Polar RF Power Amplifier With Pulse Supply Modulation Linearity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power amplifiers in radio communication devices face challenges in achieving high power efficiency while maintaining signal linearity, as existing polar modulation techniques struggle to satisfy wide band characteristics, high voltage operation, low noise, and high power efficiency simultaneously, often resulting in distortion and increased circuit complexity.
Innovation Solution
A power amplifier structure that includes a polar modulator, a direct current power supply, a pulse modulator, a pulse amplification circuit, a combining circuit, a low pass filter, and an RF amplifier, which pulse-modulates and amplifies the amplitude component signal, adding a direct current voltage to the output signal to suppress distortion and improve power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the power amplifier is operated in a high back-off state to maintain signal linearity, then the linearity between input and output signals is improved, but the power efficiency is reduced
Solution Approach 1:
The invention segments the amplitude modulation signal into multiple frequency components (base band and high frequency components). By separating and independently processing these components through different paths (linear amplification for base band, efficient amplification for high frequency), the system achieves both signal linearity and improved power efficiency simultaneously
Solution Approach 2:
The invention dynamically adjusts the operating state by switching between different amplification modes based on signal characteristics. The power amplifier operates in high back-off state for linearity when needed, and can utilize more efficient operating states for high frequency components, adapting to different signal conditions to optimize both linearity and power efficiency
2Use of energy by moving object
If polar modulation techniques are used to improve power efficiency, then the power efficiency is improved, but distortion occurs in the output signal
Solution Approach 1:
The invention introduces a high frequency component signal as an intermediary element. This high frequency signal serves as a carrier that modulates the amplitude component, enabling efficient power amplification while the base band signal maintains linearity. The intermediary high frequency component allows the system to achieve power efficiency improvements without introducing significant distortion to the original modulated signal
Solution Approach 2:
The invention changes the frequency parameter by introducing high frequency components into the modulation process. By operating at elevated frequencies for certain signal components, the system can utilize more efficient amplification techniques while maintaining overall signal integrity through proper synthesis of the base band and high frequency components
3Use of energy by moving object
If a power supply modulator is added to achieve high power efficiency, then the power efficiency is improved, but the circuit size increases
Solution Approach 1:
The high frequency component signal generator is designed to serve multiple functions: it generates the high frequency carrier signal needed for efficient modulation, provides the frequency shift necessary for power efficiency improvements, and can be integrated with existing RF circuitry. This multi-functional design achieves power efficiency gains without proportionally increasing circuit size
Solution Approach 2:
The invention merges the high frequency component generation function with the existing power amplifier and modulation circuitry. By combining these functions into an integrated architecture rather than adding completely separate blocks, the circuit achieves improved power efficiency while minimizing the increase in overall circuit size
Data Source
AI summary
A power amplifier that amplifies an RF modulation signal containing an amplitude modulation component and a phase modulation component, including a polar modulator that outputs an amplitude component signal that is the amplitude modulation component of the RF modulation signal, a direct current power supply that outputs a direct current voltage, a pulse modulator that pulse-modulates the amplitude component signal, a pulse amplification circuit that amplifies a pulse modulation signal, a combining circuit that adds a direct current voltage that is outputted from the direct current power supply to an output signal of the pulse amplification circuit, a low pass filter that smoothens an output signal of the combining circuit, and an RF amplifier that not only amplifies the RF modulation signal, but also amplitude-modulates the amplified signal with an output signal of the low pass filter and outputs the resultant signal.