Multiplex communications – Fault recovery – Bypass an inoperative channel
Reexamination Certificate
1998-04-18
2001-10-09
Ngo, Ricky (Department: 2664)
Multiplex communications
Fault recovery
Bypass an inoperative channel
C370S228000, C370S323000, C370S325000, C333S101000, C455S012100
Reexamination Certificate
active
06301225
ABSTRACT:
BACKGROUND
The present invention relates generally to spacecraft communication apparatus, and more particularly, to amplifier redundancy ring communication apparatus that can be configured to use normally unused multiplexer channels when operating in high power mode.
The assignee of the present invention manufactures and deploys communication satellites that carry communication systems as their payloads. A typical communication system uses two or more separate and independent amplifier channels that each form a redundancy ring.
In an exemplary embodiment, a plurality of single input, multiple output, input multiplexers that are coupled to a multiple input, single output, output multiplexer by means of a set of amplifier channels that form the redundancy ring. Each redundancy ring contains a plurality of amplified communication paths (amplifier channels) that route signals from the outputs of the input multiplexers to the inputs of the output multiplexer.
Within each independent set of amplifier channels forming the redundancy ring, extra amplifier channels are provided that may be used in case of failure of one of the other amplifier channels within that redundancy ring. If an amplifier channel fails, one of the extra amplifier channels is switched into the circuit to replace it.
The amplified communication paths
20
a
each contain a traveling wave tube amplifier (TWTA), for example. Pairs of traveling wave tube amplifiers may be selectively coupled together to provide for high power operation. Thus, the traveling wave tube amplifiers may be controlled to operate in (1) a single traveling wave tube (TWT) mode and in (2) a high power combined traveling wave tube (TWT) mode using a coupled pair of traveling wave tube amplifiers. When the conventional system is configured to operate in the normal TWT mode, all of the outputs of the input multiplexers are routed to all of the inputs of the output multiplexer. Thus all communication channels are used. However, when the conventional system is configured to operate in the high power combined TWT mode, the communication path for the channel of the “coupled” amplifier is not used. Thus, all available communication channels of the conventional system are not used when it is operated in the high power mode.
The inability to use certain channels when operating in the high power mode is relatively inefficient. Furthermore, it would be desirable to have the option of using unused channels of a given output multiplexer when the high power combined TWT mode has been selected for another channel. It would therefore be desirable to have a communication system that permits the use of the normally unused output multiplexer channels when the system operates in a high power combined TWT mode.
Accordingly, it is an objective of the present invention to provide for communication apparatus that is selectively configurable to provide for the use of normally unused output multiplexer channels when it is operated in high power mode. It is a further objective of the present invention to provide for communication apparatus that uses selectively interconnected amplifier channels of its redundancy rings to permit normally unused output multiplexer channels to be used when the system is configured to operate in high power mode.
SUMMARY OF THE INVENTION
To accomplish the above and other objectives, the present invention provides for improved amplifier redundancy ring communication apparatus. The communication apparatus comprises a plurality of multiple output, input multiplexers and a plurality of multiple input, output multiplexers. Outputs of the input multiplexers are coupled to inputs of the output multiplexers by way of a plurality of amplifier channels. A plurality of redundant amplifier channels are provided that complete the redundancy ring. Each redundancy ring contains a plurality of amplified communication paths (amplifier channels) that route signals from the outputs of the input multiplexers to the inputs of the output multiplexer along with additional amplifier channels that may be used in case of failure of one of the amplifier channels.
As was the case with the conventional communication apparatus discussed in the Background section, pairs of amplifier channels may be selectively coupled together. In particular, the amplifier channels may be configured to operate in a single amplifier mode wherein each amplifier channel operates independently, and in a high power combined amplifier mode wherein both amplifier channels of a pair are coupled together to provide high power output.
The improvement provided by the present invention is that switching circuitry is provided that (1) permit the extra amplifier channels to be switched into the circuit if other amplifier channels fail, as is the case with the prior system, but (2) also provides the capability to switch an unused amplifier channel into the circuit to provide a communication channel between the corresponding output and input of the input and output multiplexers that is normally provided by the “coupled” amplifier channel. The unused amplifier channel that is switched into the circuit is typically the corresponding amplifier channel of the other redundancy ring. However, this need not be the case, in that any of the unused amplifier channels may be switched into the circuit to provide the communication path.
The present invention thus provides the capability to use previously unused multiplexer channels by switching in a single amplifier or combined pair of traveling wave tube amplifiers from a different TWT redundancy ring. The aspect of the present invention provides added flexibility for customers and a simplicity in the design that “backfills” the unused multiplexer channels.
To implement the present invention, outputs of the input multiplexers of each redundancy ring are interconnected together by means of controllable switches. Similarly, inputs of the output multiplexers of each redundancy ring are interconnected together by means of controllable switches. The switches are controlled by means of a controller that selectively activates the switches to interconnect a particular input multiplexer output to the appropriate output multiplexer input, thus providing a communication path therebetween. The arrangement of switches permits controlled selection of the alternative path through any of the unused amplifier channels.
REFERENCES:
patent: 5862462 (1999-01-01), Tyner et al.
patent: 5978652 (1999-11-01), Burr et al.
patent: 6020796 (2000-02-01), Collar et al.
Ngo Ricky
Space Systems Loral, Inc.
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