Electroacoustic Transducer Passive Balancing for External Sound Detection
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Solution Overview
Problem
Current electroacoustic transducer systems require additional active circuitry to detect external sound, increasing complexity and cost, and typically operate in limited half-duplex or push-to-talk modes, whereas a system capable of both producing and receiving sound without additional components is desirable.
Innovation Solution
The system uses electroacoustic transducers in a monophonic mode with one transducer providing a monophonic output of opposite phase to another, canceling out the output signals at a common electrical point to isolate and amplify the residual 'microphone' signal representing environmental sound, eliminating the need for a separate microphone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional active circuitry is used to detect external sound with transducers, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the electroacoustic transducers perform dual functions: serving as both sound output devices and sound detection devices. By using the same transducer components for both actuation and sensing, the system eliminates the need for separate microphones and additional active circuitry, thereby reducing device complexity while maintaining external sound detection capability
Solution Approach 2:
The transducers detect external sound using their own passive electromagnetic induction capability without requiring external active components. The transducers self-generate electrical signals in response to acoustic pressure changes, enabling autonomous detection functionality built into the existing components
2Measurement precision
If transducers operate in half-duplex or push-to-talk mode, then external sound detection is enabled, but communication versatility deteriorates
Solution Approach 1:
The system enables transducers to simultaneously function as both sound output actuators and sound detection sensors during full-duplex operation. This multi-functionality allows continuous two-way communication where audio playback and speech capture occur concurrently without mode switching, enhancing communication versatility
Solution Approach 2:
The patent inverts the conventional approach by using the transducer's passive sensing capability (electromagnetic induction) rather than requiring active microphone circuitry. This inversion enables the output device to also serve as the input device, allowing simultaneous transmit and receive operations in full-duplex mode
3Measurement precision
If a separate microphone is used for sound detection, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the electroacoustic transducers perform dual functions: serving as both sound output devices and sound detection devices. By using the same transducer components for both actuation and sensing, the system eliminates the need for separate microphones and additional active circuitry, thereby reducing device complexity while maintaining external sound detection capability
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 approach allows for the detection of external sounds without additional active components, enhancing communication by reducing noise interference and enabling the capture of speech, vital signs, and environmental events, while maintaining the transducers' primary function of producing sound.
Implementation Method 1
Each voice coil 102 is driven by an amplifier 106, which causes the voice coil 102 to drive the diaphragm 104 thereby converting an audio signal into sound
Implementation Method 2
an electroacoustic transducer is in principle itself capable of acting as both an actuator that produces sound and a detector that can receive sound
Implementation Method 3
providing the inverted monophonic audio signal to a second voice coil... receiving at a common electrical point coupled to the first and second voice coils the monophonic audio signal and the inverted monophonic audio signal, causing the monophonic audio signal and the inverted monophonic audio signal to cancel out
Data Source
AI summary
A system and method for passively balancing electroacoustic transducers so that sounds other than the transducer's output can be detected. A transducer producing audio output based upon an input audio signal can operate in reverse to produce a signal in response to the impact of external sound upon the transducer from another source. This “reverse” or “microphone” signal represents the sound from the other source. Transducers are operated in monophonic mode, each in opposite polarity to the other thus canceling out and leaving only the microphone signal created by the transducers, i.e., a signal representing the external sound. The microphone signal can be amplified, and can be filtered and processed to identify and/or obtain various types of information about the sound received by the transducers.