Microphone Array Ethernet Audio Processing
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Solution Overview
Problem
Conventional microphone arrays require pre-configuration of directional lobes and are limited in simulating multiple physical microphones, while remote audio processing over Ethernet networks is impractical due to bandwidth and processing limitations, leading to suboptimal audio quality and increased delay in conferencing environments.
Innovation Solution
A ceiling-mounted microphone array with dedicated sigma-delta modulators transmitting raw, unconverted digital audio over a fast Ethernet network, allowing for additional processing like beamforming and echo cancellation by a remotely connected audio processor, which performs data-interleaving, checksum computation, and packet formation to optimize audio data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If beam-forming signal processing is performed within the microphone array circuitry, then audio processing capability is provided, but the array is limited to simulating only a few physical microphones and requires lobe pre-configuration
Solution Approach 1:
The patent extracts the complex beam-forming signal processing function from the microphone array circuitry and relocates it to a remote audio processing unit. This allows the array to transmit raw audio data without pre-configuration limitations, enabling the remote unit to dynamically simulate any number of virtual microphones with flexible directional patterns.
Solution Approach 2:
The system segments the audio processing workflow into two parts: the microphone array captures and transmits raw audio data, while the remote audio processing unit performs beam-forming and virtual microphone simulation. This segmentation removes the constraint of lobe pre-configuration at the array level.
2Reliability
If additional processing functions (echo cancellation, noise reduction) are performed at the microphone array, then audio quality is improved, but network bandwidth and processing power requirements increase
Solution Approach 1:
The patent performs preliminary processing at the remote audio processing unit by receiving raw audio data from the array and then applying beam-forming, echo cancellation, and noise reduction algorithms. This approach maintains high audio quality while using network bandwidth only for transmitting the raw captured data, not for processed audio streams.
3Adaptability or versatility
If remote audio processing is implemented over Ethernet network, then processing flexibility is increased, but time delay and processing limitations occur
Solution Approach 1:
The patent replaces traditional analog audio processing with digital signal processing over Ethernet network. By using digital communication protocols and network infrastructure, the system achieves processing flexibility previously unavailable in analog systems while maintaining acceptable real-time performance through efficient data transmission.
Data Source
AI summary
A microphone array configurable to connect via an Ethernet connection with an audio processor includes a plurality of MEMS microphones (7101-7121), a plurality of sigma-delta modulators (7201-7221), a processor and storage (90), and an Ethernet physical interface (80) operating at a network data transmission rate. Each sigma-delta modulator converts the analog output of a corresponding microphone into a bit stream at an audio sampling rate. The processor and storage performs a data-interleaving operation (92) to combine the bit streams from the sigma-delta modulators into a microphone audio frame serial bit stream (34), and loads the microphone audio frame serial bit stream into a FIFO memory (94) at a FIFO serial data load rate. The processor and storage computes an Ethernet FCS checksum on the microphone audio frame serial bit stream, concatenates, an FCS delay gap, the Ethernet FCS checksum, a timing gap, a frame prefix, a UDP/IP prefix, a payload, and the microphone audio frame serial bit stream to form an Ethernet frame packet serial bit stream, unloads this Ethernet packet serial bit stream from the FIFO memory at the network data transmission rate and transmits the Ethernet frame packet serial bit stream from the Ethernet physical interface.