Feed Forward RF Amplifier Delay Tuning for Wider Correction Bandwidth
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Solution Overview
Problem
Power amplifiers in RF communication systems introduce distortion that interferes with other channels, and existing solutions like feed forward error correction reduce operational bandwidth when trying to minimize distortion, especially in dynamic environments like Land Mobile Radio systems.
Innovation Solution
A power amplifier with a feed forward correction loop that includes a main amplifier, a delay element in the main path, and an error amplifier in the error path, along with a composite phase shifter to center the correction bandwidth, using a coaxial cable for fractional delay to reduce distortion and increase operational bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If feed forward error correction is used to reduce distortion, then distortion is reduced, but operational bandwidth is reduced
Solution Approach 1:
The patent implements dynamic delay adjustment in the error signal path, allowing the delay value to be changed based on operating conditions. This enables the system to maintain optimal correction performance across different bandwidth requirements by adapting the delay parameter rather than using a fixed delay value, thus resolving the contradiction between distortion reduction and bandwidth preservation.
Solution Approach 2:
The patent changes the delay parameter in the error signal path to optimize performance. By adjusting the delay value as a variable parameter rather than a fixed value, the system can achieve effective distortion cancellation while maintaining broader operational bandwidth, directly addressing the technical contradiction.
2Adaptability or versatility
If delay mismatch is reduced to increase correction bandwidth, then correction bandwidth is increased, but system complexity increases
Solution Approach 1:
The patent uses variable delay adjustment rather than complex adaptive algorithms to manage delay mismatch. By simply changing the delay parameter value based on operating conditions, the system achieves broader correction bandwidth without introducing significant complexity, avoiding the need for complex real-time optimization circuits.
Data Source
AI summary
Apparatus and method for extended operational bandwidth amplifiers with fractional instantaneous bandwidth feed forward correction. In one embodiment, the method includes amplifying a radio frequency (RF) input signal to provide an amplified RF signal and introducing a first delay in the amplified RF signal. The method also includes receiving an error signal of the amplified RF signal and centering a correction bandwidth with respect to the amplified RF signal. The method also includes amplifying the error signal and combining the amplified RF signal and the amplified error signal to reduce an error in the amplified RF signal. The first delay is smaller than a second delay caused by the error path.