Temperature-Based DC Offset Compensation for Audio Pop Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic devices often produce annoying pop noise due to direct current (DC) offsets when turned on or off, as the output voltage of audio amplifiers suddenly changes, falling within the range of human audibility.
Innovation Solution
An audio device with a linear operation circuit, digital-to-analog circuit, amplification circuit, and temperature sensing circuit that generates a DC offset value based on a linear equation, slope parameter, and constant to compensate for the DC offset of an audio source signal, reducing noise emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the audio amplifier output voltage suddenly changes during power-up or power-down, then the audio device can be turned on or off quickly, but pop noise is generated due to DC offset
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing DC offset compensation values at different temperature points before actual operation. When the audio device powers up or down, the system quickly retrieves the pre-computed compensation value corresponding to the current temperature and applies it to cancel the DC offset, thereby eliminating pop noise while maintaining fast switching speed
Solution Approach 2:
The patent utilizes parameter changes by establishing a relationship between temperature and DC offset compensation values. The system measures temperature, selects or interpolates the corresponding compensation parameter from stored data, and dynamically adjusts the DC offset cancellation amount. This allows the compensation to adapt to temperature variations during power-up and power-down, effectively reducing pop noise across different operating conditions
2Measurement precision
If temperature compensation is implemented using a linear equation with slope and constant parameters, then DC offset compensation accuracy is improved, but device complexity increases due to additional circuits
Solution Approach 1:
The patent applies copying by pre-calculating and storing DC offset compensation values in a lookup table or memory during the design phase. Instead of implementing complex real-time calculations with multiple sensors and processors, the system copies the appropriate pre-computed compensation value from storage based on measured temperature, achieving high accuracy with minimal additional hardware complexity
Solution Approach 2:
The patent replaces complex mechanical or computational systems with a simplified electronic implementation. Rather than using multiple temperature sensors, analog-to-digital converters, and real-time mathematical computation units, the system substitutes these with a temperature sensing circuit that outputs directly to a lookup table or simple interpolator, achieving linear equation-based compensation with minimal circuit complexity
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
Effectively reduces pop noise by compensating for DC offsets in real-time based on temperature changes, ensuring that audio playing devices do not emit noise during power-up or power-down processes.
Implementation Method 1
The temperature sensing circuit generates a temperature parameter based on a temperature of the audio device and outputs the temperature parameter to the linear operation circuit
Data Source
AI summary
An audio device for reducing pop noise is adapted to compensate for a direct current (DC) offset of an audio source signal and output the audio source signal to an audio playing device. The audio device includes a linear operation circuit, an adder, a digital-to-analog circuit, and an amplification circuit. The digital-to-analog circuit is coupled between the adder and the amplification circuit. The linear operation circuit generates a DC offset value based on a linear equation, a temperature parameter, a slope parameter, and a constant. The adder is configured to process an input signal and the DC offset value to generate a calibration signal. The digital-to-analog circuit is configured to convert a calibration signal in a digital form to a calibration signal in an analog form. The amplification circuit is configured to process the calibration signal in the analog form to output the audio source signal.