Low Latency Acoustic Processor for Real-Time Noise Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing active noise cancellation systems suffer from latency issues due to high processing rates, which limit their effectiveness in reducing noise frequencies and result in discomfort from large, heavy headphones for extended wear.
Innovation Solution
A reconfigurable acoustic processor that operates at ultra-low latency by processing digitized sensor inputs at the same rate as they are generated, eliminating the need for decimation filters and allowing real-time noise cancellation through a combination of feed-forward and feedback ANC systems with programmable bi-quad filters and gain units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal processing is performed at common audio processing rates (44.1 KHz or 48 KHz), then audio quality is maintained, but latency increases significantly
Solution Approach 1:
The patent changes the processing rate parameter from conventional audio rates (44.1 KHz or 48 KHz) to ultra-high rates (2 MHz, 6 MHz, or higher). This parameter change enables the system to process audio signals with dramatically reduced latency (less than 2.5 µs) while maintaining audio quality through appropriate filter design optimized for the higher sampling rate.
2Device complexity
If decimation filters are used to reduce processing rate, then computational complexity is reduced, but latency increases
Solution Approach 1:
Instead of the conventional approach of using decimation filters to reduce processing rate after high-rate sampling, the patent inverts the approach by processing signals at ultra-high rates throughout the entire signal path and only applying decimation at the final output stage. This inversion eliminates intermediate decimation operations that would introduce latency, allowing the system to maintain low latency while managing computational complexity through optimized filter implementations.
3Loss of time
If processing rate is increased to reduce latency, then noise cancellation responsiveness improves, but computational complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct functional blocks operating at different rates: ultra-high rate processing (2 MHz or 6 MHz) is used only for the critical noise cancellation path where low latency is essential, while lower rate processing is used for less time-critical functions. This segmentation allows the system to achieve low latency for noise cancellation without unnecessarily increasing computational complexity across the entire system.
Solution Approach 2:
The patent implements dynamic processing where the system can adaptively adjust processing parameters based on input conditions. The reconfigurable architecture allows dynamic switching between different processing modes and rates, enabling the system to use ultra-high rate processing only when low latency is critical for noise cancellation, while operating at lower rates during less demanding conditions, thus balancing latency performance with computational complexity.
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
An audio system having low latency includes a digital audio processor as well as sensor inputs coupled to the processor. The sensor inputs may be microphone inputs. The audio processor operates at the same frequency as the sensor inputs, which is typically much higher than an audio signal provided to the audio processor. In some aspects the audio processor operates as a noise cancellation processor and does not include an audio input.