Transmission apparatus for orbiting satellite
First Claim
1. A transmission apparatus for an orbiting satellite which travels around the earth along a low or intermediate orbit, comprising:
- M input terminals, M being an integral number equal to or grater than 2;
a frame generator for generating a frame synchronizing signal at a fixed interval;
M composers for forming frame signals from respective transmission data received at said M input terminals in response to the frame synchronizing signal from said frame generator;
M transmitters for receiving outputs of said M composers and outputting M spot beams having different radiation directions from one another;
M frame signal delay circuits individually interposed between said M composers and said M transmitters; and
delay time setting means for setting, for each of said M frame signal delay circuits, a delay time which varies inversely proportionally to the distance from the orbiting satellite to the center of a cell resulting from a corresponding spot beam transmitted to the earth.
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Abstract
A transmission apparatus for an orbiting satellite which can establish stabilized frame synchronization even if the distance between the round-trip satellite and a communications terminal varies and which can minimize the displacement between a frame signal received on the ground and another frame signal generated in a communications terminal. The transmission apparatus comprises M (M is an integral number equal to or greater than 2) composers for forming frame signals, M transmitters for outputting M spot beams having different radiation directions, and M delay circuits interposed between the composers and the transmitters. The delay times of the delay circuits are set so that they are long where the radiation angles of the corresponding spot beams are small, but they are shorter where the radiation angles are larger.
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Citations
16 Claims
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1. A transmission apparatus for an orbiting satellite which travels around the earth along a low or intermediate orbit, comprising:
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M input terminals, M being an integral number equal to or grater than 2; a frame generator for generating a frame synchronizing signal at a fixed interval; M composers for forming frame signals from respective transmission data received at said M input terminals in response to the frame synchronizing signal from said frame generator; M transmitters for receiving outputs of said M composers and outputting M spot beams having different radiation directions from one another; M frame signal delay circuits individually interposed between said M composers and said M transmitters; and delay time setting means for setting, for each of said M frame signal delay circuits, a delay time which varies inversely proportionally to the distance from the orbiting satellite to the center of a cell resulting from a corresponding spot beam transmitted to the earth. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transmission apparatus for an orbiting satellite, comprising:
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input terminals for receiving transmission data; a frame generator which generates a frame synchronizing signal at a fixed interval; composers receiving transmission data from said input terminals and outputting frame signals in response to the frame synchronizing signal for said frame generator; frame signal delay circuits which receive the frame signal outputs of the composers and interpose a delay time to each such frame signal output; transmitters processing the delayed frame signal outputs of said frame signal delay circuits and transmitting to earth spot beams having different radiation directions, wherein the spot beams result in communication cells on earth; and the delay time interposed on each output signal of said frame signal delay circuits varies inversely proportionally to the distance from the orbiting satellite to the center of a communication cell on earth. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A transmission apparatus for an orbiting satellite, comprising:
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input terminals for receiving transmission data; a frame generator which generates a frame synchronizing signal at a fixed interval; composers receiving transmission data from said input terminals and outputting frame signals in response to the frame synchronizing signal for said frame generator; frame signal delay circuits which receive the frame signal outputs of the composers and interposes a delay time to each such frame signal output; transmitters processing the delayed frame signal outputs of said frame signal delay circuits and transmitting to earth spot beams having different radiation directions, wherein the spot beams result in communication cells on earth; and the delay time interposed on each output signal of said frame signal delay circuits increases as the radiation angle of the spot beams increases, thus the delay time varies inversely proportionally to the distance from the orbiting satellite to the center of a communication cell on earth.
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Specification