Injection-Locked Displacement Detection With Lower-Frequency Demodulation
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Solution Overview
Problem
Detectors using the Doppler effect for displacement detection face challenges with high-frequency signal processing, leading to reduced signal noise ratio (SNR) due to flicker noise and high power consumption from high-frequency oscillation sources.
Innovation Solution
A detector design incorporating a frequency multiplier that uses injection locking and pulling to generate output signals at lower frequencies, reducing power consumption and mitigating flicker noise effects by performing demodulation at intermediate frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high frequency oscillation source is used to detect displacement by the Doppler effect, then the displacement detection capability is improved, but the power consumption increases and flicker noise affects the signal quality
Solution Approach 1:
The patent divides the frequency multiplication process into multiple stages using cascaded frequency multipliers (e.g., doubling frequency twice to achieve 4x multiplication). This segmentation allows each stage to operate at manageable frequency levels rather than requiring a single high-frequency oscillation source, thereby reducing overall power consumption while maintaining the capability to generate high-frequency detection signals.
Solution Approach 2:
The patent introduces intermediate frequency signals as mediators between the low-frequency oscillation source and the high-frequency detection requirement. Frequency multipliers act as intermediary devices that progressively transform the base frequency into the required high frequency, avoiding direct generation of high-frequency signals and reducing the power consumption burden on the oscillation source.
2Measurement precision
If a high frequency oscillation source is used to detect displacement by the Doppler effect, then the displacement detection capability is improved, but the signal noise ratio is reduced due to flicker noise
Solution Approach 1:
By segmenting the frequency multiplication into multiple lower-stage processes rather than a single high-frequency generation step, the patent reduces the impact of flicker noise. Each frequency multiplication stage operates at a lower frequency where flicker noise has less impact, and the cumulative effect preserves signal quality better than direct high-frequency operation.
Solution Approach 2:
The patent performs frequency multiplication in advance through multiple staged operations before the final detection process. This preliminary action at lower frequencies minimizes the introduction of flicker noise, and the high-frequency signal required for Doppler detection is achieved through cumulative frequency transformation rather than direct high-frequency generation.
3Measurement precision
If a high frequency oscillation source is used, then the displacement detection capability is improved, but the difficulty of digital signal processing increases
Solution Approach 1:
The patent performs frequency multiplication and signal preparation in advance through multiple staged frequency multipliers before the signal reaches the digital processing stage. This preliminary action transforms the signal into a form that is more suitable for digital processing, reducing the complexity of subsequent digital signal operations while maintaining the high-frequency characteristics needed for accurate displacement detection.
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 solution effectively reduces power consumption and minimizes the impact of flicker noise, improving the signal-to-noise ratio and facilitating easier digital signal processing by operating at lower frequencies.
Implementation Method 1
The frequency multiplier outputs the output signal at a frequency equal to a multiple of the first frequency by injection locking
Implementation Method 2
The frequency multiplier pulls the output signal to the second frequency by injection pulling
Implementation Method 3
a detector detecting the status of displacement of an object by the Doppler effect
Data Source
AI summary
A detector includes an oscillation source, a frequency multiplier, a transceiver and a demodulator. The oscillation source generates a first injection signal with a first frequency. The frequency multiplier receives the first injection signal, outputs an output signal and receives a second injection signal with a second frequency. The frequency multiplier uses injection locking to lock a frequency of the output signal at a multiple of the first frequency, and uses injection pulling to pull the frequency of the output signal to the second frequency. The transceiver transmits the output signal and receives a received signal with a third frequency for updating the second injection signal. The demodulator performs a demodulation operation according to the output signal so as to generate a displacement signal.