Digital simulcast transmission system
First Claim
1. A simulcast broadcast system comprising:
- a hub including;
a clock for maintaining a system time;
an interface unit for receiving signals to be broadcast and connected to said clock for receiving said system time, said interface unit functioning to;
determine the rate at which the signals are to be broadcast;
packetize the signals into a plurality of signal blocks wherein signals in said signal blocks are in a digital format; and
provide each said signal block with a start time based on said system time and a rate signal representing a desired broadcast rate liar the signals;
a linking unit connected to said interface unit for receiving said signal block and for forwarding said signal block over a link channel; and
a plurality of stations, each said station including;
a transmitter for broadcasting said signals to be broadcast;
a linking unit connected to the link channel for receiving said signal blocks;
a clock for maintaining said system time; and
a station processor that is connected to said station clock for receiving said system time, that is connected to said linking unit for receiving said signal blocks, and that is connected to said transmitter for forwarding the signals to be simulcast thereto, said station processor functioning to forward said signals to be broadcast in each said signal block to said transmitter when said system time equals said start time in said signal block to be broadcast at a rate based on said rate signal in said signal block.
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Accused Products
Abstract
A simulcast system for broadcasting the same signal for a number of spaced-apart broadcast sites is disclosed. The system (20) of this invention includes a hub (28) adapted to receive the signal to be simulcast and a number of stations (30) that actually broadcast the signal. The hub places the digital signal packets referred to as PDBs (36). As part of the signal packetization process, the hub evaluates the rate at which the signals should be broadcast and assigns a start time at which the signals should be broadcast; this information is attached to the PDBs. After a PDB is created it is forwarded to the stations over a link channel. Each station includes a station controller (32) and a station transmitter (34). The station controller, upon receiving a PDB, forwards the signal therein to the transmitter at the start time indicated and at the appropriate broadcast rate. All of the stations transmitting the signals contained within a single PDB do so based on the start time and broadcast rate information contained in that PDB. Consequently, each station broadcasts the same signals at the same time and at the same rate so as to ensure their simultaneous transmission.
34 Citations
47 Claims
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1. A simulcast broadcast system comprising:
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a hub including; a clock for maintaining a system time; an interface unit for receiving signals to be broadcast and connected to said clock for receiving said system time, said interface unit functioning to;
determine the rate at which the signals are to be broadcast;
packetize the signals into a plurality of signal blocks wherein signals in said signal blocks are in a digital format; and
provide each said signal block with a start time based on said system time and a rate signal representing a desired broadcast rate liar the signals;a linking unit connected to said interface unit for receiving said signal block and for forwarding said signal block over a link channel; and a plurality of stations, each said station including; a transmitter for broadcasting said signals to be broadcast; a linking unit connected to the link channel for receiving said signal blocks; a clock for maintaining said system time; and a station processor that is connected to said station clock for receiving said system time, that is connected to said linking unit for receiving said signal blocks, and that is connected to said transmitter for forwarding the signals to be simulcast thereto, said station processor functioning to forward said signals to be broadcast in each said signal block to said transmitter when said system time equals said start time in said signal block to be broadcast at a rate based on said rate signal in said signal block. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A paging system for simulcasting pages, said paging system configured for connection to a publicly switched telephone network, said paging system comprising:
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a paging terminal connected to the publicly switched telephone network for receiving calls for system subscribers, said paging terminal functioning to generate pages in response to calls for system subscribers; a hub including; a clock for maintaining a system time; an interface unit connected to said paging terminals for receiving said pages and connected to said clock for receiving said system time, said interface unit functioning to;
determine the rate at which said pages are to be broadcast;
packetize the signals into a plurality of paging data blocks wherein said pages in said paging data blocks are in a digital format; and
provide each said paging data block with a start time based on said system time and a rate signal representing a desired broadcast rate for the pages;a central processing unit connected to said interface unit for receiving said paging data blocks, said central processing unit functioning to place said paging data blocks in station packets; a linking unit connected to said central processing unit for receiving said station packets and for forwarding said station packets over a link channel; and a plurality of stations, each said station including; a transmitter for broadcasting said pages to be broadcast; a linking unit connected to the link channel for receiving said station packets; a clock for maintaining said system time; and a station processor that is connected to said station clock for receiving said system time, that is connected to said linking unit for receiving said stations packets, and that is connected to said transmitter for forwarding said pages to be simulcast thereto, said station processor functioning to remove said paging data blocks from said packets in which said paging data blocks are contained and forward said pages to be broadcast in each said paging data block to said transmitter when said system time equals said start time in said paging data block to be broadcast at a rate based on said rate signal in said paging data block. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. A method of distributing paging signals generated by a paging terminal for broadcast by stations distal from the hub, the paging signals having a selected transmission rate, including the steps of:
