Multi-Carrier Phase Alignment for Intermodulation Distortion Reduction
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Solution Overview
Problem
Existing methods for generating combined carrier signals from numerically controlled oscillators often result in inter-modulation distortion products due to frequency alterations of carrier waves during transmission.
Innovation Solution
A method that adjusts the initial phase of output carrier waves from multiple numerically controlled oscillators to minimize peak amplitude and reduce inter-modulation distortion products, using phase alignment circuitry to recalibrate and maintain optimal phase relationships among the carrier waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple numerically controlled oscillators are combined to generate a combined carrier signal, then the frequency flexibility and signal generation capability are improved, but inter-modulation distortion products are generated due to phase misalignment
Solution Approach 1:
The patent changes the phase parameter of each oscillator's output signal by introducing adjustable phase shifters. By modifying the phase parameter rather than the frequency, the system maintains frequency flexibility while eliminating inter-modulation distortion through proper phase alignment of the combined carrier signal.
Solution Approach 2:
The patent implements a feedback mechanism where the combined output signal is monitored for phase alignment, and the phase shifters are adjusted accordingly to minimize inter-modulation distortion products. This closed-loop approach ensures that the harmful distortion is continuously reduced while maintaining the desired frequency characteristics.
2Object-generated harmful factors
If the initial phase of carrier waves is adjusted to minimize peak amplitude, then inter-modulation distortion is reduced, but additional phase alignment circuitry and control mechanisms are required
Solution Approach 1:
The patent applies preliminary phase adjustment through phase shifters before the signals are combined. By pre-aligning the phases of individual oscillator outputs before combination, the system minimizes peak amplitude and reduces inter-modulation distortion at the source, rather than requiring complex post-processing circuitry.
Solution Approach 2:
The phase shifter acts as an intermediary element between each oscillator and the combination point. This intermediary component enables precise phase control of each signal path, facilitating optimal phase alignment and distortion reduction without requiring complex interaction between multiple oscillators.
Data Source
AI summary
A method is provided for reducing inter modulation distortion products using multi-carrier phase alignment of the type where a combined carrier signal is generated from the combined output carried waves of a plurality of numerically controlled oscillators in which the frequency of the carrier wave can be altered by changing an input value into the oscillator. In particular the initial phase of the output carrier waves is adjusted so that the peak amplitude of the combined carrier signal is minimized so that compression of the higher amplitude portions of the combined signal is reduced.