RF Switch Linearizer Arm for Intermodulation Distortion Cancellation
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Solution Overview
Problem
Non-linearities in communication device circuitry cause harmonic and intermodulation distortion, leading to challenges in maintaining signal isolation and interference in multichannel communication equipment.
Innovation Solution
A radio-frequency switch with a switch arm and a linearizer arm, where the linearizer arm compensates for non-linearity effects by generating distortion products opposite in phase to those generated by the switch arm, reducing third-order intermodulation and harmonic distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switch arm with transistors is used to route radio-frequency signals, then signal switching capability is improved, but non-linearity distortion increases
Solution Approach 1:
The patent converts the harmful non-linear distortion generated by the switch arm into a beneficial effect by using a linearizer arm that generates equal but opposite distortion products. This destructive interference cancels out the unwanted distortion, transforming the problem of non-linearity into a solution where the distortion is actively compensated and eliminated from the output signal.
Solution Approach 2:
The linearizer arm acts as an intermediary component between the switch arm and the output. It introduces a compensating signal path that generates distortion products specifically designed to counteract the non-linearities of the switch arm, thereby mediating the harmful effects without eliminating the necessary switching function.
2Power
If multiple transistors are stacked in the switch arm to improve signal handling, then power handling capability is improved, but non-linearity effects increase
Solution Approach 1:
The linearizer arm converts the harmful non-linear effects generated by the stacked transistors into a beneficial cancellation mechanism. By generating distortion products that are equal in magnitude but opposite in phase to those produced by the switch arm, the system transforms the power-related non-linearities into a self-correcting phenomenon.
Solution Approach 2:
The patent changes the operating parameters of the transistors by applying specific biasing voltages to the linearizer arm transistors. This allows the linearizer transistors to operate in a region where they generate the desired compensating non-linearities, effectively changing their functional parameters to achieve distortion cancellation while maintaining proper switching operation.
3Object-generated harmful factors
If a linearizer arm is added to compensate non-linearity, then distortion reduction is improved, but device complexity increases
Solution Approach 1:
The patent segments the switch function into two independent arms: the switch arm for signal routing and the linearizer arm for distortion compensation. This segmentation allows each arm to be optimized for its specific function while working together as a unified system, reducing overall complexity by separating concerns rather than trying to achieve both switching and linearization in a single complex circuit.
Solution Approach 2:
The linearizer arm performs multiple functions: it compensates for non-linear distortion, maintains signal integrity, and works across different signal power levels. This multi-functionality reduces the need for additional separate compensation circuits, thereby managing complexity while achieving comprehensive distortion reduction.
Data Source
AI summary
Circuits, systems, and methods to compensate for non-linearities associated with a switching circuit are discussed herein. For example, a switch circuit can include a switch arm and a linearizer arm. The switch arm can have a first transistor connected between an input node and an output node. The switch arm can be configured to receive a radio-frequency signal. The linearizer arm can have a second transistor connected to at least one of a gate or a body of the first transistor. The linearizer arm can be configured to compensate a non-linearity effect generated by the switch arm.