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forwarding the paging signals to a hub; determining a system time at which each of the paging signals arrives at said hub by reference to a clock at the hub that maintains said system time; determining the transmission rate of the paging signals generated by the paging terminal; storing said paging signals in a digital format in a buffer at said hub; when a selected number of paging signals are stored in said buffer at said hub, placing said selected number of paging signals in a paging data block, and providing said paging data block with a start time, said start time based on said system time of reception of the first paging signal in said paging data block, and a rate signal based on the transmission rate of the paging signals; and forwarding said paging data block to the stations. - View Dependent Claims (31, 32, 33)
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34. A hub unit for a paging system having a paging terminal from which pages are generated, a number of spaced-apart stations from which pages are broadcast, and a number of link channels over which signals are forwarded to the stations, said hub comprising:
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a clock for maintaining a system time; an interface unit connected to the paging terminal for receiving the pages and connected to said clock for receiving said system time, said interface unit functioning to;
determine the rate at which the pages are to be broadcast;
packetize the pages into a plurality of paging data blocks wherein the pages in said paging data blocks are in a digital format; and
provide each said paging data block with a start time based on said system time and a rate signal based on the rate the pages should be broadcast;a linking unit connected to the link channels and connected to said interface unit for receiving said paging data blocks from said interface unit and for selectively forwarding said paging data blocks over link channels to the stations; a central processing unit connected to said interface unit for monitoring the generation of said paging data blocks and connected to said link unit for establishing over which link channel a particular paging data block is forwarded to the stations. - View Dependent Claims (35, 36, 37, 38, 39)
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40. A station for a paging system for broadcasting pages contained in paging data blocks, each said paging data block includes a start time signal and a broadcast rate signal, and wherein the paging data blocks are forwarded over a link channel, said station including:
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a transmitter for broadcasting the pages; a linking unit connected to the link channel for receiving the paging data blocks; a clock for maintaining a system time; and a station processor that is connected to said station clock for receiving said system time, to said linking unit for receiving said paging data blocks, and to said transmitter for forwarding the signals to be simulcast thereto, said station processor functioning to remove the pages from the paging data blocks and forward the pages to said transmitter for broadcast when said system time equals said start time in the paging data block to be broadcast at a rate based on the broadcast rate in the paging data block. - View Dependent Claims (41, 42)
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43. A paging system for simulcasting pages, comprising:
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a paging terminal for receiving calls for system subscribers and functioning to generate corresponding pages;
a system controller including;(a) a clock for maintaining a system time; (b) means for receiving said pages and for receiving said system time, said means packetizing said pages into a plurality of paging data blocks, wherein said paging data blocks are in a digital format, and further functioning to provide each paging data block with a start time based on said system time and a rate signal representing a desired broadcast rate for the pages; and (c) a first linking unit for forwarding said paging data blocks over a link channel; and a plurality of paging stations, each paging station including; (a) a transmitter for broadcasting said pages; (b) a second linking unit for receiving said paging data blocks from the link channel; (c) a station clock for maintaining a station time having a predetermined relationship to said system time; and (d) a station controller for receiving said station time from said station clock and for receiving said paging data blocks from said second linking unit, and for forwarding said pages to be simulcast to said transmitter, said station controller removing said pages from said paging data blocks and forwarding said pages to said transmitter, once said station time equals said start time in said paging data block to be broadcast, at a rate based on said rate signal in said paging data block. - View Dependent Claims (44, 45)
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46. A method of simulcasting pages generated by a paging terminal from a plurality of paging stations, each of said paging stations having a transmitter over which the pages are broadcast and a clock, said method comprising the steps of:
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packetizing the pages in a plurality of paging data blocks, and providing each of said paging data blocks with a message indicative of a broadcast start time and a rate signal representing a desired broadcast rate for the pages; transmitting said paging data blocks to the paging stations, wherein each of said paging data blocks is sent to at least two paging stations; maintaining the clocks at each of said paging stations so that the clocks all indicate a station time having a predetermined relationship to a system time; and upon receipt of one of said paging data blocks at a paging station, removing the pages in said paging data block therefrom, reading said broadcast time, and then forwarding the pages to the transmitter for broadcast when said station time equals said start time in said paging data block. - View Dependent Claims (47)
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Specification