RF Transmitter Switching Architecture for High-Efficiency Emission
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Solution Overview
Problem
Existing RF transmitter architectures face inefficiencies due to power stages operating in linear mode, leading to low power transmission efficiency and increased noise, which complicates cosite use and requires additional band-pass filters, resulting in signal losses.
Innovation Solution
The proposed architecture uses power transistors as switches in blocked/saturated mode, with a switching cell controlled by complementary PWM signals, allowing only one cell to be activated at a time, reducing power dissipation and noise, and incorporating a low-pass filter to retain the desired RF frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If power stages operate in linear mode to meet linearity requirements, then linearity is improved, but power transmission efficiency deteriorates (efficiency drops to approximately 25%)
Solution Approach 1:
The invention changes the operating parameter of power transistors from linear mode to switching mode (cutoff/saturation), fundamentally altering how the transistors operate. This parameter change enables the system to achieve both high efficiency and acceptable linearity through PWM control of the switching elements.
Solution Approach 2:
The invention employs pulse-width modulation (PWM) to control switching transistors, using periodic switching actions at frequencies much higher than the modulated signal frequency. This periodic switching allows the system to achieve linear amplification characteristics while maintaining high efficiency, as the transistors operate in efficient switching mode rather than continuous linear mode.
2Object-affected harmful factors
If bandpass filters are added to reject interference and reduce noise, then noise rejection is improved, but signal losses increase due to substantial losses at each amplification stage
Solution Approach 1:
The invention converts the typically harmful switching transients and high-frequency components generated by switching transistors into useful spectral replicas of the modulated signal. By switching at frequencies much higher than the modulated signal frequency, the switching action creates multiple spectral copies of the desired signal, which can then be filtered to achieve both noise rejection and maintain signal strength.
Data Source
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AI summary
The idea of the present invention is to provide an RF signal-emitting architecture that solves or minimizes at least the aforementioned problems. For this purpose, power transistors will be used as switches in a blocked/saturated mode, while the prior art uses these transistors in linear mode. This is achieved by the use of two complementary signals for controlling a switching cell.