Accelerometer Self-Test Transfer Standard for High-Frequency Sensitivity
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Solution Overview
Problem
Accurately measuring the sensitivity of micromachined accelerometers at high frequencies is challenging due to difficulties in mechanically shaking them at such frequencies, making precise performance parameter determination problematic.
Innovation Solution
A method and system that perform self-tests on accelerometers by stimulating them with signals encoded at low frequencies, determining sensitivity, and using self-test equivalent acceleration as a transfer standard to assess parameters at high frequencies, allowing for accurate measurements without requiring high-frequency shaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical shaking is used to measure accelerometer sensitivity at high frequencies, then sensitivity measurement can be performed, but measurement precision deteriorates due to difficulty in accurately shaking at high frequencies
Solution Approach 1:
The patent replaces the mechanical shaking system with an electrical self-test stimulation system. Instead of using external mechanical vibration to stimulate the accelerometer, the invention uses electrical signals applied through self-test electrodes to directly stimulate the proof mass, enabling frequency-encoded self-test without mechanical contact or high-frequency shaking apparatus.
Solution Approach 2:
The patent introduces frequency-encoded self-test stimulation signals as an intermediary between the test equipment and the accelerometer. These signals are modulated at specific frequencies and applied through electrodes, serving as a mediator that transfers test information to the accelerometer without requiring direct mechanical coupling or high-frequency physical shaking.
2Measurement precision
If frequency-encoded self-test stimulation signals are used, then measurement precision at high frequencies is improved, but device complexity increases due to signal encoding and processing requirements
Solution Approach 1:
The patent employs periodic frequency-encoded self-test stimulation signals that are modulated at specific frequencies corresponding to the frequencies of interest. By using periodic signals with known frequency characteristics, the system can encode test information in the frequency domain, simplifying the processing required to extract sensitivity measurements at high frequencies.
Solution Approach 2:
The patent utilizes the natural vibrational response of the accelerometer proof mass when stimulated by frequency-encoded signals. By exciting the proof mass at specific frequencies and measuring its response, the system can determine sensitivity at those frequencies without requiring complex time-domain analysis or additional hardware components.
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
Enables easier and more accurate measurements of accelerometer sensitivity at high frequencies by using low-frequency self-tests as a basis for determining parameters, thereby overcoming the difficulty of high-frequency mechanical shaking.
Implementation Method 1
a first fixed electrode, a second fixed electrode, and a movable electrode positioned between first and second fixed electrode
Data Source
AI summary
A system, computer program product and method of obtaining a performance parameter associated with a sensor, such as an accelerometer, is provided. The method includes applying an acceleration to the accelerometer and a first frequency to obtain a sensitivity of the accelerometer at the first frequency. A first self-test is performed on the accelerometer. The first self-test includes stimulating the accelerometer with a first self-test stimulation signal encoded with the first frequency, such that the accelerometer outputs a first signal. A self-test equivalent acceleration is then determined based, at least in part, on the first signal and the accelerometer sensitivity at the first frequency. A second self-test is performed on the accelerometer. The second self-test includes stimulating the accelerometer with a second self-test stimulation signal encoded with the second frequency, such that the accelerometer outputs a second signal. A parameter of the accelerometer is determined at the second frequency based, at least in part, on the second signal and the self-test equivalent acceleration. The parameter may be sensitivity of the accelerometer at the second frequency.