Module Tester for Audio Null Steering Calibration
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Solution Overview
Problem
Existing module testers are insufficient for properly testing and calibrating response select null steering circuits, which are complex and require precise evaluation to ensure effective noise cancellation in audio signal processing systems.
Innovation Solution
A new module tester is developed that includes a beamformer, summing circuit, separate filtering circuits, and a selection circuit to generate and select output signals with the least signal energy, optimizing the suppression of unwanted interferers while preserving desired speaker signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency filtering is used to cancel unwanted interferers, then noise cancellation is achieved, but the frequencies to be filtered out are typically the same as the desired source, making filtering unsuccessful
Solution Approach 1:
The audio signal processing system segments the spatial domain by using an array of multiple microphones positioned at different locations. Each microphone captures sound signals from different spatial directions, allowing the system to separate desired speaker signals from unwanted interferers based on their spatial positions rather than frequency characteristics. This spatial segmentation enables effective noise cancellation without interfering with the frequency content of the desired signal.
Solution Approach 2:
The system transitions from frequency-domain filtering to spatial-domain processing by utilizing the geometric arrangement of multiple microphones in three-dimensional space. The beamformer algorithms operate on the spatial relationships between microphone signals, creating directional sensitivity patterns that can selectively enhance sounds from specific directions while suppressing sounds from other directions. This dimensional shift from frequency to space resolves the contradiction by providing a new degree of freedom for signal separation.
2Object-affected harmful factors
If directional microphones with arrays of sensors are used to increase directionality, then spatial separation of speaker and interferers is achieved, but the system complexity increases
Solution Approach 1:
The microphone array system performs multiple functions simultaneously: it captures acoustic signals from various directions, enables spatial filtering through beamforming, provides directional sensitivity patterns, and facilitates adaptive null-steering for interference cancellation. By making the system multi-functional, the patent justifies the increased complexity through the gain in capability, as a single array-based system replaces what would otherwise require multiple separate processing stages or systems.
Solution Approach 2:
The system incorporates feedback mechanisms through adaptive filters that continuously adjust their operation based on the acoustic environment. The adaptive null-steering capability uses feedback from the microphone array to dynamically modify the directional sensitivity pattern, allowing the system to track and suppress moving interferers while maintaining focus on the desired speaker. This feedback loop enables the complex system to adapt to changing conditions automatically.
3Object-affected harmful factors
If adaptive filters are employed to continually modify the system response for interference cancellation, then the null can be steered in the direction of the interferer, but the computational complexity and processing requirements increase
Solution Approach 1:
The system dynamically adjusts its directional sensitivity pattern through adaptive filtering, allowing the null to be steered in real-time toward the location of unwanted interferers. The beamformer algorithms continuously modify the weightings of individual microphone signals based on the current acoustic scene, enabling the system to adapt to moving speakers and interferers. This dynamic capability provides effective interference suppression while maintaining computational efficiency through optimized algorithm design.
Data Source
AI summary
A test system is configured to perform testing and calibration on a sound processing system by generating a test sound signal and measuring the outputs of the sound processing system in response to the test sound signal. The test system includes precision measurement instrumentation for measuring amplitudes and phases of signals generated by the sound processing system. The test system transmits configuration signals to the sound processing system to programmatically adjust one or more programmable gains and delays of the sound processing system.