Beat Oscillator Sensor for High-Resolution Resistance Measurement
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Solution Overview
Problem
Existing sensor devices face challenges in detecting small changes in environmental parameters due to limited resolution and increased noise sensitivity, especially at low voltage, and require large circuit scales to achieve high resolution and wide dynamic range detection.
Innovation Solution
A sensor device incorporating a beat oscillator with multiple oscillators generating a beat signal whose frequency changes with resistance value changes, improving resolution and dynamic range detection without increasing circuit complexity by converting resistance changes into frequency or period changes, which are then counted for precise measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the output bit number of the A/D converter is increased to improve resolution, then the resolution of the sensor output is improved, but the data width of the sensor output is widened and processing load is increased
Solution Approach 1:
The patent changes the measurement parameter from direct resistance value (requiring high-bit A/D conversion) to frequency/period of beat signal. This parameter transformation allows high-resolution measurement using simple frequency counting, avoiding the need for high-bit A/D converters and reducing data processing complexity
2Measurement precision
If the output bit number of the A/D converter is increased to improve resolution at low voltage, then the resolution is improved, but the minimum detecting voltage unit is reduced and noise sensitivity increases
Solution Approach 1:
The patent transforms the measurement from voltage-based (prone to noise at low voltage) to frequency-based (immune to voltage noise). The beat oscillator converts resistance changes into frequency changes, which can be counted with high resolution without being affected by voltage fluctuations or noise
Solution Approach 2:
The patent replaces the electrical measurement system (voltage-to-digital conversion) with a frequency-based measurement system (oscillation-to-counting). This substitution eliminates the vulnerability to voltage noise while achieving high resolution through simple digital counting of beat signal periods
3Measurement precision
If analog circuits for adjusting gain or offset are added to achieve high resolution and wide dynamic range, then the detection capability is improved, but the circuit scale becomes relatively large
Solution Approach 1:
The patent replaces complex analog adjustment circuits (gain/offset amplifiers) with a simple beat oscillator and frequency counter system. The analog circuit approach requires multiple amplification stages and adjustment components, while the frequency-based approach achieves the same measurement capability with minimal circuitry
Solution Approach 2:
The patent changes the measurement parameter from resistance (requiring analog signal conditioning) to frequency (amenable to direct digital counting). This parameter transformation eliminates the need for analog gain/offset adjustment circuits while achieving high resolution and wide dynamic range through frequency measurement
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 sensor device achieves high-resolution, wide-range detection of environmental changes with improved accuracy and reduced noise sensitivity, even at low voltage, using a small-scale digital circuit construction that does not require analog gain or offset adjustments.
Implementation Method 1
a beat oscillator 30 having plural oscillators of different oscillating frequencies. The beat oscillator 30 generates a beat signal of a frequency lower than oscillating frequencies by a difference of the oscillating frequencies
Data Source
AI summary
A sensor device is disclosed that includes a sensor, in which a resistance value is changed in accordance with a change in an environment of the sensor. The sensor device also includes a beat oscillator having plural oscillators of different oscillating frequencies. The beat oscillator generates a beat signal of a frequency lower than the oscillating frequencies. The beat signal corresponds to a difference of the oscillating frequencies. The beat oscillator is electrically connected to the sensor such that the frequency of the beat signal changes in accordance with the changes in the resistance value of the sensor.