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US 8,942,742 B2Granted
Method and apparatus for synchronizing multiple transmitters
AssigneeFox Digital Enterprises, Inc.
InventorRobert E. Wetmore
Life of this patent
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Abstract
A method and apparatus for synchronizing multiple transmitters is disclosed. A global time reference is used to synchronize the arrival of data from a plurality of secondary transmitters in a receiver station. In one embodiment, the global time reference is provided by a GPS satellite, and may also be used to synchronize the carriers of the signals received at the receiver station from each of the plurality of transmitters. In one embodiment, a pilot signal used for ATSC applications is added by the secondary transmitters.
Claims22
A method of transmitting a media program information, comprising the steps of:
- receiving a channel coded data comprising the media program information;
- generating a first signal having the channel coded data and periodic synchronization information, the first signal for transmitting the media program information for reception by a remote receiver station disposed in a coverage area of a first secondary transmitter and a second secondary transmitter;
- transmitting the first signal from a master transmitter;
- receiving the first signal in the first secondary transmitter;
- receiving the first signal in the second secondary transmitter;
- transmitting a first retransmitted signal having the media program information from the first secondary transmitter;
- and
- transmitting a second retransmitted signal having the media program information from the second secondary transmitter;
- wherein the first retransmitted signal is temporally offset from the second retransmitted signal by an amount determined at least in part according to the periodic synchronization information and a common time reference;
- and
- wherein the periodic synchronization information comprises a plurality of data fields and the step of generating the first signal comprises the steps of:
- (a) receiving a first data field, the first data field comprising a first symbol transmitting no information between the master transmitter and the first and second secondary transmitters;
- (b) receiving a first periodic timing signal generated from the common time reference;
- (c) substituting a counter symbol for the first symbol to generate a modified first data field;
- (d) incrementing the counter symbol;
- and
- (e) receiving a second data field, the second data field comprising the first symbol transmitting no information between the master transmitter and the first and second secondary transmitters;
- (f) substituting the incremented counter symbol for the symbol to generate a modified second data field;
- and
- (g) temporally aligning the first data field with the first periodic time signal;
- (h) generating the first signal from the modified and aligned first data field and the second data field and the channel coded data.
18 more elements
An apparatus for transmitting media program information, comprising:
- a master transmitter for receiving a channel coded data comprising the media program information and for generating a first signal having the channel coded data and periodic synchronization information;
- a first secondary transmitter, for receiving the first signal and for transmitting a first retransmitted signal having the media program information from the first secondary transmitter;
- a second secondary transmitter, for receiving the first signal and for transmitting a second retransmitted signal having the media program information from the second secondary transmitter;
- wherein the first retransmitted signal is temporally offset from the second retransmitted signal by an amount determined at least in part according to the periodic synchronization information and a common time reference;
- and
- wherein the periodic synchronization information comprises a plurality of data fields and the master transmitter comprises:
- means for receiving a first data field, the first data field comprising a first symbol transmitting no information between the master transmitter and the first and second secondary transmitters;
- means for receiving a first periodic timing signal generated from the common time reference;
- means for substituting a counter symbol for the first symbol to generate a modified first data field;
- means for incrementing the counter symbol;
- means for receiving a second data field, the second data field comprising the first symbol transmitting no information between the master transmitter and the first and second secondary transmitters;
- means for substituting the incremented counter symbol for the symbol to generate a modified second data field;
- means for temporally aligning the first data field with the first periodic time signal;
- and
- means for generating the first signal from the modified and aligned first data field and the second data field.
12 more elements
Dependencies are inferred from the claim text.