Microphone IC Echo Cancellation With Dynamic Gain Matching
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Solution Overview
Problem
Conventional audio processing devices with full-duplex capabilities face issues such as separate digital signal processors and analog-to-digital converters occupying a large layout area, leading to increased size and poor signal quality due to unadjustable gain and echo saturation, which degrades the signal-to-noise ratio.
Innovation Solution
An integrated circuit within a microphone that includes a pre-amplifier, analog-to-digital converter, digital signal processor, and post-amplifier, which receives a reference signal for echo cancellation, adjusts gains to maintain signal quality and prevent saturation, and transmits signals via a single data line for efficient echo removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate digital signal processor and analog-to-digital converter are used, then echo cancellation and signal conversion functions are independent and reliable, but the layout area increases and device size becomes larger
Solution Approach 1:
The patent integrates the digital signal processor and analog-to-digital converter into a single integrated circuit chip. The ADC module and DSP module are combined in one chip, allowing echo cancellation processing and signal conversion to occur within the same device footprint. This merging reduces the layout area while maintaining the functional independence and reliability of both processing stages through modular internal architecture.
2Reliability
If gain adjustment capability is added, then signal quality improves under varying amplitude conditions, but device complexity increases
Solution Approach 1:
The patent implements dynamic gain adjustment through a variable gain amplifier stage that can adaptively modify signal amplitude based on input conditions. The system dynamically switches between different gain states (first gain for normal conditions, second gain for low-amplitude conditions) to optimize signal quality. This dynamic capability allows the device to maintain high signal quality across varying acoustic conditions without requiring multiple fixed-gain amplifier stages, thus limiting the increase in device complexity.
3Area of stationary object
If echo cancellation processing is integrated into the microphone, then device size reduces, but the microphone structure becomes more complex
Solution Approach 1:
The patent combines the microphone capsule and echo cancellation processing circuitry into a single integrated unit. The microphone element is directly connected to the integrated circuit that performs echo cancellation, eliminating the need for separate external processing devices. This integration reduces overall device size while the internal modular structure of the integrated circuit manages the complexity of combining acoustic conversion and digital signal processing functions.
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
The integrated solution reduces the size of the audio processing device, enhances signal quality by maintaining proper gain and preventing echo saturation, and improves the signal-to-noise ratio, resulting in a more compact and effective audio processing system.
Implementation Method 1
a microphone cartridge (212) and an integrated circuit (214). The microphone cartridge converts the sound to a first signal
Implementation Method 2
The pre-amplifier amplifies the first signal according to a first gain to obtain a third signal
Implementation Method 3
The analog-to-digital converter converts the third signal from analog to digital to obtain a fourth signal
Implementation Method 4
The digital signal processor cancels an echo component from the fourth signal according to the reference signal to obtain a fifth signal
Implementation Method 5
The post-amplifier amplifies the fifth signal according to the second gain to obtain a second signal as an output of the integrated circuit
Data Source
AI summary
The invention provides an integrated circuit of a microphone. In one embodiment, the integrated circuit receives a first signal converted from a sound and receives a reference signal with a digital format for echo cancellation. In one embodiment, the integrated circuit comprises a pre-amplifier, an analog-to-digital converter, a digital signal processor, and a post amplifier. The pre-amplifier amplifies the first signal according to a first gain to obtain a third signal. The analog-to-digital converter converts the third signal from analog to digital to obtain a fourth signal. The digital signal processor cancels an echo component from the fourth signal according to the reference signal to obtain a fifth signal, and determines the first gain and a second gain, wherein a product of the first gain and the second gain is kept constant, and the first gain is determined so that an amplitude of the third signal is kept equal to an amplitude of the reference signal. The post-amplifier amplifies the fifth signal according to the second gain to obtain a second signal as an output of the integrated circuit.