Satellite Payload Channel Calibration Without Service Interruption
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Solution Overview
Problem
Multichannel transmission systems face challenges in calibrating radiofrequency chains and multiport amplifiers to correct defects in frequency responses and isolation, often requiring service interruptions or compromising calibration precision due to limitations in existing calibration methods.
Innovation Solution
A multichannel transmission system with a digital device implementing a multiple-input, multiple-output input hybrid network and distinct equalization filters, generating a calibration signal that occupies the entire spectral band, allowing precise calibration of frequency conversion chains and multiport amplifiers without service interruption by minimizing differences between generated and measured calibration signals across the entire frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a calibration signal is injected at low power to be superposed on the useful signal and avoid service interruption, then service continuity is maintained, but the measurement precision is degraded due to low signal-to-noise ratio
Solution Approach 1:
The calibration signal is injected in periodic bursts synchronized with the useful signal transmission. The calibration signal is transmitted only during specific time intervals when the useful signal is present, allowing calibration measurements to be performed without requiring service interruption. This periodic injection maintains service continuity while enabling calibration functionality.
Solution Approach 2:
The system uses feedback processing to extract and measure the calibration signal from the composite signal containing both useful signal and calibration signal. The measured calibration signal is compared with the known injected calibration signal to determine channel defects, enabling precision calibration even when the calibration signal power is low and superposed on the useful signal.
2Measurement precision
If the calibration signal occupies the entire spectral band to achieve high frequency resolution, then frequency response calibration precision is improved, but interference with useful signals increases
Solution Approach 1:
The calibration signal is transmitted in periodic time intervals rather than continuously. During calibration periods, the calibration signal occupies the entire spectral band to enable high-frequency resolution calibration measurements. During non-calibration periods, only the useful signal is transmitted, eliminating interference. This time-division approach allows full spectral utilization during calibration while preventing continuous interference with useful signals.
Solution Approach 2:
The calibration signal is injected at the beginning of each calibration interval before useful signal transmission begins. This preliminary injection allows the system to complete calibration measurements across the entire frequency band before useful signal transmission starts, ensuring high-frequency resolution calibration is achieved without subsequent interference with useful signals.
Data Source
AI summary
A multichannel transmission system which includes a calibration functionality that allows precise calibration of the frequency conversion chains and of the multiport amplifier of the system to be performed without interruption of service. The proposed calibration makes it possible to correct the defects over the entire frequency band of the system.