Multiport Amplifier Emulation for Satellite Cross-Talk Isolation
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Solution Overview
Problem
Multiport amplifiers in satellite communication systems face challenges in maintaining isolation between signals, leading to cross-talk issues due to the complexity and resource-intensive hardware requirements for tracking and compensation.
Innovation Solution
A method and apparatus that utilize gain and phase adjusting means within the multiport amplifier, combined with a multiport amplifier emulation means, to assess and adjust cross-talk components using real communication signals or pilot tones, reducing the need for onboard processing and hardware by employing a digital signal processor or ground station-based signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If feedback loops with null detection are used to maintain isolation in multiport amplifiers, then signal isolation is improved, but onboard hardware complexity and processing requirements increase significantly
Solution Approach 1:
The patent creates a digital copy of the multiport amplifier's transfer function in the form of a complex gain matrix. This mathematical model replicates the amplifier's signal routing and isolation characteristics, allowing cross-talk assessment to be performed through digital signal processing rather than physical feedback hardware. The complex gain matrix serves as a virtual replica that enables isolation measurement without requiring additional onboard hardware.
Solution Approach 2:
The patent replaces the mechanical/physical feedback loop system with a digital signal processing approach. Instead of using physical null detection hardware and feedback amplifiers onboard the satellite, the system uses digital correlation processing between input and output signals to assess cross-talk. This substitution dramatically reduces hardware complexity while maintaining the ability to measure and maintain signal isolation.
2Power
If multiple amplifier units are used in parallel to increase output power, then power availability is improved, but cross-talk between output ports increases
Solution Approach 1:
The patent implements a feedback mechanism where the complex gain matrix is continuously updated based on measured cross-talk levels. The system assesses the correlation between input and output signals, determines the actual transfer function of the multiport amplifier, and adjusts the phase and gain of individual amplifier units to optimize isolation. This closed-loop feedback enables the system to maintain low cross-talk levels while operating at high power output.
Solution Approach 2:
The patent dynamically adjusts the operating parameters of the amplifier units, specifically their phase and gain characteristics. By changing these parameters based on the assessed cross-talk levels and the complex gain matrix model, the system optimizes the balance between power output and signal isolation. The ability to modify amplifier parameters in real-time allows the system to compensate for variations and maintain performance.
3Reliability
If extensive onboard hardware is used for tracking and compensation, then signal isolation is maintained, but processing payload on satellite increases
Solution Approach 1:
The patent creates a digital copy of the multiport amplifier's transfer function in the form of a complex gain matrix. This mathematical model replicates the amplifier's signal routing and isolation characteristics, allowing cross-talk assessment to be performed through digital signal processing rather than physical feedback hardware. The complex gain matrix serves as a virtual replica that enables isolation measurement without requiring additional onboard hardware.
Solution Approach 2:
The patent makes the digital signal processor perform multiple functions: it assesses cross-talk levels, determines the transfer function, updates the complex gain matrix, and controls amplifier adjustments. This multi-functional approach consolidates what would otherwise require separate dedicated hardware systems into a single versatile processing unit, reducing overall payload complexity while maintaining reliable isolation.
Data Source
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AI summary
In order to maintain isolation of signals within a multiport amplifier of a communications satellite and to reduce cross-talk components, by monitoring communications signals passing through the multiport amplifier, output signals of the multiport amplifier are sensed and downconverted to baseband, and applied to an emulator mechanism of the multiport amplifier. The emulator mechanism comprises a reverse matrix of the multiport amplifier, which recovers the input signals of the multiport amplifier together with cross-talk components, and a digital signal processor which carries out a frequency analysis of the cross-talk components by means of an FFT, and employs a digital model of the multiport amplifier to determine the state of the multiport amplifier which gives rise to such cross-talk components. The digital signal processor may be located at a ground station to which communication is made via a telemetry link.