Microwave Module Self-Test via Frequency-Varying Power Pulses
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Solution Overview
Problem
Existing self-test methods for microwave intrusion detectors are ineffective due to variability in supervision signal amplitude, high costs associated with noise circuits, and incorrect fault threshold evaluations, leading to false alarms or failure to detect circuit integrity issues.
Innovation Solution
A self-test circuit and method utilizing a master control unit, signal processing unit, microwave module, and power module that generates controlled power pulses at specific frequencies to assess the microwave module's integrity, eliminating the need for noise circuits and using software algorithms to determine normal operation based on sampled signal thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional self-test methods are used to monitor microwave module integrity, then detection capability is provided, but false alarms occur due to variability in supervision signal amplitude and incorrect fault threshold evaluations
Solution Approach 1:
The patent changes the parameter of fault threshold evaluation from fixed amplitude-based thresholds to dynamic thresholds based on signal frequency characteristics and power spectral density analysis. This allows the system to adapt to signal variability while maintaining accurate fault detection, resolving the contradiction between detection capability and measurement precision.
Solution Approach 2:
The patent replaces traditional amplitude-based mechanical threshold comparison with a software-based spectral analysis system using Fast Fourier Transform (FFT) and power spectral density calculations. This substitution enables more precise fault detection by analyzing frequency domain characteristics rather than relying on variable amplitude measurements.
2Reliability
If noise circuits are included to ensure proper functioning of microwave detectors, then detection reliability is improved, but system cost increases
Solution Approach 1:
The patent implements self-service by using the microwave module's own operational signals for self-testing rather than requiring separate noise circuits. The system uses its transmitted and received signals to perform autocorrelation and spectral analysis, eliminating the need for additional external testing equipment and reducing system cost while maintaining detection reliability.
Solution Approach 2:
The patent makes the microwave module multi-functional by enabling it to perform both its primary detection function and self-testing function using the same hardware resources. The signal processing unit handles both intrusion detection and integrity monitoring, eliminating the need for dedicated noise circuits and reducing overall system complexity.
3Reliability
If periodic self-testing is implemented to ensure normal functioning, then failure detection capability is improved, but system complexity increases
Solution Approach 1:
The patent merges the self-testing function with the existing signal processing unit and control unit, rather than adding separate testing hardware. The same processors and memory used for intrusion detection are utilized for integrity monitoring, combining multiple functions into unified system components and avoiding increased physical complexity.
Solution Approach 2:
The patent implements continuous self-testing by periodically injecting test signals and analyzing responses in real-time during normal operation. This continuous monitoring approach ensures failure detection capability without requiring separate testing phases or additional hardware, maintaining system simplicity while providing ongoing reliability verification.
Data Source
AI summary
A method and apparatus are provided for automatically testing microwave instruction detection modules of a security system. The method includes the steps of detecting intruders within a protected space by monitoring a Doppler output of a signal extraction circuit coupled to a microwave transceiver module, varying a frequency of direct current power pulses applied to the microwave transceiver module, detecting a difference in magnitude of the Doppler output of the signal extraction circuit over the varied frequency and comparing the detected difference with a fault threshold level.