Mixed analog-digital service distribution system and method
First Claim
1. A digital-analog mixed service distribution system, comprising:
- a service signal storage unit including;
a first storage that stores a plurality of digital service signal,a first modulator that modulates a specified digital service signal onto a first modulated signal and converts the first modulated signal into a first analog service signal;
a second storage that stores at least one second analog service signals for multicast service; and
a first mixer that mixes at least one of the second analog service signals with the first analog service signal to generate a first mixed signal;
a path coupled to said service signal storage unit and including a digital transmission channel that transmits at least one digital service signal, and an analog transmission channel that transmits the first mixed signal; and
a subscriber terminal coupled to said service signal storage unit by said path and receiving the first mixed signal and a digital service signal transmitted thereby, said subscriber terminal includinga second modulator that modulates the received digital service signal onto a second modulated signal and converts the second modulated signal into a third analog service signal anda second mixer that mixes the third analog service signal with the first mixed signal to generate a second mixed signal.
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Accused Products
Abstract
By transmitting an analog CATV signal output from a CATV-HE (CAble TeleVision-Head End) to an HDT (Host Digital Terminal), an analog transmission channel for transmitting the analog CATV signal to an ONU (Optical Network Unit) is included in a path housing a digital transmission channel for transmitting a digital service signal for individual distribution service to the ONU. Furthermore, a digital service signal for multicast service is modulated and converted into an analog service signal by a modulator in the HDT. Then, the converted signal is mixed with the analog CATV signal, and transmitted to the ONU. Accordingly, each of the ONUs is equipped with only a built-in modulator for modulating the digital service signal for individual distribution service.
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Citations
11 Claims
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1. A digital-analog mixed service distribution system, comprising:
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a service signal storage unit including; a first storage that stores a plurality of digital service signal, a first modulator that modulates a specified digital service signal onto a first modulated signal and converts the first modulated signal into a first analog service signal; a second storage that stores at least one second analog service signals for multicast service; and a first mixer that mixes at least one of the second analog service signals with the first analog service signal to generate a first mixed signal; a path coupled to said service signal storage unit and including a digital transmission channel that transmits at least one digital service signal, and an analog transmission channel that transmits the first mixed signal; and a subscriber terminal coupled to said service signal storage unit by said path and receiving the first mixed signal and a digital service signal transmitted thereby, said subscriber terminal including a second modulator that modulates the received digital service signal onto a second modulated signal and converts the second modulated signal into a third analog service signal and a second mixer that mixes the third analog service signal with the first mixed signal to generate a second mixed signal. - View Dependent Claims (2, 3, 4, 5)
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6. A method for digital-analog mixed service distribution, comprising the steps of:
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storing a plurality of digital service signals, including a specified digital service signal for multicast service; modulating the specified digital service signal onto a first modulated signal; converting the first modulated signal into a first analog service signal; storing at least one second analog service signal; mixing the first analog service signal with the at least one second analog service signal to generate a first mixed signal; modulating at least one of the transmitted digital service signals onto as second modulated signal; converting the second modulated signal into a third analog service signal; and mixing the third analog service signal with the first mixed signal to generate a second mixed signal. - View Dependent Claims (7, 8, 9, 10)
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11. A computer-readable medium encoded with a program for digital-analog mixed service distribution, said program comprising the functions of:
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storing one or more digital service signals, including a specified digital service signal for multicast service; modulating the specified digital service signal onto a first modulated signal; converting the first modulated signal into a first analog service signal; storing one or more second analog service signals; mixing the first analog service signal with at least one of the second analog service signals to generate a first mixed signal; transmitting a first selected signal of the at least one digital service signal and a second selected signal of the at least one first analog signal, the first and second selected signals being transmitted through the same path; modulating at least one of the transmitted digital service signals onto a second modulated signal; converting the second modulated signal into a third analog service signal; and mixing the third analog service signal with the first mixed signal to generate a second mixed signal.
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Specification