Tunable Oscillator Reactance Switching for Stable Frequency Calibration
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Solution Overview
Problem
Existing tunable oscillators face accuracy issues due to changes in gain associated with tuning inputs, which affect the oscillation frequency, leading to inaccurate frequency synthesis in applications like frequency synthesizers, particularly in wireless networking technologies where rapid calibration is required.
Innovation Solution
A variable reactance apparatus is introduced, allowing multiple unit variable reactance structures to be shared between tuning inputs, maintaining constant effective reactance and frequency despite changes in gain, by selectively connecting these structures to tuning signals, thereby minimizing frequency shifts during calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gain associated with a tuning input is changed, then the tuning range or responsiveness is improved, but the oscillation frequency accuracy deteriorates
Solution Approach 1:
The variable reactance apparatus is divided into multiple unit variable reactance structures that can be independently controlled. Each unit structure can be selectively connected to different tuning inputs, allowing the total reactance to be segmented and redistributed among multiple tuning signals without changing the overall effective reactance, thus maintaining frequency accuracy while enabling gain changes.
Solution Approach 2:
The invention changes the distribution parameters of reactance among multiple tuning inputs while maintaining the total effective reactance constant. By adjusting which unit structures are connected to which tuning inputs, the gain associated with each tuning input can be changed without altering the oscillation frequency, resolving the contradiction between tuning adaptability and frequency accuracy.
2Productivity
If gain switching is performed during calibration, then the calibration speed is improved, but frequency stability deteriorates
Solution Approach 1:
The variable reactance structures are pre-configured and can be rapidly switched between different tuning inputs during calibration. The apparatus is designed to allow quick reconnection of unit structures to different tuning signals without causing frequency instability, enabling fast calibration while maintaining frequency stability through controlled switching sequences.
Solution Approach 2:
The unit variable reactance structures serve multiple functions by being able to connect to different tuning inputs. This multi-functionality allows the same hardware structures to be used for both frequency tuning and gain switching operations, enabling rapid calibration mode changes without requiring additional components that could compromise frequency stability.
3Device complexity
If multiple tuning inputs share variable reactance structures, then the device complexity is reduced, but the control precision deteriorates
Solution Approach 1:
By segmenting the variable reactance into multiple discrete unit structures, each with its own control input node, the invention achieves precise control over how reactance is distributed among tuning inputs. This segmentation allows independent control of each unit's connection, maintaining control precision while reducing overall device complexity through modular design.
Solution Approach 2:
The control circuit dynamically reconfigures the connections between unit variable reactance structures and tuning inputs based on operational requirements. This dynamic switching capability allows the system to adapt the distribution of reactance structures to different tuning inputs, maintaining precise control over effective reactance while using a unified shared structure that reduces device complexity.
Data Source
AI summary
A variable reactance apparatus, tunable oscillator and method for changing a gain associated with an input signal of a tunable oscillator are disclosed. An embodiment of the variable reactance apparatus includes a plurality of unit variable reactance structures including respective control input nodes, and a control circuit configured to connect each of the control input nodes to a respective signal from among a plurality of signals including a first tuning signal and a second tuning signal. An embodiment of a tunable oscillator includes a resonance circuit, a negative impedance structure and a variable reactance apparatus configured for tuning of the oscillator. An embodiment of a method includes altering connections of first and second tuning signals to control input nodes of respective first and second sets of unit variable reactance structures while holding constant a sum of the number of unit variable reactance structures in the first and second sets.