Loudspeaker Voice Coil Temperature Estimation via Audio Signal Cancellation
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Solution Overview
Problem
Existing loudspeaker technologies lack accurate methods to estimate voice coil temperature due to interference from audio signals, leading to inaccurate temperature assessments.
Innovation Solution
A device comprising a signal generator, signal adjuster, adder, and temperature estimator that uses a measurement signal with an inaudible frequency to estimate voice coil resistance, combining it with an inverted audio signal to generate a blended signal for precise resistance and temperature estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measurement signal is injected into the loudspeaker to estimate voice coil temperature, then temperature estimation becomes possible, but audio signal interference causes measurement inaccuracy
Solution Approach 1:
The patent extracts the measurement signal from the mixed audio signal by using an inverted audio signal to cancel out the original audio signal. The adder combines the sensory output (containing measurement signal plus audio signal plus noise) with the inverted audio signal, effectively removing the audio signal interference and isolating the measurement signal for accurate temperature estimation.
Solution Approach 2:
The patent applies preliminary anti-action by generating an inverted audio signal before the addition process. This inverted signal is specifically designed to counteract and cancel the audio signal interference in the sensory output, preventing the harmful effect from corrupting the measurement signal extraction process.
2Object-affected harmful factors
If the measurement signal uses audible frequency, then it may interfere with audio quality, but if it uses inaudible frequency, then it becomes more difficult to separate from audio signals
Solution Approach 1:
The patent uses feedback by feeding back the inverted audio signal to the adder to cancel out the original audio signal component in the sensory output. This feedback mechanism continuously compensates for the audio signal interference, enabling effective separation of the measurement signal regardless of its frequency characteristics.
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
Enhances the accuracy of voice coil temperature estimation by isolating the measurement signal from audio interference, allowing for more precise resistance and temperature calculations.
Implementation Method 1
electric current is applied to the voice coil of the loudspeaker, leading to the generation of thermal energy in the voice coil
Implementation Method 2
obtains a resistance estimate for the loudspeaker voice coil. Based on this resistance estimate, it generates a temperature signal indicating an estimated temperature value
Data Source
AI summary
A device for estimating the temperature of a loudspeaker's voice coil includes a signal generator, a signal adjuster, an adder, and a temperature estimator. The signal generator generates and outputs an amplified signal to a loudspeaker according to a measurement signal and an audio signal, and senses a voltage and a current of the amplified signal to generate and output a sensory output. The signal adjuster generates and outputs an inverted signal according to the audio signal. The adder adds the sensory output and the inverted signal to generate a blended signal. The temperature estimator obtains an estimated resistance value of the loudspeaker's voice coil according to the blended signal, and generates a temperature signal according to the estimated resistance value, wherein the temperature signal indicates an estimated temperature value of the loudspeaker's voice coil. Additionally, a method for estimating the temperature of the loudspeaker voice coil is provided.