 14)
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15. Television transmitting apparatus, including means for generating vertical and horizontal synchronization signals, for transmitting a first distinct signal and a second distinct signal, including the television vertical synchronization signals, along with the normal audio information, comprising:
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a first ultrasonic subcarrier oscillator; means for modulating the output of said first oscillator with the first distinct signal; a second ultrasonic subcarrier oscillator;
said second oscillator being phase locked to the horizontal synchronization signals;means for modulating the output of said second oscillator with said vertical synchronization signals; and means for combining the outputs from said modulating means with the normal audio information. - View Dependent Claims (16)
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Specification