Power Amplifier Bias Feedback for Symmetrical Output Waveforms
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Solution Overview
Problem
Power amplifiers used in wireless communication face challenges in preventing the occurrence of even-order harmonic components in their output signals, which are not effectively addressed by existing technologies.
Innovation Solution
The power amplifier incorporates a feedback circuit that adjusts the bias signals to match the average DC voltage of the output signal with a reference voltage, ensuring the waveform is point symmetrical, thereby reducing even-order harmonics through a configuration including a signal generator, inverters, a feedback circuit, and a bias supply circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a conventional power amplifier is used, then the output signal is generated, but even-order harmonic components occur in the output signal
Solution Approach 1:
The patent implements a feedback circuit that detects the output signal from the power amplifier and feeds it back to adjust the bias signal. This closed-loop feedback mechanism dynamically compensates for even-order harmonic components by adjusting the bias voltage based on the detected output signal characteristics, thereby improving signal quality and reducing harmful harmonic distortions.
Solution Approach 2:
The patent changes the bias signal parameters (voltage level and timing) dynamically to achieve point-symmetrical waveforms. By adjusting the bias signal amplitude and timing in response to output signal conditions, the system transforms the operating parameters to eliminate even-order harmonics while maintaining reliable signal generation.
2Reliability
If the bias signal is adjusted to reduce even-order harmonics, then signal quality improves, but the complexity of the circuit increases
Solution Approach 1:
The feedback circuit provides automatic adjustment of the bias signal based on output signal detection, eliminating the need for complex manual tuning circuits or multiple adjustment components. The self-regulating feedback mechanism achieves signal quality improvement with minimal additional circuitry.
Solution Approach 2:
The power amplifier system performs self-adjustment through the feedback mechanism, where the output signal itself is used to regulate the bias condition. This self-service approach reduces the need for external control circuits or additional complexity while maintaining high signal quality.
Data Source
AI summary
A power amplifier includes an output signal generator constructed to generate, on the basis of an input AC signal, an output signal including, in cycles, a first pulse being width higher in voltage than a first reference voltage and a second pulse being width lower in voltage than the first reference voltage and a feedback circuit constructed to generate a first bias signal corresponding to the output signal and feed back the first bias signal to an input side of the output signal generator to equalize a width of the first pulse and a width of the second pulse in the cycles of the output signal.