Speakerphone with Remote Cable Microphone for Echo Cancellation

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Solution Overview

Problem

Conventional speakerphones face challenges in achieving effective echo cancellation, particularly at close microphone-loudspeaker distances, leading to suboptimal signal-to-echo ratios and echo perception, especially in small form factor designs where the microphone and loudspeaker are closely positioned, resulting in reduced echo cancellation effectiveness.

Innovation Solution

The speakerphone design features a loudspeaker housed within a unit and a remotely located microphone on a cable or connector, mechanically isolating the microphone and loudspeaker to increase the distance between them without expanding the device's form factor, thereby enhancing the signal-to-echo ratio and reducing structural sound transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the microphone and loudspeaker are positioned close together in a small form factor device, then the device size is reduced, but the signal-to-echo ratio deteriorates and echo cancellation effectiveness is reduced

Engineering Contradiction:

Improvedevice sizeVSAvoidecho cancellation effectiveness

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent divides the speakerphone system into two separate modules: a compact housing containing the loudspeaker and a remote microphone positioned on an extended cable or boom. This segmentation allows the microphone to be physically separated from the loudspeaker, increasing the distance between them and improving the signal-to-echo ratio while maintaining a small form factor housing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extends the microphone position from the traditional in-housing two-dimensional plane to a three-dimensional space by using an extendable cable or boom mechanism. This allows the microphone to be positioned in a different spatial dimension, farther from the loudspeaker, thereby improving acoustic performance without increasing the housing volume.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If the microphone is positioned close to the loudspeaker, then the device complexity is reduced, but the structural sound transmission increases and audio quality deteriorates

Engineering Contradiction:

Improvemicrophone positioning structureVSAvoidstructural sound transmission

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the microphone from the housing structure and positions it on a separate cable or boom. This extraction removes the microphone from the structural path of sound vibrations generated by the loudspeaker, thereby reducing structural sound transmission and improving audio quality while keeping the housing design simple.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the microphone-loudspeaker distance is increased, then the signal-to-echo ratio is improved, but the device form factor must be enlarged

Engineering Contradiction:

Improvesignal-to-echo ratioVSAvoiddevice form factor

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs a dynamic, extendable cable or boom mechanism that allows the microphone to be positioned at variable distances from the housing. When extended, the microphone achieves optimal separation from the loudspeaker for improved signal-to-echo ratio; when retracted, the device maintains a compact form factor. This dynamic positioning resolves the contradiction between distance and size.

Inventive Principle:

Principle #15Dynamics

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

This configuration improves the signal-to-echo ratio beyond conventional limits, achieving full duplex support with minimal echo, even in small form factor devices, by increasing the microphone-loudspeaker separation and reducing structural sound conduction, thus enhancing the overall audio quality.

Implementation Method 1

a loudspeaker in a housing and a remotely located microphone on a cable or on a connector at a distal end of the cable

Methodology Applied

Scientific EffectElectroacoustic transduction:

Implementation Method 2

The transmitting transducer is affixed to the electrical cable, remote from the housing

Methodology Applied

Scientific EffectAcoustic transduction:

Implementation Method 3

mechanically isolating the microphone and loudspeaker to increase the distance between them without expanding the device's form factor, thereby enhancing the signal-to-echo ratio and reducing structural sound transmission

Methodology Applied

Scientific EffectMechanical isolation: Damping

Data Source

PatentUS10182160B2Speakerphone system or speakerphone accessory with on-cable microphone

Publication Date: 2019.01.15 AVNERA CORP

AI summary

A portable speakerphone having a housing, a receiving transducer, an electrical cable, a transmitting transducer, and a processor. The receiving transducer is affixed to the housing and is configured to receive a first electrical signal from a mobile device. The electrical cable is coupled to and extends from the housing. The transmitting transducer is affixed to the electrical cable, remote from the housing. Also, the transmitting transducer is configured to transmit a second electrical signal, and the second electrical signal is based in part on the first electrical signal. The processor is configured to suppress acoustic echo by modifying the second electrical signal. The processor is also configured to output the modified second electrical signal to the mobile device. A related method is also disclosed.