Power Amplifier Linearizer Tuning for Multicarrier Intermodulation
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Solution Overview
Problem
Adjusting power amplifiers for satellite communications to minimize non-linearity effects on multicarrier signals is challenging, as conventional methods using two carriers of the same power are not optimal for multicarrier signals, leading to increased costs and complexity, especially when dealing with larger channel capacities and broader signal bands.
Innovation Solution
A method and system that input two signals of the same power into a power amplifier, measure and calculate the power sum of intermodulations, and adjust the linearizer to minimize the power sum of second-order intermodulations, optimizing the adjustment process for multicarrier signals by adjusting the linearizer parameters such as loss, phase, and amplification factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional two-carrier adjustment method is used, then adjustment simplicity is maintained, but adjustment accuracy for multicarrier signals deteriorates
Solution Approach 1:
The patent creates a virtual multicarrier signal model by calculating equivalent intermodulation power sums from two-carrier measurements. Instead of physically generating complex multicarrier signals for adjustment, the system copies the essential intermodulation characteristics through mathematical modeling, allowing accurate multicarrier optimization using simple two-carrier test equipment.
Solution Approach 2:
The patent transforms the adjustment criterion from direct multicarrier intermodulation measurement to an equivalent power sum calculation based on individual carrier intermodulation measurements. By changing the measurement and calculation parameters, the system achieves multicarrier optimization accuracy while maintaining two-carrier measurement simplicity.
2Measurement precision
If multicarrier signal generator is used for optimal adjustment, then adjustment accuracy improves, but system cost and complexity increase
Solution Approach 1:
Instead of using expensive multicarrier signal generators, the patent copies the multicarrier intermodulation characteristics through mathematical calculation from two-carrier measurements. The equivalent power sum model replicates the essential behavior of multicarrier signals, eliminating the need for complex physical signal generation equipment while maintaining adjustment accuracy.
Solution Approach 2:
The patent extracts the essential intermodulation characteristics from complex multicarrier signals and represents them through a simplified power sum calculation based on two-carrier measurements. This extraction approach separates the critical adjustment information from the complex signal structure, enabling accurate adjustment with simpler equipment.
3Reliability
If back-off is increased to suppress non-linearity, then linearity improves, but power consumption increases
Solution Approach 1:
The patent applies preliminary linearization through the linearizer before signals enter the power amplifier. By pre-compensating for non-linear effects using the adjustable linearizer, the system maintains linearity at higher power levels without requiring excessive back-off, thus reducing power consumption while preserving signal quality.
Solution Approach 2:
The patent implements an adjustment system that measures intermodulation products and uses this feedback to optimize the linearizer settings. By continuously monitoring and adjusting the linearizer parameters based on measured intermodulation levels, the system achieves optimal linearity with minimal back-off, preventing unnecessary power loss.
Data Source
AI summary
An object is to provide a method and a system of adjusting a power amplifier which makes it possible to adjust a linearizer using signals of two carriers by the same power, to reduce the influence of the non-linearity on a multicarrier signal compared with the conventional. A method of adjusting a power amplifier, the power amplifier including a linearizer to reduce an intermodulation caused by non-linearity of the power amplifier, includes: inputting two signals generated by a signal generator into the power amplifier; measuring power of each order of first intermodulations of the two signals output from the power amplifier; calculating a power sum of second intermodulations by the plurality of signals using the measured power of each order of the first intermodulations; and adjusting the linearizer so that the power sum of the second intermodulations by the plurality of signals takes a minimum value or at most a predetermined value.