Adaptive Oscillator Tuning for Vibration-Induced Phase Noise
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Solution Overview
Problem
Mechanical acceleration causes significant phase noise sidebands in electronic devices due to microphonics, affecting oscillators and propagating through systems, leading to errors in signal transmission and requiring costly mechanical isolation structures.
Innovation Solution
A system with a reference oscillator and an accelerometer on the same platform detects mechanical acceleration, generating a tuning control signal using an adaptive filter assembly with adjustable weights based on comparisons between the oscillator output and external signals to minimize noise, allowing for the use of lower-cost, non-ruggedized oscillators without increased noise or weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mechanical isolation structures are used to protect the reference oscillator from vibration, then microphonic noise is reduced, but device weight and cost increase
Solution Approach 1:
The patent replaces mechanical isolation structures with an electronic compensation system consisting of an accelerometer, adaptive filter, and frequency adjustment mechanism. The accelerometer detects vibration, the adaptive filter processes the signal to determine compensation parameters, and the frequency reference adjusts the oscillator frequency electronically to cancel microphonic noise effects without mechanical isolation
Solution Approach 2:
The patent introduces an intermediary electronic compensation system between the vibration source and the oscillator. The accelerometer measures vibration, the adaptive filter computes compensation parameters, and the frequency adjustment mechanism applies corrections to the oscillator frequency, serving as an electronic mediator that eliminates the need for direct mechanical protection
2Object-affected harmful factors
If mechanical isolation structures are used to protect the reference oscillator from vibration, then microphonic noise is reduced, but device cost increases
Solution Approach 1:
The patent replaces expensive mechanical isolation structures with a cost-effective electronic compensation system using standard components (accelerometer, adaptive filter, frequency reference). This electronic approach achieves the same noise reduction function at lower manufacturing cost and complexity
3Measurement precision
If adaptive filter weights are adjusted based on oscillator output and external signal comparison, then noise cancellation accuracy is improved, but system complexity increases
Solution Approach 1:
The patent implements feedback by comparing the oscillator output signal with an external reference signal and using the difference to adjust the adaptive filter weights. This closed-loop feedback mechanism continuously optimizes the filter parameters to maintain accurate noise cancellation despite changes in oscillator characteristics over time or during fabrication
Solution Approach 2:
The patent dynamically changes the filter weights parameter based on real-time comparison between oscillator output and external signal. This adaptive parameter adjustment allows the system to compensate for manufacturing variations and drift over time, improving accuracy without requiring complex fixed hardware structures
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
This solution effectively reduces microphonic noise without the need for mechanical isolation, compensating for variations in oscillator response over time and during fabrication, while maintaining system accuracy and reducing testing time.
Implementation Method 1
an accelerometer on a same platform as the reference oscillator, such that mechanical acceleration at the reference oscillator is detected at the accelerometer to produce a measured acceleration
Implementation Method 2
A filter assembly, having an associated set of filter weights, receives the measured acceleration from the accelerometer and provides a tuning control signal responsive to the measured acceleration
Implementation Method 3
An adaptive weighting component receives the oscillator output signal of the reference oscillator and an external signal that is provided from a source external to the platform and adjusts the set of filter weights for the filter assembly based on a comparison of the external signal and the oscillator output signal
Data Source
AI summary
Systems and methods are provided for compensating for mechanical acceleration at a reference oscillator. A reference oscillator provides an oscillator output signal and an accelerometer on a same platform as the reference oscillator, such that mechanical acceleration at the reference oscillator is detected at the accelerometer to produce a measured acceleration. A filter assembly, having an associated set of filter weights, receives the measured acceleration from the accelerometer and provides a tuning control signal responsive to the measured acceleration to a frequency reference associated with the system. An adaptive weighting component receives the oscillator output signal of the reference oscillator and an external signal that is provided from a source external to the platform and adjusts the set of filter weights for the filter assembly based on a comparison of the external signal and the oscillator output signal.