Tunable Oscillator Reactance Sharing for Gain Switching Stability
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Solution Overview
Problem
Changing the gain associated with a tuning input in a tunable oscillator causes a change in oscillation frequency, reducing the accuracy of circuits like frequency synthesizers, and existing methods to increase gain for faster calibration introduce frequency shifts and complexity.
Innovation Solution
A variable reactance apparatus that shares unit variable reactance structures between two tuning inputs, allowing the effective reactance to remain constant while changing gain, using a bank of parallel connected variable reactance structures and control circuits to manage connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gain associated with a tuning input is changed to improve calibration speed, then calibration time is reduced, but oscillation frequency changes causing accuracy reduction
Solution Approach 1:
The patent changes the gain parameter of the tuning input by adjusting the capacitance values of varactor circuits. By modifying the capacitance parameters, the gain is adjusted to accelerate calibration while the system actively compensates to maintain frequency accuracy through coordinated control of multiple varactor circuits.
Solution Approach 2:
The patent implements a feedback mechanism where the system monitors the oscillation frequency and adjusts the varactor circuit configurations in response. This feedback loop ensures that when gain is changed for faster calibration, the frequency deviations are detected and corrected, maintaining measurement precision throughout the calibration process.
2Adaptability or versatility
If multiple separate variable reactance circuits are used for different tuning inputs, then gain switching is possible, but device complexity increases
Solution Approach 1:
The patent merges multiple variable reactance circuits into a shared bank of parallel-connected varactor circuits. Instead of having separate circuits for each tuning input, the invention combines them into a unified structure where varactor circuits can be selectively connected to different tuning inputs, reducing overall circuit complexity while maintaining gain switching capability.
Solution Approach 2:
The patent creates a universal varactor circuit bank that serves multiple tuning inputs simultaneously. Each varactor circuit in the parallel bank can be connected to different tuning inputs based on control signals, making the same hardware structure perform multiple functions and enabling gain switching without proportionally increasing complexity.
3Stability of the object's composition
If unit variable reactance structures are shared between tuning inputs, then effective reactance remains constant during gain changes, but control circuit complexity increases
Solution Approach 1:
The patent implements dynamic switching of varactor circuit connections using control circuits that respond to tuning input selections. The control circuits dynamically reconfigure which varactor circuits are connected to which tuning inputs, allowing the effective reactance to remain constant while enabling gain changes. This dynamic reconfiguration is managed through coordinated control signals that adjust the switching states based on the desired operating mode.
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
Maintains oscillator frequency stability while altering gain, reducing calibration time without introducing frequency shifts or complexity, thus enhancing the accuracy and efficiency of frequency synthesizers.
Implementation Method 1
A variable reactance apparatus is disclosed that shares unit variable reactance structures between two tuning inputs of an oscillator
Data Source
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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 comprises a plurality of unit variable reactance structures comprising 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 comprising a first tuning signal and a second tuning signal. An embodiment of a tunable oscillator comprises a resonance circuit, a negative impedance structure and a variable reactance apparatus configured for tuning of the oscillator. An embodiment of a method comprises 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.