Wireless Detection Apparatus Using Injection-Locking for Vital Signs
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Solution Overview
Problem
Conventional non-contact physiological signal detectors using Doppler radar suffer from destructive interference, complex circuit architecture, high power consumption, and inconsistent results due to varying detection distances, making them uncomfortable for long-term use and costly.
Innovation Solution
A wireless detection apparatus employing a voltage control oscillator and processing unit that utilizes an injection-locking technique to amplify phase modulation from the thoracic wall movements, generating an oscillating signal for evaluating vital signs without the need for physical contact, using either wireless or light signals to synchronize with the object's movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional Doppler radar construction is used, then non-contact physiological signal detection is achieved, but destructive interference occurs causing detection zero-points at particular positions
Solution Approach 1:
The patent changes the fundamental operating parameter from conventional Doppler radar to injection-locking technique. The voltage control oscillator generates oscillating signals that are locked to the frequency of the reflected wireless signal, eliminating the destructive interference problem inherent in conventional Doppler radar while maintaining non-contact detection capability.
Solution Approach 2:
The patent replaces the mechanical mixing process of conventional Doppler radar with an electronic injection-locking mechanism. Instead of mechanically mixing reflected and reference signals, the system uses a voltage control oscillator that electronically locks to the reflected signal frequency, substituting mechanical interference-based detection with electronic frequency locking.
2Ease of operation
If conventional Doppler radar construction is used, then non-contact physiological signal detection is achieved, but circuit architecture becomes complex
Solution Approach 1:
The patent extracts and eliminates the complex mixing circuitry and power splitter components from conventional Doppler radar. By using injection-locking, the system removes the need for signal mixing, reference signal generation, and complex phase comparison circuits, retaining only the essential voltage control oscillator and simple signal processing components.
Solution Approach 2:
The voltage control oscillator serves multiple functions simultaneously: it generates the oscillating signal, locks to the reflected signal frequency, and provides the detection mechanism. This multi-functionality replaces the multiple separate components needed in conventional Doppler radar, simplifying the overall circuit architecture while maintaining non-contact detection capability.
3Ease of operation
If conventional Doppler radar construction is used, then non-contact physiological signal detection is achieved, but power consumption increases
Solution Approach 1:
The injection-locking technique uses periodic oscillations at the frequency of the reflected signal rather than continuous high-power transmission and mixing. The voltage control oscillator operates at the locked frequency, creating periodic oscillating signals that consume less power than continuous Doppler radar transmission while maintaining effective detection.
4Ease of operation
If conventional Doppler radar construction is used, then non-contact physiological signal detection is achieved, but detecting results become inconsistent due to distance variation
Solution Approach 1:
The injection-locking system incorporates implicit feedback through the locking mechanism itself. The voltage control oscillator continuously adjusts its output frequency to match the reflected signal frequency, automatically compensating for distance variations and maintaining consistent detection results regardless of the detector's position relative to the object being measured.
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 non-contact, efficient, and accurate monitoring of physiological parameters like heartbeat, pulse, and movements with reduced complexity and power consumption, providing consistent results and improved user comfort.
Implementation Method 1
A wireless detection apparatus employing a voltage control oscillator and processing unit that utilizes an injection-locking technique to amplify phase modulation from the thoracic wall movements, generating an oscillating signal for evaluating vital signs
Implementation Method 2
The first antenna is adapted to receive a first wireless signal and generate an electrical signal according to the first wireless signal. The first wireless signal is generated by reflecting a second wireless signal from an object under test.
Implementation Method 3
The oscillating signal varies with variation of the electrical signal. The processing unit is coupled to the voltage control oscillator and adapted to evaluate a parameter of the object under test according to the variation of the oscillating signal.
Data Source
AI summary
A wireless detection apparatus includes an antenna, a voltage control oscillator, and a processing unit. The antenna receives a first wireless signal and generates an electrical signal according to the first wireless signal. The first wireless signal is generated by reflecting a second wireless signal from an object under test. The voltage control oscillator is coupled to the antenna to generate an oscillating signal under an interference of the electrical signal. The oscillating signal varies with variation of the electrical signal. The processing unit is coupled to the voltage control oscillator to evaluate a parameter of the object under test according to the variation of the oscillating signal.