Reactive Multiphase Transmitter Combiner for Harmonic Cancellation
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Solution Overview
Problem
Multiphase pulse modulated transmitters using resistive combiners suffer from power inefficiency due to power dissipation when combining signals with amplitude and phase differences, and reactive combiners lack isolation between power amplifier outputs, affecting amplifier operation.
Innovation Solution
A reactive combiner is used to cancel out signals with 180-degree phase differences and scale power output based on the number of active power amplifiers by configuring branches with specific impedances, allowing efficient combination and isolation-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistive combiner is used to combine signals from multiple power amplifiers, then the signals can be combined with isolation between amplifier outputs, but power is dissipated reducing transmitter efficiency
Solution Approach 1:
The patent changes the impedance parameter of the combiner from resistive to reactive (specifically using inductive or capacitive elements with specific reactance values). This parameter change allows the combiner to present appropriate impedance to each amplifier output without dissipating power, as reactive elements store and release energy rather than converting it to heat.
Solution Approach 2:
The patent converts the potentially harmful effect of signal interference between amplifiers into a beneficial isolation mechanism. By using reactive elements with specific reactance values, the combiner creates impedance conditions that naturally prevent signal leakage between amplifier outputs without requiring resistive isolation that would dissipate power.
2Loss of energy
If a reactive combiner is used to combine signals without power dissipation, then transmitter efficiency improves, but isolation between power amplifier outputs is lost affecting amplifier operation
Solution Approach 1:
The patent carefully selects specific reactance values for the reactive elements in the combiner. By adjusting these impedance parameters, the combiner maintains proper isolation between amplifier outputs while still using reactive (non-dissipative) elements. The specific reactance values are chosen to create the desired impedance conditions for both signal combination and amplifier isolation.
3Ease of operation
If resistive combiners are used to combine multiple amplifier outputs, then signal combining is achieved, but transmitter power efficiency deteriorates
Solution Approach 1:
The patent changes the fundamental nature of the combiner from resistive to reactive by selecting specific reactance values for the reactive elements. This parameter change enables the combiner to perform signal combining functions while avoiding power dissipation, thereby maintaining transmitter power efficiency. The reactive combiner achieves the same signal combining capability without the energy loss inherent in resistive combiners.
4Power
If reactive combiners with specific impedances are used, then power output scales with number of active amplifiers, but combiner design complexity increases
Solution Approach 1:
The patent divides the combiner into separate reactive branches, each connected to a specific amplifier output. Each branch contains reactive elements with specific reactance values that are independently selectable. This segmentation allows the combiner to handle multiple amplifier outputs separately and combine them efficiently, with each branch contributing to the scalable power output while maintaining manageable design complexity through modular structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves power-efficient cancellation of odd harmonics and scalable output power with the number of active amplifiers, improving transmitter efficiency and operation across various states.
Implementation Method 1
the reactive combiner is configured to cancel out signals exhibiting a 180 degree phase difference
Data Source
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AI summary
A multiphase transmitter including a reactive combiner for combining amplified pulse modulated signals generated by multiple power amplifiers of the transmitter. In some embodiments, the reactive combiner is configured to inhibit odd order harmonics of the amplified pulse modulated signals in a power efficient manner.