Radio-Wave Voice Demodulation Using Phased Antenna Arrays
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Solution Overview
Problem
Traditional audio surveillance methods are easily detectable and obstructable, requiring direct line of sight or high power amplification, and are costly and impractical for large area coverage without multiple devices.
Innovation Solution
A phased antenna array system that receives signals from non-sound sources, processes them to locate and track movement, and demodulates sound waves using signal processors and sound demodulators, employing algorithms like Kalman filtering and sound recognition to identify and amplify voice signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional audio surveillance methods are used, then audio information can be captured, but the methods are easily detected and obstructed, reducing effectiveness
Solution Approach 1:
The patent replaces traditional mechanical audio surveillance methods (microphones, speakers) with an electromagnetic field-based system using phased antenna arrays to detect and demodulate sound waves from ambient electromagnetic signals, making the surveillance undetectable and unobstructable
Solution Approach 2:
The system uses ambient electromagnetic signals (radio waves, WiFi signals) as an intermediary carrier to transmit sound information, rather than directly capturing sound waves, allowing indirect and covert audio surveillance
2Reliability
If recording audio at a distance without listening devices is attempted, then secrecy is maintained, but direct line of sight or extremely high power sound amplification is required
Solution Approach 1:
The system replaces high-power acoustic amplification with low-power electromagnetic signal processing, using the energy of existing ambient electromagnetic signals to extract audio information at distances impossible for traditional acoustic methods
Solution Approach 2:
The phased antenna array system can detect both the presence and content of sound waves from various electromagnetic signal sources simultaneously, providing versatile surveillance capability without additional power requirements
3Area of stationary object
If multiple listening devices are deployed for large area surveillance, then audio information coverage is improved, but cost and complexity increase
Solution Approach 1:
The system segments the surveillance area into multiple detectable zones using a single phased antenna array, with each antenna element contributing to different spatial sectors, allowing comprehensive coverage without deploying multiple physical devices
Solution Approach 2:
The patent transitions from two-dimensional spatial deployment of multiple devices to three-dimensional electromagnetic field detection, using the phased array's ability to detect signals from all directions simultaneously to achieve area coverage with a single system
4Measurement precision
If traditional audio surveillance is used, then audio capture is possible, but precision tools are required and extraction from large areas is difficult
Solution Approach 1:
The system replaces precision acoustic measurement tools with electromagnetic signal processing techniques, using the higher frequency and better resolution characteristics of electromagnetic waves to achieve superior audio extraction precision from large areas
Solution Approach 2:
The patent combines multiple signal processing functions (location, movement detection, sound demodulation, noise filtering) into a unified system that processes electromagnetic signals, achieving high precision audio extraction without requiring separate precision tools for each function
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 secure, precise, and cost-effective surveillance of sound signals over large areas without direct line of sight, using passive and active modes to enhance signal clarity and accuracy.
Implementation Method 1
a phased antenna array configured to receive signals from at least one signal source
Implementation Method 2
triangulate a location of the at least one signal source using an angle of arrival (AoA) calculation based on a difference in phase and time of the received signals
Implementation Method 3
detecting a movement of the at least one signal source relative to the phased antenna array wherein the detected movement is at least partially in response to sound waves impinging on the at least one signal source
Implementation Method 4
a sound demodulator configured to demodulate the sound waves from the detected movement
Data Source
AI summary
A system includes a phased antenna array configured to receive signals from at least one signal source not initially designed to provide a signal related to sound. The system also includes a signal processor configured to locate the at least one signal source using the received signals and detect a movement of the at least one signal source relative to the phased antenna array, wherein the detected movement is at least partially in response to sound waves impinging on the at least one signal source. The system further includes a sound demodulator configured to demodulate the sound waves from the detected movement.