Gyro Sensor Digital Filtering for Detuning Frequency Attenuation
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Solution Overview
Problem
Existing gyro sensors face challenges in effectively attenuating detuning frequencies without causing signal delay or increasing circuit complexity and cost, particularly when using low pass filters or generating and subtracting detuning frequency signals.
Innovation Solution
A detection device incorporating a drive circuit, detection circuit, and digital signal processing unit that employs band elimination filtering to attenuate detuning frequencies by setting the center frequency of the band elimination filter to the detuning frequency, thereby preventing signal delay and reducing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low pass filter with a low cutoff frequency is used to remove the unnecessary signal of the detuning frequency, then the unnecessary signal is attenuated, but the signal band becomes narrow
Solution Approach 1:
The patent divides the filtering function into two separate filters: a band elimination filter specifically targeted at the detuning frequency and a low pass filter for the signal band. This segmentation allows each filter to operate independently with optimized parameters, eliminating the need to compromise between narrow band elimination and wide signal passage.
Solution Approach 2:
The patent applies different filtering characteristics to different frequency regions: a sharp notch filter characteristic locally at the detuning frequency and a gentle low pass characteristic across the signal band. This local quality approach allows maximum attenuation at the harmful frequency while preserving the overall signal band width.
2Adaptability or versatility
If the cutoff frequency is increased to secure the signal band, then the signal band is widened, but a high-order filter is necessary which causes a large amount of signal delay
Solution Approach 1:
The patent separates the filtering tasks into two independent filters with different orders and functions. The band elimination filter handles detuning frequency removal with minimal delay, while the low pass filter handles signal band limitation with a higher order if needed. This segmentation eliminates the cumulative delay problem of a single high-order filter.
Solution Approach 2:
The band elimination filter acts as an intermediary stage that removes the detuning frequency component before the signal enters the low pass filter. This intermediate filtering step prevents the need for the low pass filter to work harder, reducing overall signal delay.
3Object-affected harmful factors
If a method for generating the detuning frequency signal and subtracting it from the original signal is used, then the unnecessary signal is removed, but the circuit becomes complicated and the circuit size becomes large
Solution Approach 1:
The patent replaces the mechanical/subtractive approach of generating and subtracting detuning frequency signals with a direct filtering approach using a band elimination filter. This substitution simplifies the circuit by eliminating the need for signal generation and subtraction circuits, achieving the same harmful signal removal more efficiently.
Solution Approach 2:
The band elimination filter serves as an intermediary component that directly attenuates the detuning frequency without requiring the complex sequence of signal generation, gain adjustment, and subtraction operations. This intermediary filtering approach reduces circuit complexity while achieving the same noise removal objective.
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
The proposed solution efficiently attenuates detuning frequencies while minimizing signal delay and circuit complexity, allowing for effective noise removal without the need for high-order filters or complex circuit designs.
Implementation Method 1
the digital signal processing unit performs band elimination filtering for attenuating a component of a detuning frequency Δf=|fd−fs| corresponding to a difference between a drive side resonance frequency fd and a detection side resonance frequency fs of the vibrator for the detection data
Implementation Method 2
A gyro sensor for detecting a physical quantity that changes due to external factors is assembled in an electronic apparatus such as a digital camera or a smart phone, or a moving object such as a vehicle or an airplane. The gyro sensor detects a physical quantity such as an angular velocity
Implementation Method 3
In the vibration gyro sensor, a physical quantity corresponding to a Coriolis force generated by rotation is detected
Data Source
AI summary
A detection device includes: a drive circuit that receives a feedback signal from a vibrator and drives the vibrator; a detection circuit that performs detection based on a signal from the vibrator and outputs detection data; and a digital signal processing unit that performs digital filtering for the detection data from the detection circuit. The digital signal processing unit performs band elimination filtering for attenuating a component of a detuning frequency Δf=|fd−fs| corresponding to a difference between a drive side resonance frequency fd and a detection side resonance frequency fs of the vibrator for the detection data.