Injection-Locked Doppler Displacement Detector With Low-Frequency Oscillator
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Solution Overview
Problem
High-frequency Doppler effect detectors face challenges with high power consumption and significant flicker noise interference due to the need for analog signal processing, which complicates digital signal processing and reduces signal-to-noise ratio.
Innovation Solution
A detector incorporating a frequency multiplier with injection locking and pulling mechanisms, reducing the oscillation source frequency and using intermediate frequencies for demodulation to minimize flicker noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an oscillation source operates at high frequency to detect displacement by Doppler effect, then detection capability is improved, but power consumption increases and flicker noise interference worsens
Solution Approach 1:
The patent segments the frequency operation into two stages: a low-frequency oscillation source generates a base signal, and a frequency multiplier circuit (comprising mixing circuits and resonant circuits) multiplies the frequency to achieve the required high-frequency detection signal. This segmentation allows the oscillation source to operate at low frequency (reducing power consumption) while the detection signal operates at high frequency (maintaining detection capability).
Solution Approach 2:
The patent introduces an intermediate low-frequency signal as a mediator between the oscillation source and the high-frequency detection signal. The oscillation source generates a low-frequency signal that serves as an intermediary, which is then processed by frequency multiplication circuits to produce the high-frequency signal needed for Doppler effect detection, thereby avoiding direct high-frequency operation of the oscillation source.
2Productivity
If high frequency signal is used for displacement detection, then detection status update capability is improved, but analog signal processing complexity increases and digital signal processing becomes more difficult
Solution Approach 1:
The patent performs preliminary frequency multiplication and signal preparation in advance before the main detection and digital processing stages. The frequency multiplier circuit pre-processes the low-frequency signal from the oscillation source, converting it to the required high-frequency signal format, thereby simplifying subsequent digital signal processing operations and reducing overall system complexity.
3Measurement precision
If oscillation source operates at high frequency around 10GHz, then displacement detection accuracy is improved, but power consumption cannot be decreased
Solution Approach 1:
The patent inverts the conventional approach by not having the oscillation source operate directly at high frequency. Instead, the oscillation source operates at low frequency, and the high-frequency signal is generated through frequency multiplication of the low-frequency signal, thereby achieving high-frequency detection capability while maintaining low-power oscillation source operation.
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 mitigates flicker noise interference, improving signal-to-noise ratio and simplifying digital signal processing by operating at lower frequencies and using intermediate frequencies for demodulation.
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
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
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AI summary
A detector (200) includes an oscillation source (210), a frequency multiplier (220), a transceiver (230) and a demodulator (240). The oscillation source (210) generates a first injection signal (Vi1) with a first frequency (f1). The frequency multiplier (220) receives the first injection signal (Vi1), outputs an output signal (Vo) and receives a second injection signal (Vi2) with a second frequency (f2). The frequency multiplier (220) uses injection locking to lock a frequency of the output signal (Vo) at a multiple of the first frequency (f1), and uses injection pulling to pull the frequency of the output signal (Vo) to the second frequency (f2). The transceiver (230) transmits the output signal (Vo) and receives a received signal (Vrx) with a third frequency (f3) for updating the second injection signal (Vi2). The demodulator (240) performs a demodulation operation according to the output signal (Vo) so as to generate a displacement signal (Vd).