Acoustic Processor Low Latency Noise Cancellation
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Solution Overview
Problem
Existing Active Noise Cancellation systems suffer from latency issues due to digitizing and processing sensor signals at rates common in audio processing, which limits their effectiveness in canceling noise, especially at higher frequencies.
Innovation Solution
A reconfigurable acoustic processor that operates at higher frequencies, eliminating the need for decimation filters and allowing real-time processing of sensor signals with minimal latency, using a digital signal processor and programmable bi-quad filters to generate anti-noise signals efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sensor signals are digitized and processed at common audio processing rates (44.1 KHz or 48 KHz), then the system is easier to implement, but latency increases significantly
Solution Approach 1:
The patent changes the processing rate parameter from common audio rates (44.1 KHz or 48 KHz) to a higher rate (at least 1 MHz). This parameter change reduces the processing latency from hundreds of microseconds to less than 2.5 microseconds, while still maintaining ease of implementation through systematic processing approaches.
2Reliability
If the acoustic processor operates at higher frequencies to reduce latency, then noise cancellation effectiveness improves, but the device complexity increases
Solution Approach 1:
The patent segments the processing system into distinct functional blocks: a first digital signal processor for initial signal processing, a decimation filter for rate conversion, and a second digital signal processor for anti-noise generation. This segmentation manages complexity by organizing high-frequency processing into modular, manageable components.
Solution Approach 2:
The decimation filter acts as an intermediary between the high-frequency processing stage and the anti-noise generation stage. It bridges the gap between the fast processing required for low latency and the controlled processing needed for accurate noise cancellation, managing the transition between different processing rates.
3Adaptability or versatility
If decimation filters are used to convert from high processing rates to audio rates, then compatibility with standard audio systems is improved, but processing latency increases
Solution Approach 1:
The system performs preliminary anti-noise generation at high processing rates before converting to audio rates. By generating the anti-noise signal in advance at the optimal high rate, the system ensures low latency while the decimation filter only needs to convert the already-generated signal, not process it from scratch.
Data Source
AI summary
An audio processing system can include an Analog to Digital Converter structured to receive an analog input signal and convert the analog input signal to a digital input signal, a first processor coupled with the Analog to Digital Converter, the first processor including at least one programmable bi-quadratic filter chain structured to receive the digital input signal from the Analog to Digital Converter and perform audio processing on the received digital input signal at a first clock rate, and a second processor coupled with the first processor and the Analog to Digital Converter and structured to receive the digital input signal from the Analog to Digital Converter and perform audio processing on the received digital input signal at a second clock rate that is different from the first clock rate.