Multiple audio and video signal providing apparatus
First Claim
1. A signal providing apparatus comprising:
- analog video signal providing means for providing an RF-modulated analog video signal having a bandwidth;
at least one digital video signal providing means providing an RF-modulated digital video signal having a bandwidth comprising;
time-division multiplexing means for multiplexing a plurality of compressed digital video signals by time division, andRF-modulating means for modulating a carrier signal with an output signal from the time-division multiplexing means, wherein a bandwidth of the carrier signal used by said RF-modulating means is equal to the bandwidth of the RF-modulated analog video signal; and
frequency-division multiplexing means for multiplexing by frequency-division the RF-modulated analog video signal from the analog video signal providing means and the RF-modulated digital video signal or signals from the at least one digital video signal providing means.
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Abstract
A video signal provider multiplexes digital video signals for four channels and provides a signal the bandwidth of which is limited to 6 MHz by RF-modulation. An analog video signal provider provides another signal the bandwidth of which is limited to 6 MHz by RF-modulation. A digital audio signal provider multiplexes digital audio signals for 32 channels and provides another signal the bandwidth of which is limited to 6 MHz by RF-modulation. Such signals are combined and transmitted through a coaxial cable 14 to a controller. In this example, such signal providing apparatus can provide a maximum of 84 channels (=126 MHz (the bandwidth for video signal of the coaxial cable)/6 MHz×4 ch), which number is significantly larger than the 20 channels provided in the prior art.
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Citations
16 Claims
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1. A signal providing apparatus comprising:
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analog video signal providing means for providing an RF-modulated analog video signal having a bandwidth; at least one digital video signal providing means providing an RF-modulated digital video signal having a bandwidth comprising; time-division multiplexing means for multiplexing a plurality of compressed digital video signals by time division, and RF-modulating means for modulating a carrier signal with an output signal from the time-division multiplexing means, wherein a bandwidth of the carrier signal used by said RF-modulating means is equal to the bandwidth of the RF-modulated analog video signal; and frequency-division multiplexing means for multiplexing by frequency-division the RF-modulated analog video signal from the analog video signal providing means and the RF-modulated digital video signal or signals from the at least one digital video signal providing means. - View Dependent Claims (2, 3, 4, 5)
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6. A method for providing signals comprising the steps of:
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providing an RF-modulated analog video signal having a bandwidth; providing at least one RF-modulated digital video signal having a bandwidth comprising the steps of; time-division multiplexing a plurality of compressed digital video signals by time division, and RF-modulating a carrier signal with an output signal from the time-division multiplexing step, wherein a bandwidth of the carrier signal used in said RF-modulation is equal to the bandwidth of the RF-modulated analog video signal; and frequency-division multiplexing by frequency-division the RF-modulated analog video signal and the RF-modulated digital video signal or signals. - View Dependent Claims (7, 8, 9, 10)
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11. A signal providing system comprising:
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analog video signal providing means for providing an RF-modulated analog video signal having a bandwidth; at least one digital video signal providing means for providing an RF-modulated digital video signal having a bandwidth comprising; video time-division multiplexing means for multiplexing a plurality of compressed digital video signals by time division, and RF-modulating means for modulating a carrier signal with an output signal from the time-division multiplexing means, wherein a bandwidth of the carrier signal used by said RF-modulating means is equal to the bandwidth of the RF-modulated analog video signal; frequency-division multiplexing means for multiplexing by frequency-division the RF-modulated analog video signal from the analog video signal providing means and the RF-modulated digital video signal or signals from the at least one digital video signal providing means; video tuner means for receiving and demodulating a signal output by said frequency-division multiplexing means and for selecting a signal having a specific frequency; video selecting means for selecting from a signal output by said video tuner means one of said compressed digital video signals multiplexed by said video time-division multiplexing means or said analog video signal; video expanding means for expanding said signal selected by said video selecting means; and display means for receiving and displaying a signal expanded by said video expanding means. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification